CA2226446C - Flexible mobility management in a two-way messaging system and method therefor - Google Patents
Flexible mobility management in a two-way messaging system and method therefor Download PDFInfo
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- CA2226446C CA2226446C CA002226446A CA2226446A CA2226446C CA 2226446 C CA2226446 C CA 2226446C CA 002226446 A CA002226446 A CA 002226446A CA 2226446 A CA2226446 A CA 2226446A CA 2226446 C CA2226446 C CA 2226446C
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
- H04W88/02—Terminal devices
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W84/00—Network topologies
- H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
- H04W84/022—One-way selective calling networks, e.g. wide area paging
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W68/00—User notification, e.g. alerting and paging, for incoming communication, change of service or the like
- H04W68/04—User notification, e.g. alerting and paging, for incoming communication, change of service or the like multi-step notification using statistical or historical mobility data
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Abstract
A two-way messaging system (100) having a plurality of message subscriber units (500) and a base station (220) in each of a plurality of cells (210). The base station has a transmitter (224) for transmitting messages in an associated cell (210) and a receiver (228) associated therewith for receiving response signals from message subscriber units in a cell. A
system controller (300) is coupled to each base station (220) and has a memory (320) for storing the customer paging area data for each message subscriber unit. The system controller (300) receives message requests and automatically updates the customer paging area data for each message subscriber unit (500) by tracking the mobility pattern of each message subscriber unit (500) in the messaging system coverage area (200).
system controller (300) is coupled to each base station (220) and has a memory (320) for storing the customer paging area data for each message subscriber unit. The system controller (300) receives message requests and automatically updates the customer paging area data for each message subscriber unit (500) by tracking the mobility pattern of each message subscriber unit (500) in the messaging system coverage area (200).
Description
WO 97/03529 PCT/U~ C~6 FLEXIBLE MOBILITY MANAGEMENT IN A TWO-WAY MESSAGING
SYSTEM AND METHOD T~:IF.~FFOR
Field of the Invention The present invention is directed to a two-way mPss~ging system, and more particularly to a method and apparatus for efficiently managing system capacity with minimal system complexity and optimal battery power utilization in a subscriber unit.
Background of the Invention Paging systems have evolved into more robust communication systems capable of transmitting alphanllmPric, voice and image data to 15 portable receivers. Two-way paging systems are on the horizon. In a two-way paging system, the portable device transmits a limited content response signal which i~ lPs a reply mpssage or an acknowlPfi~nPnt message in response to receiving a mP~sSage. Thus, the term "mP~ssaging is a broader term which encompasses the transmi~sion of data messages, 20 voice messages, fa~ similP mP~s~ges, etc., as well as col,L~ln~lating the transmissiQn back from the portable or remote unit of a response signal which is a reply mPss~ge or an acknowlellgmPnt message.
A mes~ging system comprising a plurality of message subscriber units (capable of receiving mPss~ges and transmitted response signals) will 25 accommodate a variety of mPssage types, some which require more "air-time", such as data mPss~ges and fa~ simile mf~ss~, than others. The challenge is to optimize the tran~mi~sion of mp~ss~ges to message subscriber units so as to maintain a high system capacity. Part of this challenge involves transmitting mPss~ges only in those portions of a 30 mPss~ging system coverage area where the meSsage subscriber unit is likely to be located.
~ Brief Description of the Dldwil~S
FIG. 1 is an P1Pctri~ al block diagram illustrating the two-way mP~ss~ging system according to a ~re~lled embodiment of the present invention.
CA 02226446 l998-Ol-Oi FIG. 2 is an ~ ctric~l block diagram illustrating a base station and a mf~S~ge subscriber unit, and commtlnication there between according to the present invention.
FIGS. 3 and 4 are flow charts which generally illustrate the method of managing communication of a two-way me~ ing system according to the preferred embodiment of the present invention.
FIG. 5 is a diagram showing a m~oscAging system coverage area and 10 the dyn~mi~lly changing customer paging areas associated with mess~ge subscriber units in the two-way m~s~gin~ system according to the preferred embodiment of the present invf~ntion FIG. 6 is an electri~l block diagram of a mP~s~ge subscriber un*
15 according to the ~ref~lled embodiment of the present invention.
FIG. 7 is an ~l~ctricAl block diagram of a decoder/controller of a m~s~ge subscriber unit according to the ~rer~ d embodiment of the present invention.
FIG. 8 is a flow chart which illustrates a procedure for receiving a mess~ge request and tran.Cii~ g a mPs~ge to a message subscriber unit according to the ~refelled embo~lim~nt of the present il-v~l~Lion.
FIG. 9 is a flow chart which illustrates a procedure by which a mf~s~ge subscriber unit receives and acknowledges a mpss~e according to the ~re~.led embodiment of the present invention.
FIG. 10 is a flow chart which illustrates a procedure for determining 30 a location of a m~s~ge subscriber unit according to the ~reLelled embodiment of the present invention.
FIG. 11 is a flow chart which illustrates a procedure for updating customer paging area data according to the ~reLeLled embodiment of the 35 present invention.
WO 97/03529 PCT/U.,~ 6C~6 FIG. 12 is a flow chart illustrating a procedure in messAge subscriber unit for registering a location which leaves its customer paging area ~ according to the preferred embodiment of the present invention.
FIG. 13 is a flow chart illustrating a procedure for processing a registration signal from a m~c~Age subscriber unit which leaves its customer paging area according to the ~reLlred embodiment of the present invention.
DetAil~l Description of the Dldwil~gs FIG. 1 illustrates a two-way mP~sAging system according to the present invention. The messAging system 100 is designed to provide commun~ation throughout a m~sAging ~y~leln coverage area (MSCA) 200. The MSCA 200 cull,ylises a plurality of cells 210, and each cell comprises a base station 220 and at least one antenna 230. FIG. 1 shows that there are 12 cells, numbered C1-C12 each with a base station BS1-BS12;
however it should be understood that 12 cells is only an example and that the MSCA 200 can cc,ll-ylise any numbered of cells as is ~c~sAry to provide coverage within a me~cAging system. Moreover, the cells do not cf~ rily have the geometric conAguration shown in FIG. 1. Multiple cells are grouped into a zone such that zone 1 comprises cells C1, C5 and C9, zone 2 comylises cells C2, C3, C6, C7, C10 and C11, and zone 3 ccll,ylises cells C4, C8 and C12.
A system controller 300 is coupled to each base station 220 and oversees control of communication throughout the MSCA 200. The system controller 300 colllylises a m~sAge memory 310, a customer paging area (CPA) memory 320 and a processor 330. Message requests are received by the system controller 300 through the public telephone system network (PTSN) 400 and are stored in the mes~Age memory 310 for processing. The CPA memory is for storing customer paging area data as well as for storing location registration information concerning each subscriber unit in the system, which is explained in greater detail hereinafter. Messages are also passed to the system controller 300 through electronic-mail networks including the Internet.
Depending on the size of a MSCA and the number of cells therein, there are more than one ~yble,ll controller for the MSCA, each being ~e~icAte~ to a particular subset of cells.
CA 02226446 l998-0l-07 Message requests can originate from one of many types of sources, of which PIG. 1 illustrates a few as examples. NllmPric and voice mps~ges can originate from a conventional handset phone 410 (wired or wireless).
Alph~nllm~ric and voice mPss~ges can originate from a personal computer (PC) 420 via a modem. Alphanumeric mP~s~ges can also originate from a personal data assistant (PDA) 430, via a modem, and from a dedicated alphanumeric input device 440.
A message is transmitted to a mPss~ge subscriber unit (MSU) 500, only one of which is illustrated in FIG. 1 for simplicity. Each MSU 500 10 receives mP~s~Ps and in response thereto, tr~n~mit~ a response signal which is received by the ~y~ controller 300. Furthermore, the MSU 500 is a portable device, the size of a conventional pager, or sm~llPr, and is c~rriP~i by users throughout the MSCA 200. Thus, a MSU 500 is subscribed and entitled to receive messages in any cell of the MSCA 200. Due to the 15 mobility of the MSU 500, it is desirable, and a main thrust of the present invention is, to track the movement pattern of the MSU 500 so as to transmit a mP~c~ge in a cell where the MSU 500 is most likely located. The movement pattern is tracked and ~iefPrmine~l by monitoring in which cells the MSU 500 receives most mp~s~ges~ as will be explained in further 20 detail hereinafter.
Turning now to FIG. 2, a base station 220 is shown in ~,eaL~l detail.
The base station 220 cc,l~ ises a processor 222, a transmitter 224, a memory 226 and a receiver 228. The receiver 228 iS co-located with the transmitter 224 or optionally is located in another region of the cell. In 25 addition, there is optionally several receivers 228 associated with one base station, each arranged to cover a certain area of a cell. A receiver 228 not co-located with the base station 220 iS optionally directly connecte~l to the system controller 300. A cell with multiple rec~ive.~ 228 is useful because the tran~mitPr in the MSU 500 is a relatively low power tr~n~mittPr (thus 30 minimizing the power requir~mPnts of the MSU 500). While a detailed illustration of the base station 220 iS shown only in cell C1 in FIG. 2, it should be understood that cell C2 has a similar base station architecture, which would interact with the MSU 500 shown in cell C2.
Message requests which are received by the system controller 300 are 35 coupled to the base station 220 and stored in the memory 226 for processing by the processor 222. The transmitter 224 of the base station 220 periodically transmits a cell identifier (ID) signal which is received by an MSU so that the MSU can determine where it is located in the MSCA.
WO 97/03529 PCT/U~'.ÇGk'6 The transmitter 224 of the base station 220 also transmits mPssAges in the cell for reception by MSU's in the cell. The m~sAges contain address information, as is known in the field of paging, so that the meSsAge is received and decoded only by MSU's having a stored message subscriber unit address that matches the address transmitted with the message (individually addressed messAges or group address m~,cAges). The MSU
500 transmits a response signal to the base station in response to receiving a messA~e which is received by the transmitter 224.
The response signal takes on one of many types. When the MSU
10 500 receives a messAge and the signal carrying the message is of adequate quality, the response signal is a positive acknowle~gmf~nt or ACK. When the MSU 500 receives a m~sAge and the signal carrying the me~sAge is of poor quality, making accurate messAge decoding unlikely, then the response signal is a negative acknowle~1gm.ont called NACK. Other types 15 of response signals include responses to questions posed in messAges, such as YES, NO, and other nllm~ric, alphanllm~ric, graphical or short voice responses. Still another type of response signal is a registration signal which is generated in response to receiving a cell identifi~A*on signal, rihed in more detail hereinafter.
The base station tran~mitt~r 224 transmits radio frequency signals modulated with the information noted above, and receives radio frequency response signals transmitted by MSU's 500, such as those types of response signals described above. Messages destined for a particular MSU are associated with an address which matches an address stored in 25 the particular MSU. Thus, the MSU decodes a received radio frequency signal, detects whether its address is ~ Arrie-7 by the radio frequency signal, and decodes a mf~sA~e associated with the address if there is a match.
Addressed messA~es are known by the those with ordinary skill in the art of paging technology.
With refert:,lce to FIGS. 3 and 4, a general description of the process for managing communication in a two-way m~sA~e system is provided.
The flow charts and ~lesrription refer to a "particular" message subscriber unit as an example of when a meSsAge request is received for tran~mi~sicn to one of the multiple messA~e subscriber units in the system. It will be 35 apparent that certain steps in FIGS. 3 and 4 are being exPcllterl in parallelwith other steps. Th~r~fure, FIGS. 3 and 4 do not strictly represent a simple sequence of events.
WO 97/03529 PCT/u:~5~l~ GC~
Step 602 represents the establishment of a messaging system coverage area collL~lised of a plurality of cells. The me~ss~ge system coverage area is for example, the entire United States, or a particular region of multiple states, a single state, a single metropolitan area, etc.
Moreover, a single cell shown in FIGS. 1 and 2 is optionally a collection of cells that rl~fine~s a particular sub-coverage area within the overall m~ss~ging system coverage area. The single cell is used as an example for purposes of simplifying this description.
Step 604 represents the provision of a plurality of MSU's each being 10 capable of receiving me~ss~ges and tran~mitting response signals in response to receiving mPcs~ges. The response signal takes on one of the types described above.
In step 606, a base station is provided in a cell for transmitting me~ss~ges in each cell and for receiving response signals in each cell. As 15 will become apparent in conjunction with step 612, each base station also periodically transmits a cell i~l~ntifiPr signal.
In step 608, a system controller is provided to oversee commllnic~tion in the MSCA. CPA data for each MSU is stored in the memory of the system controller. The CPA data co~ l;ses a ~ref~lred cell 20 list made up of cell identifiers colle~onding to predetermined ones of cells in the m~ss~ging system coverage area where the corresponding MSU
most received mess~s. These "~ref~lled" cells are initially assigned by the service provider of the m~ssaging system and the user of the particular MSU when service is set up. For example, an initial assignment is the cell 25 where the user's office is located and the cell where the user's home is located. The cell identifiers for these two cells make up the initial entries of the ~r~felled cell list for that user's CPA data.
Additionally, in step 610, at the time of service set-up, the service provider stores the CPA data for that user into the MSU for that user. This 30 is done by known programming devices and methods.
Thereafter, the CPA data in the system controller and in the MSU
will be automatically updated/changed according to the mobility habits of the user. The remaining steps in FIGS. 3 and 4 explain how this is accomplished.
Step 612 represents that the base station periodically transmits a cell identifier signal in the corresponding cell. This signal is modulated on a frequency or freqll~n~ s to which the MSU's in the m~ss~ging system are tuned or are tunable, in order to enable a MSU to detect its location in the MSCA.
When an MSU receives a cell identifier signal, it is compared with the cell identifiers in the CPA data stored on-board. When the cell 5 identifier in the received cell identifier signal is not in the ~re~led cell list stored in the MSU, the MSU is outside of its CPA and transmits a registration signal as depicted in step 614. The registration signal is received by the receiver(s) associated with the base station in that cell where the MSU is located, and the base station relays this information to 10 the system controller, so as to register the location of the MSU based on which base station receiver best received (greatest signal strength) the registration signal from the MSU. Also, when the MSU re-enters the CPA
from a cell outside of the CPA, the MSU transmits a registration signal.
Step 616 represents reception of a mess~ge request, from the phone 410, PC 420, PDA 430 or alp~m-m~ric input device 440, for example, by the system controller 300. The m~s~ge request includes a message for a particular one of the MSU's in the m~s~ging ~y~lell~.
In step 618, the ~iy~ m controller ~let~rmines the location of the particular MSU before tr~n~mitting the me~sA~e. The location of the particular MSU is readily det~rmine~l if a recent registration signal has been received by a base station in the m~ ging :jy~ . Otherwise, the system controller refers to the CPA data stored for the particular MSU.
The process of determining the location of the particular MSU is described in ~;feal~l detail hereinafter in conjunction with FIG. 10.
In step 620, the mess~e for the particular MSU is trarl~mitte~l in the cell where the particular MSU is determined, in step 618, to be located.
When the particular MSU receives the m~s~ge, it transmits an a~ro~liate response signal, as indicated by step 622. In step 624, the response signal is received at by a receiver 228 and relayed to the system controller 300 so that the system controller 300 can update the CPA data for the particular MSU as it moves around the MSCA. When the MSU does not receive the m~s~ge that is transmitted in a cell, no response signal is received and a new cell in the CPA is chosen by the system controller for transmission of the me~s~e, until all cells in the CPA are tried, and failure is ultimately declared.
Referring to FIG. 5, the CPA data will be described. The CPA data comprises a preferred cell list for each MSU. The ~reLelled cell list is a list of cells where the MSU is located the most, based on acknowledgment of transmitted mPssAge~s or registration with a cell. As mentioned above, the CPA data is initially established at service set-up to be those cells where the user anticipates being located the most. However, after set-up and during use of the MSU, the mobility habits of the MSU are tracked and the CPA
5 data updated.
FIG. 5 is a "snapshot" at a particular instant of time of the CPA data for MSU1, MSU2 and MSU3. For MSU1, the CPA consists of cells C1, C2, C3 andC4; for MSU2, the CPA consists of cells C9, C10, C11 and C12; and for MSU3, its CPA consists of cell C4 and C9.
In order to establish when a cell is considered to be part of a ~r~L~lled cell list or CPA for an MSU, a usage index (UI) is established as a measure of usage of a cell for each MSU. Thus, the UI is a measure of probability that an MSU will receive a messA~e. For example, the UI
consists of the number of mPssAges received by the MSU in that cell or the 15 occurrence of a registration signal being tr~n.cmitte~l by the MSU for that cell, which are collectively referred .to as messAge receiving events. A cell is assigned to the plerelled cell list for an MSU when the number of mPccAges received by the MSU in that cell and the number of registration signals for that cell exceeds a predetermined threshold, called Thl. The UI
20 is normAli7e~ once the total number of received mPsc~ges for an MSU
exceeds a predetermined ma~imllm The ~reL,2l-ed cell list is a list of cells with UI > Thl and is arranged in descending order of UI's such that the first cell in the list is the one with the ~,~ealesl UI that is ~;leal~l than Thl.
A cell is removed from the cell list when, after normAli7~tion, the 25 UI is less than a prerlel~;.~ed minimL~n called Th2. Thus, when UI was before norm~li7Ation greater than Thl, but after normAli~ation less than Th2, that cell is removed from the ~r~Lt:lled cell list.
The thresholds Thl and Th2 are optionally different for individual MSU's. However, generally Thl is greater than or equal to Th2.
Referring to FIG. 6, a MSU 500 is shown in greater detail. The MSU
500 cu~ lises an antenna 502, a receiver 504, a decoder/controller 506, and a code plug memory 508 including an address memory 510 and a destination memory 512. A frequency synthesizer 514, which is optional, is coupled to the receiver 504 to adjust the tuning frequency of the receiver 504, under control of the decoder/controller 506. The code plug mPmory 508 is progr~mm~hle by a remote progrAmming device, as is well known in the art.
WO 97/03529 . PCT/US~ 6G~
- A tran~mit~r 516 is coupled to the decoder/controller 506 and the antenna 502 (or a different transmitt~r dedicated antenna not shown) to - transmit an acknowle~lgmPnt signal when a m~sAge is received. In addition, various alert devices are provided, such as the tactile alert 518 - 5 and the audible alert 520. A power switch 522 is also provided to activate and de-activate certain components of the MSU 500 under control of the decoder/controller 506.
User input into the selective call receiver is by way of selector switches 524 or graphical input device 528, both of which also interact with the decoder/controller 506 to generate certain response signals. Examples of graphical input device 528 are a touch screen input device, keyboard, virtual keyboard on touch screen input device, etc. Messages which are received by the MSU 500 are displayed on the display 526 FIG. 7 illustrates the decoder/controller 506 in greater detail. At its heart, the decoder/controller 506 comprises a central processing unit 700 which processes software instructions stored in a ROM 702 and/or RAM
704. Data flow into and out of the decoder/controller 506 is controlled by input/output (I/O) ports 706 and 708. A timer counter 710 is connected to the oscillator 712 for certain timing functions. The central processing unit drives the display 526 via a display driver 714. An alert generator 716 generates triggering signals for the alert devices, such as the audible alert 520 and tactile alert 518 shown in FIG. 6. The various components of the central processing unit 700 communicate over the bus 718.
Firmware for executing processing received messages, evaluating quality of received signals and generating response signals (along with other functions) is stored in the ROM 702 or RAM 704 and executed by the central processing unit 700. The CPA data for the MSU is initially stored in the RAM 704, for example, of the MSU 500, and then updates to the CPA data are made on the basis of signals received by the receiver 504 and processed by the decoder/controller 506.
Turning now to the flow charts of FIGS. 8-12, the details of how CPA data of an MSU is updated will be described. FIGS. 8, 10, 11 and 12 are procedures performed in the system controller 300 and FIGS. 9 and 13 are procedures performed in the MSU.
FIG. 8 illustrates the main operating procedure in the system controller 300. Initially, in step 800, a m~Age request for an MSU is received by the system controller 300. The system controller in step 810 WO 97/03529 PCT/u~ _ 'i.'. 6 locates the MSU. The procedure for located the MSU is shown in FIG. 10, which is described hereinafter.
When a location of the MSUis determined from step 810, it is del~, ...i..~ in step 820 whether a CPA updating m~ssAge is due to be transmitted to the MSU. If not, then the procedure jumps to step 840.
When there is a CPA updating m~CcAge to be trancmitte~, then in step 830, the CPA updating messAge is transmitte-l with or "piggybacked" the requested meSsAge that was received by the system controller 300 for transmission to the MSU. In step 840, the m~ssAge is coupled to the base station where the MSUis ~etf~rmined to be located, with or without the CPA updating m~C.cA~e as the case may be, for trancmissi(-n to the MSU.
Next, in step 850, the system controller waits to receive a response signal, spe~ if icAlly a positive acknowle~lgment signal ACK from the MSU, via the receiver associated with the base station that receives the ACK. If an ACK is not received, then the procedure jumps to step 870. Otherwise, if an ACK is received, then in step 860, a mark (Ml or M2) associated with a cell is removed, if one exists, and the cell associated with the mark is added or ~lete~l from the CPA for that MSU in the system controller 300.
The marks Ml and M2 are used to confirm updating the CPA data in the system controller, and will be described in further detail hereinafter.
In step 870, the usage index and CPA data for the MSU are updated in the system controller 300. In addition, the current location of the MSU, as det~rminPtl in step 810,is also updated in step 870.
Turning to FIG. 10, the procedure for locating an MSU will be ri~crrihed. In step 812, the system controller 3oo~1et~ormines whether it has current location information available regarding reception of a registration signal which indicates that the MSU left its CPA and thus has trAn~mitterl a registration signal to the system. A registration signal received from an MSU which just re-entered its CPA is not used a current location information in step 812 because the MSU may have moved to a new cell in the CPA which is dif~~ t from the cell where the MSU
initially re-entered *s CPA. When the system controller receives a registration signal for a cell outside its CPA, it registers the MSU for service in that cell outside the CPA and stores this cell as a current location for the MSU, should a m~scAge request be received for trAnsmitting a mPCsAge to that MSU. If the system controller 300 has such informAti--n available for the MSU, then that cell from which the registration signal was received is sel~cte~l for traI cmicsion of a m-ossA~e (FIG. 8).
CA 02226446 l998-0l-07 W O 97/03529 PCT~USS-'66~6 Otherwise, in step 814, when no current location information on the MSU is available in the system controller 300 searches its CPA
memory in order to select a cell in the preferred cell list of the CPA for the MSU. The cell with the highest priority of usage, is chosen first. The cell with the highest priority in the CPA is the one with the highest usage index (described hereinafter) or alternatively is the cell where the last m~s~ge was received by the MSU or the cell where the MSU re-entered its CPA and transmitted a registration signal.
In step 816, the ~y~L~ controller 300 causes a location confirming 10 signal which is addressed to the MSU (a "where are you" signal) to be transmitted by the base station in the cell of highest priority in the preferred cell list for the MSU. If the MSU acknowledges receipt of this signal with either an ACK or NACK in step 818, the location of the MSU is confirmed to be in that particular cell. Otherwise, the cell in the ~rerelled cell list with the next highest priority is chosen for transmi~sicn of the location confirming signal, and the process repeats at steps 814-818 through all cells in the CPA of the MSU until the MSU responds with a response signal (ACK or NACK), or does not respond at all after exhausting the cells listed in the ~rer~l-ed cell list, in which case the location procedure fails.
In steps 814 and 816, it is envisioned that a location confirming signal is tra~mitte~ cell-by-cell in descending order of priority in the ~re~lled cell list and waiting for a response signal from the MSU in each cell, or that a location confirming signal is tra~mitte~l independently in all of the cells (or geographically separated cells considering effects of illL~ llce between cells) of the CPA for the MSU without waiting for reception of a response signal from each cell.
Thus, registration of a particular MSU involves transmitting a registration signal from the particular m~ss~ge subscriber unit when the particular message subscriber unit leaves its customer paging area as determined in response to receiving a cell identifier signal having a cell identifier corresponding to a cell which is not in its customer paging area when a previously received cell identifier signal had a cell identifier corresponding to a cell inside the customer paging area of the particular message subscriber unit, or when the particular message subscriber unit is outside its customer paging area and ~1et~rminf~ that it is in a new cell in response to receiving a cell identifier signal having a cell identifier different from a cell identifier in a previously received cell identifier WO 97/035~9 PCT/US96/06686 signal; and receiving the registration signal in the cell outside the customer paging area of the particular mP~s~ge subscriber unit and relaying the registration signal to the system controller for registering and storing a location for the particular m~s~ge subscriber unit.
In sum, there are levels of priority according to which a cell is chosen for trangmiggiQn of a m~gs~ge. The highest priority level is when there is current location information for an MSU which has left its CPA, in which case a registration signal was transmitted by the MSU and stored with the system controller to identify that cell outside the CPA. The next highest priority level is when no registration information is found in the ~y~ controller and the CPA data is used. The first cell chosen in the CPA is either the one with the highest usage index, or alternatively is the one where the MSU most recently received a messAge or the cell where the MSU just re-entered its CPA. Thereafter, cells with lower priorities in the CPA are used until exhausted and no reply to the location confirming signal is made.
The procedure for updating the usage index and CPA data in the ~iy~ l controller is shown in FIG. 11. In step 872, if the mPcs~ge trancmitte-l in step 840 is acknowledged in step 850 or a registration signal is received for an MSU, the UI for the cell in which the mPgs~ge was tra~mitte~l and acknowledged, or the registration signal received, is incremented. Thus, the usage index represents a number of m~ss~ge receiving events by a me~gg~ge subscriber unit ~n each cell. In addition, a occurrence counter is incremented. Next, in step 874, it is determined whether the UI for that cell is greater than a first predetermined threshold Thl under the condition that at the last iteration or update the UI for that cell was less than or equal to the first predetermined threshold Thl.
When it is determined in step 874 that the UI for a cell exceeds the first predetf~rmin~ threshold Thl when at the last update it was not, then cell is marked with an addition mark M2. The addition mark M2 indicates that the system controller is planning to add the cell to the CPA for that MSU, but will wait until the MSU has ~ onfirme~ reception of a CPA
update mf~cs~ge which instructs the MSU to add that cell to its CPA. Thus, the CPA data in the ~y:.lelll controller and the MSU will match because the system controller updates its CPA data for the MSU only when it receives acknowle~gm~nt that the MSU received the CPA updated m~gs~ge.
In step 878, when the counter exceeds a predet~rminel1 maximum number of total m~gs~ge receiving events (including acknowledged CA 02226446 l998-0l-07 WO 97/035~9 PCT/US96/06686 mess~ges and registration signals) Nmax, then in step 880, the UI's are norm~li7e~l or scaled down a~ropliately and the counter is reset. In step 882, after the norm~li7~tion of step 880, the UI for each cell is compared with a second predetermined threshold Th2 to determine if it is less than 5 or equal to the second predetermined threshold Th2, when before norm~li7~tion, UI for the cell was greater than the second predetermined threshold Th2. If the UI for the cell is less than the threshold Th2 when before normalization the UI was greater than the threshold Th2, the cell is marked with a deletion mark M1. The deletion mark M1 indicates that 10 the system controller is planning to delete the cell from the CPA for that MSU, but that the MSU has not yet confirm~l reception of a CPA update message which instructs the MSU to delete the cell from its CPA.
Referring back to FIG. 8, the system controller removes the mark M1 or M2 associated with a cell when the system controller receives an 15 ACK signal, indicating that the MSU receives the requested mP~ss~ge and the CPA update mes~ge. The cell is then either added or deleted from the CPA accordingly in the system controller 300.
Thus, the CPA update procedure of FIG. 11 has a hy~lere~is characteristic in that a cell, once added to the CPA,is not imme~ tely 20 deleted from the CPA once its UI drops significantly. Rather, it is a very adaptive and gradual process. The value of Nmax is chosen to not be too big so as to be too slow in responding to changes. Its value is optionally different for light users versus heavy users in the system. The first predetermined threshold Thl and the second predetermined threshold 25 Th2 are chosen to provide a stable tracking of the CPA data without substantial oscillation.
FIG. 12 illustrates how the system controller processes reception of a registration signal from an MSU. In step 900, the system controller receives the registration signal relayed to it by the cell-located receiver that30 received it. In step 902, the CPA and UI are updated by the same procedure shown in FIG. 11 when a registration signal is received. In addition, in step 902, the ~y~L~ controller 300 stores a current location of the MSU
based on in which cell the MSU most recently received a message and acknowledged reception of the message. This is useful in determining 35 which cell in the CPAis first chosen for tran~mi~sion of a location confirming signal for the next m~s~ge request, explained above in conjunction with step 814 in FIG. 10.
CA 02226446 l998-0l-07 Referring to FIGS. 9 and 13, the procedures by which an MSU
processes CPA updating information and other sign~l~ is described. In FIG. 9, the MSU receives a mesS~ge in step 1000. The m~s~ge referred to in step 1000 is a data mess~e, voice m-~s~ge, or graphics m~s~ge, etc., which is created by a party via the input devices 410-440, for example, shown in FIG. 1. In step 1002, the MSU determines whether the quality of the received m~sAge is sati~f~c~tory and reliable. When the meSsAge received is not of s~tisf~ctory or reliable quality, then a NACK response signal is tran~mitte~l by the MSU in step 1010. This may be followed up by 10 a repeat tran~mi~ion of the m~s~ge to the MSU by the ~y~Lel~- controller 300.
When the quality of the received mP~s~e is s~lffi~ nt, then in step 1004, it is rle~rmined whether a CPA update m~ss~e is attached to the m~csAge. When a CPA update ml~s~ge exists with the received mPss~ge, 15 the CPA data stored in the MSU is updated in step 1006 accordingly. For example, the CPA update m~s~ge informs the MSU to add a particular cell, such as cell C5, to the ~rer~lled cell list. When no CPA updating m~s~ge accompanies the m~oss~ge~ step 1006 is bypassed and an ACK
signal is tran~mitte-i by the MSU in step 1008.
In FIG. 13, step 1020 the MSU is periodically ~1et~rmines its location in the MSCA by comparing a received cell identifier signal with its stored CPA. When a predetPrmine~ period of time expires in step 1022, the MSU
determines in step 1024 whether it was in a cell that is within its CPA at the previous ~iet~ormination~ If it was within its CPA at the previous 25 activation period, then in step 1026, the MSU det~rmin~ whether it is cull~lllly within its CPA. If the MSU ~et~ormines that it is still in its CPA
in step 1026, then there is no need to transmit a registration signal and the MSU can return to its normal listening mode during which it detects its address in a tr~n~mitte.l signal in a cell.
When the MSU determines in step 1024 that it was outside its CPA
at the previous determination or was inside its CPA at the previous determination, but at the present ~ielP...,i.l~tion is no longer inside the CPA (step 1026), then in step 1028, it determines whether the cell idf-ntifiPr signal transmitted in the cell corresponds to a new cell (different from the 35 cell outside the CPA at the previous determination) which is also outside its CPA or whether it is in a cell which is inside its CPA. In step 1028, when the cell i~ntifier signal received by the MSU corresponds to a cell outside the CPA different from the non-CPA at the previous CA 02226446 l998-0l-07 determination, then the MSU transmits a location registration signal in step 1030. On the other hand, when the MSU has not moved to a different - non-CPA cell, then a location registration signal is not transmitted because there is no new location information to report. Furthermore, when the 5 cell identifier signal received by the MSU corresponds to a cell inside the CPA, then this indicates that the MSU has moved back into its CPA and in step 1030 the MSU transmits a location registration signal. Thus, whenever the MSU moves out of its CPA it transmits a registration signal, and whenever the MSU moves to a different cell outside its CPA, it 10 transmits a registration signal.
The location registration signal transmitted in step 1030 is, for example, a signal which i-1~ntifie~s the MSU which transmits it and also identifies (by address) the cell from which it is transmitted. Thus, the system controller 300, by receiving a registration signal, knows which 15 MSU transmitte~l it, and from which cell the signal was transmitted.
The procedures of FIGS. 9 and 13 are implemented, for example, by firmware stored in the ROM 702 or software stored in the RAM 704 of the MSU.
A particular advantage of the present invention is that the majority 20 of the "intelligence" for locating an MSU and tracking the mobility pattern of the MSU in the MSCA, is in the system controller. The MSU merely stores the ~rt ~lled cell list, which is updated by the system controller with the next tra~smission of a m~ss~ge to the MSU. Furthermore, updating of the CPA data in the MSU is achieved with minimal additional "air time"
25 because the CPA update me~ss~ge is transmitted with the next mess~ge to be sent to the MSU.
The above description is intended by way of example only and is not intended to limit the present il~v~l~lion in any way except as set forth in the following rl~ims What is ~ ime-1 is:
SYSTEM AND METHOD T~:IF.~FFOR
Field of the Invention The present invention is directed to a two-way mPss~ging system, and more particularly to a method and apparatus for efficiently managing system capacity with minimal system complexity and optimal battery power utilization in a subscriber unit.
Background of the Invention Paging systems have evolved into more robust communication systems capable of transmitting alphanllmPric, voice and image data to 15 portable receivers. Two-way paging systems are on the horizon. In a two-way paging system, the portable device transmits a limited content response signal which i~ lPs a reply mpssage or an acknowlPfi~nPnt message in response to receiving a mP~sSage. Thus, the term "mP~ssaging is a broader term which encompasses the transmi~sion of data messages, 20 voice messages, fa~ similP mP~s~ges, etc., as well as col,L~ln~lating the transmissiQn back from the portable or remote unit of a response signal which is a reply mPss~ge or an acknowlellgmPnt message.
A mes~ging system comprising a plurality of message subscriber units (capable of receiving mPss~ges and transmitted response signals) will 25 accommodate a variety of mPssage types, some which require more "air-time", such as data mPss~ges and fa~ simile mf~ss~, than others. The challenge is to optimize the tran~mi~sion of mp~ss~ges to message subscriber units so as to maintain a high system capacity. Part of this challenge involves transmitting mPss~ges only in those portions of a 30 mPss~ging system coverage area where the meSsage subscriber unit is likely to be located.
~ Brief Description of the Dldwil~S
FIG. 1 is an P1Pctri~ al block diagram illustrating the two-way mP~ss~ging system according to a ~re~lled embodiment of the present invention.
CA 02226446 l998-Ol-Oi FIG. 2 is an ~ ctric~l block diagram illustrating a base station and a mf~S~ge subscriber unit, and commtlnication there between according to the present invention.
FIGS. 3 and 4 are flow charts which generally illustrate the method of managing communication of a two-way me~ ing system according to the preferred embodiment of the present invention.
FIG. 5 is a diagram showing a m~oscAging system coverage area and 10 the dyn~mi~lly changing customer paging areas associated with mess~ge subscriber units in the two-way m~s~gin~ system according to the preferred embodiment of the present invf~ntion FIG. 6 is an electri~l block diagram of a mP~s~ge subscriber un*
15 according to the ~ref~lled embodiment of the present invention.
FIG. 7 is an ~l~ctricAl block diagram of a decoder/controller of a m~s~ge subscriber unit according to the ~rer~ d embodiment of the present invention.
FIG. 8 is a flow chart which illustrates a procedure for receiving a mess~ge request and tran.Cii~ g a mPs~ge to a message subscriber unit according to the ~refelled embo~lim~nt of the present il-v~l~Lion.
FIG. 9 is a flow chart which illustrates a procedure by which a mf~s~ge subscriber unit receives and acknowledges a mpss~e according to the ~re~.led embodiment of the present invention.
FIG. 10 is a flow chart which illustrates a procedure for determining 30 a location of a m~s~ge subscriber unit according to the ~reLelled embodiment of the present invention.
FIG. 11 is a flow chart which illustrates a procedure for updating customer paging area data according to the ~reLeLled embodiment of the 35 present invention.
WO 97/03529 PCT/U.,~ 6C~6 FIG. 12 is a flow chart illustrating a procedure in messAge subscriber unit for registering a location which leaves its customer paging area ~ according to the preferred embodiment of the present invention.
FIG. 13 is a flow chart illustrating a procedure for processing a registration signal from a m~c~Age subscriber unit which leaves its customer paging area according to the ~reLlred embodiment of the present invention.
DetAil~l Description of the Dldwil~gs FIG. 1 illustrates a two-way mP~sAging system according to the present invention. The messAging system 100 is designed to provide commun~ation throughout a m~sAging ~y~leln coverage area (MSCA) 200. The MSCA 200 cull,ylises a plurality of cells 210, and each cell comprises a base station 220 and at least one antenna 230. FIG. 1 shows that there are 12 cells, numbered C1-C12 each with a base station BS1-BS12;
however it should be understood that 12 cells is only an example and that the MSCA 200 can cc,ll-ylise any numbered of cells as is ~c~sAry to provide coverage within a me~cAging system. Moreover, the cells do not cf~ rily have the geometric conAguration shown in FIG. 1. Multiple cells are grouped into a zone such that zone 1 comprises cells C1, C5 and C9, zone 2 comylises cells C2, C3, C6, C7, C10 and C11, and zone 3 ccll,ylises cells C4, C8 and C12.
A system controller 300 is coupled to each base station 220 and oversees control of communication throughout the MSCA 200. The system controller 300 colllylises a m~sAge memory 310, a customer paging area (CPA) memory 320 and a processor 330. Message requests are received by the system controller 300 through the public telephone system network (PTSN) 400 and are stored in the mes~Age memory 310 for processing. The CPA memory is for storing customer paging area data as well as for storing location registration information concerning each subscriber unit in the system, which is explained in greater detail hereinafter. Messages are also passed to the system controller 300 through electronic-mail networks including the Internet.
Depending on the size of a MSCA and the number of cells therein, there are more than one ~yble,ll controller for the MSCA, each being ~e~icAte~ to a particular subset of cells.
CA 02226446 l998-0l-07 Message requests can originate from one of many types of sources, of which PIG. 1 illustrates a few as examples. NllmPric and voice mps~ges can originate from a conventional handset phone 410 (wired or wireless).
Alph~nllm~ric and voice mPss~ges can originate from a personal computer (PC) 420 via a modem. Alphanumeric mP~s~ges can also originate from a personal data assistant (PDA) 430, via a modem, and from a dedicated alphanumeric input device 440.
A message is transmitted to a mPss~ge subscriber unit (MSU) 500, only one of which is illustrated in FIG. 1 for simplicity. Each MSU 500 10 receives mP~s~Ps and in response thereto, tr~n~mit~ a response signal which is received by the ~y~ controller 300. Furthermore, the MSU 500 is a portable device, the size of a conventional pager, or sm~llPr, and is c~rriP~i by users throughout the MSCA 200. Thus, a MSU 500 is subscribed and entitled to receive messages in any cell of the MSCA 200. Due to the 15 mobility of the MSU 500, it is desirable, and a main thrust of the present invention is, to track the movement pattern of the MSU 500 so as to transmit a mP~c~ge in a cell where the MSU 500 is most likely located. The movement pattern is tracked and ~iefPrmine~l by monitoring in which cells the MSU 500 receives most mp~s~ges~ as will be explained in further 20 detail hereinafter.
Turning now to FIG. 2, a base station 220 is shown in ~,eaL~l detail.
The base station 220 cc,l~ ises a processor 222, a transmitter 224, a memory 226 and a receiver 228. The receiver 228 iS co-located with the transmitter 224 or optionally is located in another region of the cell. In 25 addition, there is optionally several receivers 228 associated with one base station, each arranged to cover a certain area of a cell. A receiver 228 not co-located with the base station 220 iS optionally directly connecte~l to the system controller 300. A cell with multiple rec~ive.~ 228 is useful because the tran~mitPr in the MSU 500 is a relatively low power tr~n~mittPr (thus 30 minimizing the power requir~mPnts of the MSU 500). While a detailed illustration of the base station 220 iS shown only in cell C1 in FIG. 2, it should be understood that cell C2 has a similar base station architecture, which would interact with the MSU 500 shown in cell C2.
Message requests which are received by the system controller 300 are 35 coupled to the base station 220 and stored in the memory 226 for processing by the processor 222. The transmitter 224 of the base station 220 periodically transmits a cell identifier (ID) signal which is received by an MSU so that the MSU can determine where it is located in the MSCA.
WO 97/03529 PCT/U~'.ÇGk'6 The transmitter 224 of the base station 220 also transmits mPssAges in the cell for reception by MSU's in the cell. The m~sAges contain address information, as is known in the field of paging, so that the meSsAge is received and decoded only by MSU's having a stored message subscriber unit address that matches the address transmitted with the message (individually addressed messAges or group address m~,cAges). The MSU
500 transmits a response signal to the base station in response to receiving a messA~e which is received by the transmitter 224.
The response signal takes on one of many types. When the MSU
10 500 receives a messAge and the signal carrying the message is of adequate quality, the response signal is a positive acknowle~gmf~nt or ACK. When the MSU 500 receives a m~sAge and the signal carrying the me~sAge is of poor quality, making accurate messAge decoding unlikely, then the response signal is a negative acknowle~1gm.ont called NACK. Other types 15 of response signals include responses to questions posed in messAges, such as YES, NO, and other nllm~ric, alphanllm~ric, graphical or short voice responses. Still another type of response signal is a registration signal which is generated in response to receiving a cell identifi~A*on signal, rihed in more detail hereinafter.
The base station tran~mitt~r 224 transmits radio frequency signals modulated with the information noted above, and receives radio frequency response signals transmitted by MSU's 500, such as those types of response signals described above. Messages destined for a particular MSU are associated with an address which matches an address stored in 25 the particular MSU. Thus, the MSU decodes a received radio frequency signal, detects whether its address is ~ Arrie-7 by the radio frequency signal, and decodes a mf~sA~e associated with the address if there is a match.
Addressed messA~es are known by the those with ordinary skill in the art of paging technology.
With refert:,lce to FIGS. 3 and 4, a general description of the process for managing communication in a two-way m~sA~e system is provided.
The flow charts and ~lesrription refer to a "particular" message subscriber unit as an example of when a meSsAge request is received for tran~mi~sicn to one of the multiple messA~e subscriber units in the system. It will be 35 apparent that certain steps in FIGS. 3 and 4 are being exPcllterl in parallelwith other steps. Th~r~fure, FIGS. 3 and 4 do not strictly represent a simple sequence of events.
WO 97/03529 PCT/u:~5~l~ GC~
Step 602 represents the establishment of a messaging system coverage area collL~lised of a plurality of cells. The me~ss~ge system coverage area is for example, the entire United States, or a particular region of multiple states, a single state, a single metropolitan area, etc.
Moreover, a single cell shown in FIGS. 1 and 2 is optionally a collection of cells that rl~fine~s a particular sub-coverage area within the overall m~ss~ging system coverage area. The single cell is used as an example for purposes of simplifying this description.
Step 604 represents the provision of a plurality of MSU's each being 10 capable of receiving me~ss~ges and tran~mitting response signals in response to receiving mPcs~ges. The response signal takes on one of the types described above.
In step 606, a base station is provided in a cell for transmitting me~ss~ges in each cell and for receiving response signals in each cell. As 15 will become apparent in conjunction with step 612, each base station also periodically transmits a cell i~l~ntifiPr signal.
In step 608, a system controller is provided to oversee commllnic~tion in the MSCA. CPA data for each MSU is stored in the memory of the system controller. The CPA data co~ l;ses a ~ref~lred cell 20 list made up of cell identifiers colle~onding to predetermined ones of cells in the m~ss~ging system coverage area where the corresponding MSU
most received mess~s. These "~ref~lled" cells are initially assigned by the service provider of the m~ssaging system and the user of the particular MSU when service is set up. For example, an initial assignment is the cell 25 where the user's office is located and the cell where the user's home is located. The cell identifiers for these two cells make up the initial entries of the ~r~felled cell list for that user's CPA data.
Additionally, in step 610, at the time of service set-up, the service provider stores the CPA data for that user into the MSU for that user. This 30 is done by known programming devices and methods.
Thereafter, the CPA data in the system controller and in the MSU
will be automatically updated/changed according to the mobility habits of the user. The remaining steps in FIGS. 3 and 4 explain how this is accomplished.
Step 612 represents that the base station periodically transmits a cell identifier signal in the corresponding cell. This signal is modulated on a frequency or freqll~n~ s to which the MSU's in the m~ss~ging system are tuned or are tunable, in order to enable a MSU to detect its location in the MSCA.
When an MSU receives a cell identifier signal, it is compared with the cell identifiers in the CPA data stored on-board. When the cell 5 identifier in the received cell identifier signal is not in the ~re~led cell list stored in the MSU, the MSU is outside of its CPA and transmits a registration signal as depicted in step 614. The registration signal is received by the receiver(s) associated with the base station in that cell where the MSU is located, and the base station relays this information to 10 the system controller, so as to register the location of the MSU based on which base station receiver best received (greatest signal strength) the registration signal from the MSU. Also, when the MSU re-enters the CPA
from a cell outside of the CPA, the MSU transmits a registration signal.
Step 616 represents reception of a mess~ge request, from the phone 410, PC 420, PDA 430 or alp~m-m~ric input device 440, for example, by the system controller 300. The m~s~ge request includes a message for a particular one of the MSU's in the m~s~ging ~y~lell~.
In step 618, the ~iy~ m controller ~let~rmines the location of the particular MSU before tr~n~mitting the me~sA~e. The location of the particular MSU is readily det~rmine~l if a recent registration signal has been received by a base station in the m~ ging :jy~ . Otherwise, the system controller refers to the CPA data stored for the particular MSU.
The process of determining the location of the particular MSU is described in ~;feal~l detail hereinafter in conjunction with FIG. 10.
In step 620, the mess~e for the particular MSU is trarl~mitte~l in the cell where the particular MSU is determined, in step 618, to be located.
When the particular MSU receives the m~s~ge, it transmits an a~ro~liate response signal, as indicated by step 622. In step 624, the response signal is received at by a receiver 228 and relayed to the system controller 300 so that the system controller 300 can update the CPA data for the particular MSU as it moves around the MSCA. When the MSU does not receive the m~s~ge that is transmitted in a cell, no response signal is received and a new cell in the CPA is chosen by the system controller for transmission of the me~s~e, until all cells in the CPA are tried, and failure is ultimately declared.
Referring to FIG. 5, the CPA data will be described. The CPA data comprises a preferred cell list for each MSU. The ~reLelled cell list is a list of cells where the MSU is located the most, based on acknowledgment of transmitted mPssAge~s or registration with a cell. As mentioned above, the CPA data is initially established at service set-up to be those cells where the user anticipates being located the most. However, after set-up and during use of the MSU, the mobility habits of the MSU are tracked and the CPA
5 data updated.
FIG. 5 is a "snapshot" at a particular instant of time of the CPA data for MSU1, MSU2 and MSU3. For MSU1, the CPA consists of cells C1, C2, C3 andC4; for MSU2, the CPA consists of cells C9, C10, C11 and C12; and for MSU3, its CPA consists of cell C4 and C9.
In order to establish when a cell is considered to be part of a ~r~L~lled cell list or CPA for an MSU, a usage index (UI) is established as a measure of usage of a cell for each MSU. Thus, the UI is a measure of probability that an MSU will receive a messA~e. For example, the UI
consists of the number of mPssAges received by the MSU in that cell or the 15 occurrence of a registration signal being tr~n.cmitte~l by the MSU for that cell, which are collectively referred .to as messAge receiving events. A cell is assigned to the plerelled cell list for an MSU when the number of mPccAges received by the MSU in that cell and the number of registration signals for that cell exceeds a predetermined threshold, called Thl. The UI
20 is normAli7e~ once the total number of received mPsc~ges for an MSU
exceeds a predetermined ma~imllm The ~reL,2l-ed cell list is a list of cells with UI > Thl and is arranged in descending order of UI's such that the first cell in the list is the one with the ~,~ealesl UI that is ~;leal~l than Thl.
A cell is removed from the cell list when, after normAli7~tion, the 25 UI is less than a prerlel~;.~ed minimL~n called Th2. Thus, when UI was before norm~li7Ation greater than Thl, but after normAli~ation less than Th2, that cell is removed from the ~r~Lt:lled cell list.
The thresholds Thl and Th2 are optionally different for individual MSU's. However, generally Thl is greater than or equal to Th2.
Referring to FIG. 6, a MSU 500 is shown in greater detail. The MSU
500 cu~ lises an antenna 502, a receiver 504, a decoder/controller 506, and a code plug memory 508 including an address memory 510 and a destination memory 512. A frequency synthesizer 514, which is optional, is coupled to the receiver 504 to adjust the tuning frequency of the receiver 504, under control of the decoder/controller 506. The code plug mPmory 508 is progr~mm~hle by a remote progrAmming device, as is well known in the art.
WO 97/03529 . PCT/US~ 6G~
- A tran~mit~r 516 is coupled to the decoder/controller 506 and the antenna 502 (or a different transmitt~r dedicated antenna not shown) to - transmit an acknowle~lgmPnt signal when a m~sAge is received. In addition, various alert devices are provided, such as the tactile alert 518 - 5 and the audible alert 520. A power switch 522 is also provided to activate and de-activate certain components of the MSU 500 under control of the decoder/controller 506.
User input into the selective call receiver is by way of selector switches 524 or graphical input device 528, both of which also interact with the decoder/controller 506 to generate certain response signals. Examples of graphical input device 528 are a touch screen input device, keyboard, virtual keyboard on touch screen input device, etc. Messages which are received by the MSU 500 are displayed on the display 526 FIG. 7 illustrates the decoder/controller 506 in greater detail. At its heart, the decoder/controller 506 comprises a central processing unit 700 which processes software instructions stored in a ROM 702 and/or RAM
704. Data flow into and out of the decoder/controller 506 is controlled by input/output (I/O) ports 706 and 708. A timer counter 710 is connected to the oscillator 712 for certain timing functions. The central processing unit drives the display 526 via a display driver 714. An alert generator 716 generates triggering signals for the alert devices, such as the audible alert 520 and tactile alert 518 shown in FIG. 6. The various components of the central processing unit 700 communicate over the bus 718.
Firmware for executing processing received messages, evaluating quality of received signals and generating response signals (along with other functions) is stored in the ROM 702 or RAM 704 and executed by the central processing unit 700. The CPA data for the MSU is initially stored in the RAM 704, for example, of the MSU 500, and then updates to the CPA data are made on the basis of signals received by the receiver 504 and processed by the decoder/controller 506.
Turning now to the flow charts of FIGS. 8-12, the details of how CPA data of an MSU is updated will be described. FIGS. 8, 10, 11 and 12 are procedures performed in the system controller 300 and FIGS. 9 and 13 are procedures performed in the MSU.
FIG. 8 illustrates the main operating procedure in the system controller 300. Initially, in step 800, a m~Age request for an MSU is received by the system controller 300. The system controller in step 810 WO 97/03529 PCT/u~ _ 'i.'. 6 locates the MSU. The procedure for located the MSU is shown in FIG. 10, which is described hereinafter.
When a location of the MSUis determined from step 810, it is del~, ...i..~ in step 820 whether a CPA updating m~ssAge is due to be transmitted to the MSU. If not, then the procedure jumps to step 840.
When there is a CPA updating m~CcAge to be trancmitte~, then in step 830, the CPA updating messAge is transmitte-l with or "piggybacked" the requested meSsAge that was received by the system controller 300 for transmission to the MSU. In step 840, the m~ssAge is coupled to the base station where the MSUis ~etf~rmined to be located, with or without the CPA updating m~C.cA~e as the case may be, for trancmissi(-n to the MSU.
Next, in step 850, the system controller waits to receive a response signal, spe~ if icAlly a positive acknowle~lgment signal ACK from the MSU, via the receiver associated with the base station that receives the ACK. If an ACK is not received, then the procedure jumps to step 870. Otherwise, if an ACK is received, then in step 860, a mark (Ml or M2) associated with a cell is removed, if one exists, and the cell associated with the mark is added or ~lete~l from the CPA for that MSU in the system controller 300.
The marks Ml and M2 are used to confirm updating the CPA data in the system controller, and will be described in further detail hereinafter.
In step 870, the usage index and CPA data for the MSU are updated in the system controller 300. In addition, the current location of the MSU, as det~rminPtl in step 810,is also updated in step 870.
Turning to FIG. 10, the procedure for locating an MSU will be ri~crrihed. In step 812, the system controller 3oo~1et~ormines whether it has current location information available regarding reception of a registration signal which indicates that the MSU left its CPA and thus has trAn~mitterl a registration signal to the system. A registration signal received from an MSU which just re-entered its CPA is not used a current location information in step 812 because the MSU may have moved to a new cell in the CPA which is dif~~ t from the cell where the MSU
initially re-entered *s CPA. When the system controller receives a registration signal for a cell outside its CPA, it registers the MSU for service in that cell outside the CPA and stores this cell as a current location for the MSU, should a m~scAge request be received for trAnsmitting a mPCsAge to that MSU. If the system controller 300 has such informAti--n available for the MSU, then that cell from which the registration signal was received is sel~cte~l for traI cmicsion of a m-ossA~e (FIG. 8).
CA 02226446 l998-0l-07 W O 97/03529 PCT~USS-'66~6 Otherwise, in step 814, when no current location information on the MSU is available in the system controller 300 searches its CPA
memory in order to select a cell in the preferred cell list of the CPA for the MSU. The cell with the highest priority of usage, is chosen first. The cell with the highest priority in the CPA is the one with the highest usage index (described hereinafter) or alternatively is the cell where the last m~s~ge was received by the MSU or the cell where the MSU re-entered its CPA and transmitted a registration signal.
In step 816, the ~y~L~ controller 300 causes a location confirming 10 signal which is addressed to the MSU (a "where are you" signal) to be transmitted by the base station in the cell of highest priority in the preferred cell list for the MSU. If the MSU acknowledges receipt of this signal with either an ACK or NACK in step 818, the location of the MSU is confirmed to be in that particular cell. Otherwise, the cell in the ~rerelled cell list with the next highest priority is chosen for transmi~sicn of the location confirming signal, and the process repeats at steps 814-818 through all cells in the CPA of the MSU until the MSU responds with a response signal (ACK or NACK), or does not respond at all after exhausting the cells listed in the ~rer~l-ed cell list, in which case the location procedure fails.
In steps 814 and 816, it is envisioned that a location confirming signal is tra~mitte~ cell-by-cell in descending order of priority in the ~re~lled cell list and waiting for a response signal from the MSU in each cell, or that a location confirming signal is tra~mitte~l independently in all of the cells (or geographically separated cells considering effects of illL~ llce between cells) of the CPA for the MSU without waiting for reception of a response signal from each cell.
Thus, registration of a particular MSU involves transmitting a registration signal from the particular m~ss~ge subscriber unit when the particular message subscriber unit leaves its customer paging area as determined in response to receiving a cell identifier signal having a cell identifier corresponding to a cell which is not in its customer paging area when a previously received cell identifier signal had a cell identifier corresponding to a cell inside the customer paging area of the particular message subscriber unit, or when the particular message subscriber unit is outside its customer paging area and ~1et~rminf~ that it is in a new cell in response to receiving a cell identifier signal having a cell identifier different from a cell identifier in a previously received cell identifier WO 97/035~9 PCT/US96/06686 signal; and receiving the registration signal in the cell outside the customer paging area of the particular mP~s~ge subscriber unit and relaying the registration signal to the system controller for registering and storing a location for the particular m~s~ge subscriber unit.
In sum, there are levels of priority according to which a cell is chosen for trangmiggiQn of a m~gs~ge. The highest priority level is when there is current location information for an MSU which has left its CPA, in which case a registration signal was transmitted by the MSU and stored with the system controller to identify that cell outside the CPA. The next highest priority level is when no registration information is found in the ~y~ controller and the CPA data is used. The first cell chosen in the CPA is either the one with the highest usage index, or alternatively is the one where the MSU most recently received a messAge or the cell where the MSU just re-entered its CPA. Thereafter, cells with lower priorities in the CPA are used until exhausted and no reply to the location confirming signal is made.
The procedure for updating the usage index and CPA data in the ~iy~ l controller is shown in FIG. 11. In step 872, if the mPcs~ge trancmitte-l in step 840 is acknowledged in step 850 or a registration signal is received for an MSU, the UI for the cell in which the mPgs~ge was tra~mitte~l and acknowledged, or the registration signal received, is incremented. Thus, the usage index represents a number of m~ss~ge receiving events by a me~gg~ge subscriber unit ~n each cell. In addition, a occurrence counter is incremented. Next, in step 874, it is determined whether the UI for that cell is greater than a first predetermined threshold Thl under the condition that at the last iteration or update the UI for that cell was less than or equal to the first predetermined threshold Thl.
When it is determined in step 874 that the UI for a cell exceeds the first predetf~rmin~ threshold Thl when at the last update it was not, then cell is marked with an addition mark M2. The addition mark M2 indicates that the system controller is planning to add the cell to the CPA for that MSU, but will wait until the MSU has ~ onfirme~ reception of a CPA
update mf~cs~ge which instructs the MSU to add that cell to its CPA. Thus, the CPA data in the ~y:.lelll controller and the MSU will match because the system controller updates its CPA data for the MSU only when it receives acknowle~gm~nt that the MSU received the CPA updated m~gs~ge.
In step 878, when the counter exceeds a predet~rminel1 maximum number of total m~gs~ge receiving events (including acknowledged CA 02226446 l998-0l-07 WO 97/035~9 PCT/US96/06686 mess~ges and registration signals) Nmax, then in step 880, the UI's are norm~li7e~l or scaled down a~ropliately and the counter is reset. In step 882, after the norm~li7~tion of step 880, the UI for each cell is compared with a second predetermined threshold Th2 to determine if it is less than 5 or equal to the second predetermined threshold Th2, when before norm~li7~tion, UI for the cell was greater than the second predetermined threshold Th2. If the UI for the cell is less than the threshold Th2 when before normalization the UI was greater than the threshold Th2, the cell is marked with a deletion mark M1. The deletion mark M1 indicates that 10 the system controller is planning to delete the cell from the CPA for that MSU, but that the MSU has not yet confirm~l reception of a CPA update message which instructs the MSU to delete the cell from its CPA.
Referring back to FIG. 8, the system controller removes the mark M1 or M2 associated with a cell when the system controller receives an 15 ACK signal, indicating that the MSU receives the requested mP~ss~ge and the CPA update mes~ge. The cell is then either added or deleted from the CPA accordingly in the system controller 300.
Thus, the CPA update procedure of FIG. 11 has a hy~lere~is characteristic in that a cell, once added to the CPA,is not imme~ tely 20 deleted from the CPA once its UI drops significantly. Rather, it is a very adaptive and gradual process. The value of Nmax is chosen to not be too big so as to be too slow in responding to changes. Its value is optionally different for light users versus heavy users in the system. The first predetermined threshold Thl and the second predetermined threshold 25 Th2 are chosen to provide a stable tracking of the CPA data without substantial oscillation.
FIG. 12 illustrates how the system controller processes reception of a registration signal from an MSU. In step 900, the system controller receives the registration signal relayed to it by the cell-located receiver that30 received it. In step 902, the CPA and UI are updated by the same procedure shown in FIG. 11 when a registration signal is received. In addition, in step 902, the ~y~L~ controller 300 stores a current location of the MSU
based on in which cell the MSU most recently received a message and acknowledged reception of the message. This is useful in determining 35 which cell in the CPAis first chosen for tran~mi~sion of a location confirming signal for the next m~s~ge request, explained above in conjunction with step 814 in FIG. 10.
CA 02226446 l998-0l-07 Referring to FIGS. 9 and 13, the procedures by which an MSU
processes CPA updating information and other sign~l~ is described. In FIG. 9, the MSU receives a mesS~ge in step 1000. The m~s~ge referred to in step 1000 is a data mess~e, voice m-~s~ge, or graphics m~s~ge, etc., which is created by a party via the input devices 410-440, for example, shown in FIG. 1. In step 1002, the MSU determines whether the quality of the received m~sAge is sati~f~c~tory and reliable. When the meSsAge received is not of s~tisf~ctory or reliable quality, then a NACK response signal is tran~mitte~l by the MSU in step 1010. This may be followed up by 10 a repeat tran~mi~ion of the m~s~ge to the MSU by the ~y~Lel~- controller 300.
When the quality of the received mP~s~e is s~lffi~ nt, then in step 1004, it is rle~rmined whether a CPA update m~ss~e is attached to the m~csAge. When a CPA update ml~s~ge exists with the received mPss~ge, 15 the CPA data stored in the MSU is updated in step 1006 accordingly. For example, the CPA update m~s~ge informs the MSU to add a particular cell, such as cell C5, to the ~rer~lled cell list. When no CPA updating m~s~ge accompanies the m~oss~ge~ step 1006 is bypassed and an ACK
signal is tran~mitte-i by the MSU in step 1008.
In FIG. 13, step 1020 the MSU is periodically ~1et~rmines its location in the MSCA by comparing a received cell identifier signal with its stored CPA. When a predetPrmine~ period of time expires in step 1022, the MSU
determines in step 1024 whether it was in a cell that is within its CPA at the previous ~iet~ormination~ If it was within its CPA at the previous 25 activation period, then in step 1026, the MSU det~rmin~ whether it is cull~lllly within its CPA. If the MSU ~et~ormines that it is still in its CPA
in step 1026, then there is no need to transmit a registration signal and the MSU can return to its normal listening mode during which it detects its address in a tr~n~mitte.l signal in a cell.
When the MSU determines in step 1024 that it was outside its CPA
at the previous determination or was inside its CPA at the previous determination, but at the present ~ielP...,i.l~tion is no longer inside the CPA (step 1026), then in step 1028, it determines whether the cell idf-ntifiPr signal transmitted in the cell corresponds to a new cell (different from the 35 cell outside the CPA at the previous determination) which is also outside its CPA or whether it is in a cell which is inside its CPA. In step 1028, when the cell i~ntifier signal received by the MSU corresponds to a cell outside the CPA different from the non-CPA at the previous CA 02226446 l998-0l-07 determination, then the MSU transmits a location registration signal in step 1030. On the other hand, when the MSU has not moved to a different - non-CPA cell, then a location registration signal is not transmitted because there is no new location information to report. Furthermore, when the 5 cell identifier signal received by the MSU corresponds to a cell inside the CPA, then this indicates that the MSU has moved back into its CPA and in step 1030 the MSU transmits a location registration signal. Thus, whenever the MSU moves out of its CPA it transmits a registration signal, and whenever the MSU moves to a different cell outside its CPA, it 10 transmits a registration signal.
The location registration signal transmitted in step 1030 is, for example, a signal which i-1~ntifie~s the MSU which transmits it and also identifies (by address) the cell from which it is transmitted. Thus, the system controller 300, by receiving a registration signal, knows which 15 MSU transmitte~l it, and from which cell the signal was transmitted.
The procedures of FIGS. 9 and 13 are implemented, for example, by firmware stored in the ROM 702 or software stored in the RAM 704 of the MSU.
A particular advantage of the present invention is that the majority 20 of the "intelligence" for locating an MSU and tracking the mobility pattern of the MSU in the MSCA, is in the system controller. The MSU merely stores the ~rt ~lled cell list, which is updated by the system controller with the next tra~smission of a m~ss~ge to the MSU. Furthermore, updating of the CPA data in the MSU is achieved with minimal additional "air time"
25 because the CPA update me~ss~ge is transmitted with the next mess~ge to be sent to the MSU.
The above description is intended by way of example only and is not intended to limit the present il~v~l~lion in any way except as set forth in the following rl~ims What is ~ ime-1 is:
Claims (10)
1. A method for managing communication of messages to message subscriber units in a two-way messaging system comprising steps of:
providing a plurality of message subscriber units which are subscribed to receive messages in a messaging system coverage area, each of said message subscriber units receiving a message and transmitting a response signal upon reception of a message;
storing in a system controller, customer paging area data for each message subscriber unit, said subscriber unit comprising a preferred cell list of cell identifiers which define a customer paging area for each message subscriber unit that comp[rises predetermined ones of a plurality of cells in a messaging system coverage area where a message subscriber unit is most receiving messages;
receiving at the system controller a message request including a message for transmission to a particular message subscriber unit;
determining in which cell the particular message subscriber unit is located based on customer paging area data for the particular message subscriber unit stored in the system controller;
transmitting the message for the particular message subscriber unit in a particular cell based on said step of determining;
transmitting a response signal from the particular message subscriber unit when the particular message subscriber unit receives the messages; and updating the customer paging area data for each message subscriber unit by adding and deleting cells from the customer paging area for each message subscriber unit according to a mobility pattern of each message subscriber unit in the messaging system coverage area, the step of updating comprises steps of:
generating a usage index associated with each cell for each message subscriber unit, the usage index representing a number of message receiving events by a message subscriber unit in a cell;
increasing the usage index for each cell for each message subscriber unit in response to an occurrence of a message receiving event in a cell by each message subscriber unit;
comparing the usage index with a first predetermined threshold after the step of increasing; and marking a cell with an addition mark which is to be added to the preferred cell list when its usage index before the step of increasing was less that the first predetermined threshold.
providing a plurality of message subscriber units which are subscribed to receive messages in a messaging system coverage area, each of said message subscriber units receiving a message and transmitting a response signal upon reception of a message;
storing in a system controller, customer paging area data for each message subscriber unit, said subscriber unit comprising a preferred cell list of cell identifiers which define a customer paging area for each message subscriber unit that comp[rises predetermined ones of a plurality of cells in a messaging system coverage area where a message subscriber unit is most receiving messages;
receiving at the system controller a message request including a message for transmission to a particular message subscriber unit;
determining in which cell the particular message subscriber unit is located based on customer paging area data for the particular message subscriber unit stored in the system controller;
transmitting the message for the particular message subscriber unit in a particular cell based on said step of determining;
transmitting a response signal from the particular message subscriber unit when the particular message subscriber unit receives the messages; and updating the customer paging area data for each message subscriber unit by adding and deleting cells from the customer paging area for each message subscriber unit according to a mobility pattern of each message subscriber unit in the messaging system coverage area, the step of updating comprises steps of:
generating a usage index associated with each cell for each message subscriber unit, the usage index representing a number of message receiving events by a message subscriber unit in a cell;
increasing the usage index for each cell for each message subscriber unit in response to an occurrence of a message receiving event in a cell by each message subscriber unit;
comparing the usage index with a first predetermined threshold after the step of increasing; and marking a cell with an addition mark which is to be added to the preferred cell list when its usage index before the step of increasing was less that the first predetermined threshold.
2. The method of claim 1, and further comprising steps of:
scaling down the usage index for each cell when a total number of message receiving events for the particular message subscriber unit exceeds a predetermined maximum;
comparing the usage index for the particular message subscriber unit for each cell with a second predetermined threshold after scaling down; and marking a cell for deletion from the preferred cell list with a deletion mark when a cell has a usage index less than the second predetermined threshold and which prior to scaling down had a usage index greater than the second predetermined threshold.
scaling down the usage index for each cell when a total number of message receiving events for the particular message subscriber unit exceeds a predetermined maximum;
comparing the usage index for the particular message subscriber unit for each cell with a second predetermined threshold after scaling down; and marking a cell for deletion from the preferred cell list with a deletion mark when a cell has a usage index less than the second predetermined threshold and which prior to scaling down had a usage index greater than the second predetermined threshold.
3. The method of claim 1, and further comprising the step of storing in each message subscriber unit the customer paging area data associated with each message subscriber unit.
4. The method of claim 3, wherein said preferred cell list being arranged in descending order of priority, and further comprising the step of periodically transmitting in each cell a cell identifier signal which includes a cell identifier.
5. The method of claim 4, and further comprising the steps of:
transmitting a registration signal from the particular message subscriber unit when the particular message subscriber unit leaves its customer paging area as determined in response to receiving a cell identifier signal having a cell identifier corresponding to a cell which is not in the customer paging area when a previously received cell identifier signal had a cell identifier corresponding to a cell inside the customer paging area of the particular message subscriber unit, or when the particular message subscriber unit is outside its customer paging area and determines that it is in a new cell in response to receiving a cell identifier signal having a cell identifier different from a cell identifier in a previously received cell identifier signal; and receiving the registration signal in the cell outside the customer paging area of the particular message subscriber unit and relaying the registration signal to the system controller for registering and storing a location for the particular message subscriber unit.
transmitting a registration signal from the particular message subscriber unit when the particular message subscriber unit leaves its customer paging area as determined in response to receiving a cell identifier signal having a cell identifier corresponding to a cell which is not in the customer paging area when a previously received cell identifier signal had a cell identifier corresponding to a cell inside the customer paging area of the particular message subscriber unit, or when the particular message subscriber unit is outside its customer paging area and determines that it is in a new cell in response to receiving a cell identifier signal having a cell identifier different from a cell identifier in a previously received cell identifier signal; and receiving the registration signal in the cell outside the customer paging area of the particular message subscriber unit and relaying the registration signal to the system controller for registering and storing a location for the particular message subscriber unit.
6. A two-way messaging system comprising:
a plurality of message subscriber units each comprising a receiver for receiving signals, a transmitter for transmitting response signals in response to receiving signals, and a memory for storing customer paging area data comprising cell identifiers corresponding to predetermined ones of cells in a messaging system coverage area where a message subscriber unit is most receiving messages;
a plurality of cells collectively defining a messaging system coverage area;
a plurality of base stations each associated with a cell and comprising a transmitter for transmitting signals to message subscriber units in a cell;
a plurality of receivers, at least one receiver being associated with a cell and coupled to a base station for receiving response signals from message subscriber units in a cell; and a system controller coupled to each base station and comprising a memory for storing the customer paging area data for each message subscriber unit, the system controller receiving a message request including a message for transmission to a particular message subscriber unit and coupling the message for transmission by a base station in a particular cell to the particular message subscriber unit based on the customer paging area data for the particular message subscriber unit stored in the system controller, the system controller automatically updating the customer paging area data for each message subscriber unit by tracking a mobility pattern of each message subscriber unit in the messaging system coverage area and by generating a usage index associated with each cell for each message subscriber unit, the usage index indicating a number of message receiving events by a message subscriber unit in a cell; increasing the usage index for each cell for each message subscriber unit in response to an occurrence of a message receiving event in a cell by each message subscriber unit; comparing the usage index with a first predetermined threshold which before the step of increasing was less than the first predetermined threshold.
a plurality of message subscriber units each comprising a receiver for receiving signals, a transmitter for transmitting response signals in response to receiving signals, and a memory for storing customer paging area data comprising cell identifiers corresponding to predetermined ones of cells in a messaging system coverage area where a message subscriber unit is most receiving messages;
a plurality of cells collectively defining a messaging system coverage area;
a plurality of base stations each associated with a cell and comprising a transmitter for transmitting signals to message subscriber units in a cell;
a plurality of receivers, at least one receiver being associated with a cell and coupled to a base station for receiving response signals from message subscriber units in a cell; and a system controller coupled to each base station and comprising a memory for storing the customer paging area data for each message subscriber unit, the system controller receiving a message request including a message for transmission to a particular message subscriber unit and coupling the message for transmission by a base station in a particular cell to the particular message subscriber unit based on the customer paging area data for the particular message subscriber unit stored in the system controller, the system controller automatically updating the customer paging area data for each message subscriber unit by tracking a mobility pattern of each message subscriber unit in the messaging system coverage area and by generating a usage index associated with each cell for each message subscriber unit, the usage index indicating a number of message receiving events by a message subscriber unit in a cell; increasing the usage index for each cell for each message subscriber unit in response to an occurrence of a message receiving event in a cell by each message subscriber unit; comparing the usage index with a first predetermined threshold which before the step of increasing was less than the first predetermined threshold.
7. The system of claim 6, wherein the system controller;
scales down the usage index for each cell when a total number of message receiving evens for the particular message subscriber unit exceeds a predetermined maximum;
compares the usage index for the particular message subscriber unit for each cell with a second predetermined threshold after scaling down;
and marks a cell for deletion from the customer paging area with a deletion mark when its usage index is less than the second predetermined threshold and which prior to scaling down was greater than the second predetermined threshold.
scales down the usage index for each cell when a total number of message receiving evens for the particular message subscriber unit exceeds a predetermined maximum;
compares the usage index for the particular message subscriber unit for each cell with a second predetermined threshold after scaling down;
and marks a cell for deletion from the customer paging area with a deletion mark when its usage index is less than the second predetermined threshold and which prior to scaling down was greater than the second predetermined threshold.
8. The system of claim 6, wherein the transmitter of each base station periodically transmits a cell identifier signal in an associated cell, the cell identifier signal including a cell identifier for the associated cell.
9. The system of claim 8, wherein the particular messaging subscriber unit receives the cell identifier signal and compares the cell identifier with its customer paging area data stored therein, and when the particular message subscriber unit leaves its customer paging area as determined in response to receiving a cell identifier signal having a cell identifier corresponding to a cell which is not in its customer paging area when a previously received cell identifier signal had a cell identifier corresponding to a cell inside the customer paging area of the particular message subscriber unit, or when the particular message subscriber unit is outside its customer paging area and determines that it is in a new cell in response to receiving a cell identifier signal having a cell identifier different from a cell identifier in a previously received cell identifier signal;
wherein a receiver in the cell where the particular message subscriber unit transmits the registration signal receives the registration signal and relays it to the system controller; and the system controller registers and stores a location for the particular message subscriber unit in response to the registration signal.
wherein a receiver in the cell where the particular message subscriber unit transmits the registration signal receives the registration signal and relays it to the system controller; and the system controller registers and stores a location for the particular message subscriber unit in response to the registration signal.
10. The systems of claim 9, wherein the system controller determines a location of the particular message subscriber unit based on a cell in its customer paging area where the particular message subscriber unit most recently received a message, and the system controller assigns a priority to the cell, where the particular message subscriber unit most recently received a message.
Applications Claiming Priority (3)
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|---|---|---|---|
| US08/500,280 US5649289A (en) | 1995-07-10 | 1995-07-10 | Flexible mobility management in a two-way messaging system and method therefor |
| US08/500,280 | 1995-07-10 | ||
| PCT/US1996/006686 WO1997003529A1 (en) | 1995-07-10 | 1996-05-13 | Flexible mobility management in a two-way messaging system and method therefor |
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| CA2226446A1 CA2226446A1 (en) | 1997-01-30 |
| CA2226446C true CA2226446C (en) | 2000-10-17 |
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| CA002226446A Expired - Fee Related CA2226446C (en) | 1995-07-10 | 1996-05-13 | Flexible mobility management in a two-way messaging system and method therefor |
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| EP (1) | EP0882369B1 (en) |
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-
1995
- 1995-07-10 US US08/500,280 patent/US5649289A/en not_active Expired - Lifetime
-
1996
- 1996-05-13 JP JP50578897A patent/JP2001520816A/en not_active Ceased
- 1996-05-13 EP EP96914610A patent/EP0882369B1/en not_active Expired - Lifetime
- 1996-05-13 DE DE69624266T patent/DE69624266T2/en not_active Expired - Fee Related
- 1996-05-13 AU AU57915/96A patent/AU5791596A/en not_active Abandoned
- 1996-05-13 CA CA002226446A patent/CA2226446C/en not_active Expired - Fee Related
- 1996-05-13 CN CN96195428A patent/CN1108065C/en not_active Expired - Fee Related
- 1996-05-13 TW TW085105628A patent/TW317683B/zh not_active IP Right Cessation
- 1996-05-13 KR KR1019980700141A patent/KR100261829B1/en not_active IP Right Cessation
- 1996-05-13 WO PCT/US1996/006686 patent/WO1997003529A1/en active IP Right Grant
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1998
- 1998-01-09 MX MX9800294A patent/MX9800294A/en not_active IP Right Cessation
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| WO1997003529A1 (en) | 1997-01-30 |
| DE69624266D1 (en) | 2002-11-14 |
| EP0882369A1 (en) | 1998-12-09 |
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| AU5791596A (en) | 1997-02-10 |
| JP2001520816A (en) | 2001-10-30 |
| EP0882369A4 (en) | 2000-06-07 |
| CN1108065C (en) | 2003-05-07 |
| DE69624266T2 (en) | 2003-03-06 |
| CA2226446A1 (en) | 1997-01-30 |
| US5649289A (en) | 1997-07-15 |
| KR100261829B1 (en) | 2000-07-15 |
| CN1190519A (en) | 1998-08-12 |
| KR19990028840A (en) | 1999-04-15 |
| TW317683B (en) | 1997-10-11 |
| EP0882369B1 (en) | 2002-10-09 |
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