CN1110914C - Adaptive random access agreement and dynamic searching tree expanding resolving for multi-station net - Google Patents

Abstract

A CATV communication system has stations which communicate data in a data frame having a plurality of slots, wherein the plurality of slots are new message minislots NMS, expansion minislots EMS, and data slots DS. A master station determines a range parameter R which is based upon a number of slave stations transmitting reservation requests in a data frame. The master station also determines a parameter MAP according to a number of reservation requests in a queue waiting to be processed by the master station. The parameter MAP defines the new message minislots, the expansion minislots, and the data slots in an upstream data frame. The master station transmits the range parameter R and the parameter MAP to a plurality of slave stations. Each slave station independently determines a random transmission parameter RN. Each slave station transmits to the master station (i) a new reservation request in a new message minislot if its random transmission parameter RN corresponds to the parameter MAP, (ii) an old reservation request in an expansion minislot if assigned an expansion minislot in the parameter MAP, and (iii) data in a data slot if assigned a data slot by the master station.

Description

The adaptive random access agreement and the dynamic search tree expansion that are used for the multistation net are decomposed

The sequence number of submitting in the present invention and on October 22nd, 1996 is that 08/734,909 U.S. Patent application and the sequence number submitted on October 22nd, 1996 are that invention disclosed is relevant in 08/734,908 the U.S. Patent application.

Technical field

The present invention relates to be used for the wherein agreement and the dynamic search tree expansion process of the communication system of the shared common user communication channel inlet of multistation.

Background technology

Communication system generally comprises a plurality of interconnective stations of common user communication channel of passing through.For example, in a community antenna television (CATV) (CATV) system, an initiating terminal is connected with a plurality of subscriber stations by a cable.This cable is supported downlink communication and the uplink communication from subscriber station to initiating terminal from initiating terminal to subscriber station.The data of transmitting between initiating terminal and subscriber station send in Frame.Therefore, when initiating terminal and a subscriber station communications, initiating terminal sends downlink data frame to subscriber station, and when a subscriber station was communicated by letter with initiating terminal, subscriber station sent uplink data frames to initiating terminal.

In this CATV system, initiating terminal and subscriber station must be shared the resource of cable in some way.For example, generally be assigned to different frequency ranges with uplink communication descending.Cut apart in the distribution low, downlink communication is assigned between 54MHz and the 750MHz and higher frequency range, and uplink communication is assigned to the following frequency range of 42MHz.In cut apart in the distribution, downlink communication is assigned to 162MHz and above frequency range, and uplink communication is assigned to the frequency range between 5 to 100MHz.Cut apart in the distribution at height, downlink communication is assigned to 234MHz and above frequency range, and uplink communication is assigned to the frequency range between 5MHz and the 174MHz.

In addition, each subscriber station also must be shared the resource of cable in some way.In time division multiple access (TDMA) CATV system, each subscriber station is generally shared cable by send data in unique distribution and time cycle non-overlapping copies.In frequency division multiple access (FDMA) CATV system, by available upstream band width being divided into a plurality of narrow channels and, making each subscriber station share cable for each subscriber station distributes the narrow-band of himself unique correspondence.In code division multiple access (CDMA) CATV system, each subscriber station is shared cable by the mode that the distribution codeword that their data-message be multiply by correspondence sends its result then.

Each subscriber station is distributed to the tdma system of a unique time slot and avoided the collision of the data of each subscriber station transmission, but limited the data throughput from the subscriber station to the initiating terminal.Therefore because it is limited distributing to the number of frequency bands of subscriber station, the FDMA system for the narrow-band of himself unique correspondence of each subscriber station distribution has limited data throughput equally.Equally, be limited owing to can distribute to the quantity of the code word of subscriber station, cdma system has limited the data throughput of telecommunication cable.

In order to improve the throughput of the data that subscriber station sends to the initiating terminal of CATV system, known can be supporting be divided into a plurality of small time slots and data slot to the uplink data frames of initiating terminal communication from subscriber station.There are data need in a small time slot of current uplink data frames (that is, discrete time n uplink data frames), insert a reservation request to those subscriber stations that initiating terminal sends.This reservation request requires initiating terminal to reserve data slot for those subscriber stations uses in a follow-up uplink data frames (for example, discrete time n+1 uplink data frames).

Because the small time slot quantity in the uplink data frames of being used by this current system is limited, so between the subscriber station contention of the small time slot of access limited quantity has been caused frequent impact (that is contention) between the reservation request.But, wish that at least some reservation request will successfully send to initiating terminal by subscriber station, and can in any given uplink data frames, not bump.Therefore, it is generally acknowledged that final all subscriber stations all can be to their data of initiating terminal transmission in the data slot of reserving for this purpose.Also be because the quantity of the small time slot in this system is limited and fixing, thereby the throughput in this system is subjected to corresponding restriction.

Also known by the method that allows frequency, time or code word time slot identical in the subscriber station contention uplink data frames and use a kind of tree algorithm to eliminate the collision of any generation and improved the data throughput that subscriber station sends to initiating terminal.When sending data in the identical time slot of a uplink data frames or identical a plurality of time slots, two or more subscriber stations produce collision.When initiating terminal detected this collision, initiating terminal began a tree algorithm, and this tree algorithm is wherein to exist each contention slots in the uplink data frames in advance of collision to distribute the expansion time slot of predetermined quantity in next uplink data frames for second layer contention.That is to say that tree algorithm expands to each contention slots that wherein has collision the expansion time slot of predetermined quantity.

This expansion that the response initiating terminal carries out, each subscriber station determine whether it wherein exists the time slot of collision to send at one.Each has determined that it exists the subscriber station that has carried out sending in the contention slots of collision to select one to send the expansion time slot of the contention slots of uplink data frames in advance of data therein corresponding to it randomly at one in next uplink data frames.Then, these subscriber stations send their data once more in the expansion time slot of selecting at random of correspondence.If initiating terminal detects collision once more, tree algorithm is wherein to exist each time slot in the uplink data frames in advance of colliding to distribute predetermined quantity expansion time slot in next Frame for the 3rd layer of contention so.Subscriber station in the contention responds as before.By this way, solved contention.

Summary of the invention

The present invention relates to system that a kind of feature of agreement of the quantity that dynamically changes a small time slot in the uplink data frames when needed and a kind of feature that is used for solving the dynamic tree algorithm of contention when in the collision of the two or more stations of the same time slot of a uplink data frames are combined.IEEE (Institute of Electrical and Electronics Engineers (U.S.)) is working out the standard (802.14) relevant for a kind of like this system.

According to an aspect of the present invention, a station is provided, comprise: the receiving system that is used to receive downlink data frame with a range parameter R and a parameter MAP, wherein parameter MAP has defined a plurality of new message small time slot NMS in next uplink data frames, a plurality of expansion small time slot EMS and a plurality of data slot DS by a dynamic search tree expansion process expansion; Be used to produce the transmission parameter generation device of a transmission parameter RN, wherein transmission parameter RN is subjected to the constraint of range parameter R; And emitter, be used for sending a reservation request in the new message small time slot in next uplink data frames as transmission parameter RN during corresponding to new message small time slot; Be used for when this station sent a reservation request in one is gone ahead of the rest uplink data frames and small time slot that be expanded in next uplink data frames, in an expansion small time slot of next uplink data frames, sending a reservation request once more; And during the data slot that is used for reserving, in this data slot, send data when promising this station.

Description of drawings

Can more clearly understanding be arranged to these and other advantage of the present invention by detailed description of the present invention below in conjunction with accompanying drawing, wherein:

Fig. 1 is a schematic diagram that comprises the CATV system of an initiating terminal that is connected in a plurality of subscriber stations with cable, and this system is the example of communication system constructed according to the invention;

Fig. 2 is illustrated in the downlink data frame that initiating terminal wherein sends to the subscriber station of Fig. 1;

Fig. 3 is illustrated in the uplink data frames that subscriber station wherein sends to the initiating terminal of Fig. 1;

Fig. 4 A illustrates the example according to the small time slot among a kind of uplink data frames F1-F7 of dynamic expansion trie tree expansion algorithm;

Fig. 4 B illustrates the example according to the small time slot among a kind of uplink data frames F1-F7 of fixedly expansion trie tree expansion algorithm;

Fig. 5 illustrates a kind of time slot format of uplink data frames;

Fig. 6 A and 6B have shown the program that the initiating terminal by Fig. 1 is in one embodiment of the invention carried out;

Fig. 7-the 10th, the curve chart that in the program of key-drawing 6A and 6B, uses;

Figure 11 A and 11B have shown the program of each subscriber station execution of Fig. 1 in an embodiment of the present invention.

Embodiment

Fig. 1 illustrates one and comprises an initiating terminal 12, a plurality of subscriber stations 14 ₁-14 _nWith one be connected initiating terminal 12 and subscriber station 14 ₁-14 _nBetween the CATV system 10 of cable 16.According to the present invention, initiating terminal 12 can be to be equipped with one can programme with the usual hardware design of supporting the processor by cable 16 downlink communications.Equally, according to the present invention, subscriber station 14 ₁-14 _nCan be that each is equipped with one and can programmes to support the usual hardware design by the processor of cable 16 uplink communications.

According to the present invention, when subscriber station 14 ₁-14 _nHave data to pass through cable 16 when initiating terminal 12 transmits, these subscriber stations at first carry out reservation request.In carrying out reservation request, because small time slot is from subscriber station 14 ₁-14 _nCarry reservation request to initiating terminal 12, subscriber station 14 ₁-14 _nTo the still mutual contention of small time slot of dynamically changeable quantity limited in the uplink data frames.For those reservation request that successfully received by initiating terminal 12 (that is, being received by initiating terminal 12 in the small time slot that does not have collision), initiating terminal 12 passes through from the subscriber station 14 of initiating terminal 12 to success ₁-14 _nThis reservation request is confirmed in an affirmation that sends.Therefore, uplink data frames is divided into a plurality of time slot S, among these time slots S some or most ofly be divided into a plurality of small time slot MS again, make all contentions and reservation activity occur in the small time slot of uplink data frames, and all transfer of data occur among the data slot DS that does not divide again of time slot S.

Initiating terminal 12 prescribed hour crack MS and the arrangement of data slot DS in downlink data frame.Subscriber station 14 ₁-14 _nUtilize this predetermined arrangement and some other parameter so that make the decision whether they can send reservation request and data in a follow-up uplink data frames.Therefore, subscriber station 14 ₁-14 _nThe bandwidth of contention up channel.The reservation request of a success causes initiating terminal 12 to reserve one or more data slots according to availability for the subscriber station that each has sent successful reservation request.The quantity of the operable reserved data time slot of any one subscriber station depends on the quantity of the subscriber station that has carried out successful reservation request.

The size of uplink and downlink Frame can equate, can fix, and can be defined as, for example have equal at least initiating terminal processing time and cable 16 round trip propagation delay times and size.

An exemplary downlink data frame has been shown among Fig. 2.Each such downlink data frame has four parts.First comprises a range parameter R.When the subscriber station in the contention has the non-reservation request that in advance sends and will send, subscriber station 14 ₁-14 _nCan utilize the new message small time slot of range parameter R contention.

The second portion of downlink data frame comprises a minislot parameter MAP.Which time slot that minislot parameter MAP defines next uplink data frames is (i) subscriber station 14 ₁-14 _nBe used to send the new message small time slot (NMS) of new reservation request (that is, also the reservation request that was not in advance sent), (ii) subscriber station 14 ₁-14 _nBe used to send sent in advance and with the reservation request of colliding expansion small time slot (EMS) with (iii) keep for subscriber station 14 from the reservation request of other subscriber station ₁-14 _n, make subscriber station 14 ₁-14 _nCan send the data slot (DS) of data.For example, minislot parameter MAP can be each the new message small time slot in the next uplink data frames of definition, the map of the position of each expansion small time slot and each data slot.Map can make these new message small time slots, and expansion small time slot and data slot are dispersed in the whole uplink data frames.Subscriber station 14 ₁-14 _nRead map, so that determine which time slot in the uplink data frames is new message small time slot, which time slot in the uplink data frames is which time slot in expansion small time slot and the uplink data frames is a data slot.

As selection, minislot parameter MAP divides time slot in the uplink data frames, the border between new message small time slot, expansion small time slot and the data slot.In this case, new message small time slot, expansion small time slot and data slot are isolated mutually.

In addition, can give the small time slot assignment RQ# (that is RQ number) that is included in the next uplink data frames.Therefore, can for be included in the next uplink data frames and subscriber station 14 ₁-14 _nBe used for sending the new message small time slot assignment RQ#=0 of new reservation request (that is the reservation request that was not also in advance sent).Thereby one has subscriber station that a reservation request that was not in advance sent will send and can send the reservation request that was not in advance sent in a small time slot that is endowed 0 RQ number.

Can not be that 0 RQ number is given (i) subscriber station 14 one ₁-14 _nBe used for being sent in once more a uplink data frames of going ahead of the rest and reservation request from other subscriber station took place collision reservation request the expansion small time slot and (ii) expand the corresponding contention small time slot of uplink data frames in advance of small time slot.For example, the small time slot 16 of uplink data frames n if go ahead of the rest, 27, collision has taken place in 33 and 45, initiating terminal 12 is pointed out small time slot 16 in advance corresponding to one 4 RQ number in minislot parameter MAP, and initiating terminal 12 will for 4 RQ number give in next uplink data frames n+1 and in advance small time slot 16 be extended to the expansion small time slot.Equally, (i) initiating terminal 12 points out that in minislot parameter MAP small time slot 27 in advance is corresponding to one 3 RQ number, and initiating terminal 12 will for 3 RQ number give in next uplink data frames n+1 and in advance small time slot 27 be extended to the expansion small time slot, (ii) initiating terminal 12 points out that in minislot parameter MAP small time slot 33 is corresponding to the RQ number that is 2 in advance, and initiating terminal 12 with one 2 RQ number give in next uplink data frames n+1 and in advance small time slot 33 be extended to the expansion small time slot, (iii) initiating terminal 12 is pointed out small time slot 45 in advance corresponding to one 1 RQ number in minislot parameter MAP, and initiating terminal 12 will for 1 RQ number give in next uplink data frames n+1 and in advance small time slot 45 be extended to the expansion small time slot.

Therefore, if a subscriber station has sent a reservation request in the small time slot 16 of uplink data frames n of going ahead of the rest, this subscriber station detects the RQ number that the small time slot 16 of uplink data frames n in advance is endowed 4, and will be endowed in 4 RQ number and the expansion small time slot in next uplink data frames n+1 at one and send this reservation request once more.Should be noted that maximum RQ number is to be determined by the quantity of the small time slot that experiences collision.In above-mentioned example, four small time slots (that is, small time slot 16,27,33 and 45) have experienced collision, and therefore maximum RQ number is 4.

The third part of downlink data frame is exclusively used in subscriber station 14 ₁-14 _nConfirm to the reservation request of initiating terminal 12 success transmissions in the uplink data frames at one in advance.Each confirms that field (ACK) can comprise, for example, (i) station ID, it be given affirmation subscriber station the address and (ii) keep for by subscriber station and the subscriber station this sign of station ID sign can be therein to one or more data slots of initiating terminal 12 transmission data.

The 4th part of downlink data frame comprises initiating terminal 12 and can be used for to subscriber station 14 ₁-14 _nSend the data slot of other data.

The example of a uplink data frames has been shown among Fig. 3.In this up channel, subscriber station 14 ₁-14 _nUse the minislot parameter MAP of downlink data frame in advance, so that determine the demarcation of next uplink data frames.Uplink data frames comprises a plurality of time slots.As shown in Figure 3, a time slot can be divided into a plurality of new message small time slot NMS again, and a time slot can be divided into a plurality of expansion small time slot EMS again, or a time slot can not divided (or part is divided) again and is used as a data time slot DS.New message small time slot NMS, the mixing of expansion small time slot EMS and data slot DS is by initiating terminal 12 definition, and relies on loading condition and change.Therefore, the quantity of small time slot depends on the degree of collision and the quantity of the reservation request in the reservation request formation DQ of initiating terminal 12 dynamically changes.A time slot can be divided into new message small time slot NMS and/or the expansion small time slot EMS of a fixed qty m again.

When two or more reservation request from the respective user station were collided in one of a uplink data frames new message small time slot or in expansion small time slot, message small time slot that this is new or expansion small time slot were expanded in a follow-up uplink data frames and are a plurality of expansion small time slots.Fig. 4 A shows the dynamic search tree expansion process of a new message small time slot that is used to expand wherein bump and/or expansion small time slot.When not colliding in one is gone ahead of the rest uplink data frames, all small time slots in next uplink data frames all are new message small time slots, and allow subscriber station 14 ₁-14 _nIn these new message small time slots of contention any one.When bumping subsequently, system enters the ground floor contention.Therefore, the ground floor contention takes place when having collision in the new message small time slot.Uplink data frames F1 among Fig. 4 A has shown a ground floor contention.The new message small time slot that does not wherein bump is designated as NC, and the new small time slot that wherein bumps is designated as C, and a subscript letter is being followed to distinguish these new message small time slots in its back.

Therefore, spreading coefficient E of initiating terminal 12 usefulness (can be 6 for example) expands each the new message small time slot that wherein bumps between the ground floor contention-free period.This value of spreading coefficient E depends on the collision quantity in the new message small time slot of uplink data frames F1.Therefore, initiating terminal 12 expands to each the new message small time slot that wherein bumps the expansion small time slot of six correspondences of second layer contention.Second layer contention takes place when having collision in the expansion small time slot.For example, it is six expansion small time slots that new message small time slot Ca is expanded, and consequently all these six expansion small time slots do not comprise collision in second layer contention.Equally, it is six expansion small time slots that small time slot Cb is expanded, and the result is that these six (Cb1) that expand in the small time slot comprise collision in second layer contention, and these six other five of expanding small time slots do not comprise collision.

Should be noted that because the quantity of small time slot in a uplink data frames is limited, can both expand to situation in the same next uplink data frames so the small time slot of not all ground floor contention may occur.Therefore, for example, be expanded in a uplink data frames F3 rather than in uplink data frames F2, being used for six expansion small time slots of second layer contention from the small time slot Cf of uplink data frames F1.These six (Cf1) that expand in the small time slot comprise collision, and these six other five of expanding small time slots do not comprise collision.

Shall also be noted that a uplink data frames can comprise the expansion small time slot of different contention layers.For example, being expanded from the small time slot Cg of the uplink data frames F1 that represents the ground floor contention is six among uplink data frames F3 expansion small time slots, and is expanded to also being that in uplink data frames F3 three expand small time slots from the small time slot Cb1 of the uplink data frames F2 that represent the second contention layer.

As another example, Fig. 4 B shows a kind of can be used to expand new message small time slot that wherein bumps and/or the fixedly trie tree expansion process of expanding small time slot.When not colliding in one is gone ahead of the rest uplink data frames, all small time slots in the next uplink data frames all are new message small time slots, and allow subscriber station 14 ₁-14 _nIn these new message small time slots of contention any one.When bumping subsequently, system enters the ground floor contention.Uplink data frames F1 in Fig. 4 B illustrates a ground floor contention.The small time slot that wherein do not bump is designated as NC, and the small time slot that wherein bumps is designated as C, and a subscript letter is being followed to distinguish these small time slots in its back.

Therefore, spreading coefficient E of initiating terminal 12 usefulness (being 3 in the example of Fig. 4 B) expands each small time slot that wherein bumps.Produce minislot parameter MAP according to spreading coefficient E at least in part.The result of this expansion is that initiating terminal 12 expands to three expansion small time slots that are used for the correspondence of second layer contention to each small time slot that wherein bumps.For example, small time slot Ca is expanded and is three among next uplink data frames F2 expansion small time slots, small time slot Cb is expanded and is three among next uplink data frames F2 expansion small time slots, and small time slot Cc is expanded three expansion small time slots into next uplink data frames F2, or the like.Uplink data frames F2 also comprises the new message small time slot that is designated as NC in Fig. 4 B, and can comprise the data slot (not shown).

Therefore, shown in upstream data frame F2, may produce a second layer contention.For example, three of expanding in the small time slots that expanded by small time slot Ca do not comprise collision, and other two (Ca1 and Ca2) of these three expansion small time slots comprise collision.Equally, three of expanding in the small time slots that expanded by small time slot Cb do not comprise collision, and these three other two (Cb1 and Cb2) that decompose in the time slot comprise collision.

Then, initiating terminal 12 expands to each small time slot of the second layer contention that wherein bumps the expansion small time slot of three correspondences that are used for the 3rd layer of contention.For example, expansion small time slot Cb1 is expanded to being used for three expansion small time slots of the 3rd contention layer, and consequently two in these three expansion small time slots do not comprise collision, and remaining one (Cb11) comprises collision in these three expansion small time slots.

The spreading coefficient E that Fig. 4 A illustrates initiating terminal 12 settings can change between the contention layer.Therefore, if when collision quantity significantly reduces, can reduce the value of E for second layer contention in second layer contention.Fig. 4 B illustrates a kind of fixedly trie tree expansion process.

Fig. 5 shows by subscriber station and inserts data in a small time slot or the data time slot.These data comprise a source address, a control field, a pay(useful) load, and error check data.Source address is the address of the subscriber station in sending.Control field is pointed out the type (for example, reservation request or data) of the message that subscriber station sends.The pay(useful) load field under the situation of a reservation requests, comprises the quantity of the data slot of subscriber station request reservation, or under the situation of a data message, comprises the data that sent by subscriber station.Crc field comprises error check information

Determining that (i) is used for the quantity of the new message small time slot NMS of next uplink data frames, (ii) is used for the quantity of the expansion small time slot EMS of next uplink data frames, (iii) spreading coefficient E and (iv) subscriber station 14 ₁-14 _nBe used for determining whether they can send among the range parameter R of reservation request at new message small time slot, and initiating terminal 12 is carried out one in the program 100 shown in Fig. 6 A and the 6B.

Each initiating terminal 12 receives a uplink data frames and just enters program 100.When the program 100 of entering, square frame 102 receives a uplink data frames, and square frame 104 is stored in any reservation request in this Frame among the reservation request formation DQ of current time n.Square frame 104 is also stored the quantity of empty new information small time slot, the quantity of empty expansion small time slot, the quantity of colliding new message small time slot (promptly, the new message small time slot of reservation request collision wherein), the quantity of collision expansion small time slot (promptly wherein reserving the expansion small time slot of collision), the quantity of the new message small time slot of success (promptly, the new message small time slot that comprises an independent reservation request), and/or the quantity of successful expansion small time slot (that is the expansion small time slot that, comprises an independent reservation request).

After this, square frame 106 determines whether CATV system 10 is in stable state.When CATV system 10 is in stable state, the quantity D S (n) of the data slot in the Frame that the quantity D Q (n) that is stored in the reservation request among the reservation request formation DQ of current discrete time n has just received greater than square frame 102, but less than this quantity of data slot DS (n) multiplication by constants α.For example, constant alpha can be 1.6.The uplink data frames that has just received is designated as uplink data frames n here, and receives at discrete time n.If system is in stable state, square frame 108 determines to distribute to the quantity of the small time slot MS of next uplink data frames n+1 according to following equation: $\mathrm{MS}(n+1)=M=\frac{S}{\frac{k}{e}+\frac{1}{m}}---\left(1\right)$

Wherein S is the sum of the time slot in a Frame, m is the quantity of the time slot small time slot that can be divided into again, e is 2.718281828..., MS (n+1) is used for the quantity of the small time slot of next uplink data frames, k is that M is the stable state number of small time slot by the average of the data slot of reservation request reservation.Because a whole time slot is used as a data time slot, therefore the quantity of the data slot in next uplink data frames n+1 is provided by following equation: $\mathrm{DS}(n+1)=S-\frac{\mathrm{MS}(n+1)}{m}.$

If square frame 106 determines that CATV systems 10 are not in stable state, whether the quantity D Q (n) that square frame 110 is determined the reservation request in the reservation request formation DQ of discrete time n initiating terminal 12 is less than the quantity D S (n) of the data slot in the uplink data frames that has just received.If like this, square frame 112 determines to distribute to the quantity of the small time slot MS of next uplink data frames n+1 according to following equation:

MS(n+1)＝m(S-DQ(n)) (2)

Wherein DQ (n) is the quantity D Q (n) of the reservation request in the reservation request formation DQ of time n initiating terminal 12.Thereby the quantity D S of the data slot in next uplink data frames n+1 (n+1) is set to DQ (n).

If square frame 106 determines that CATV system 10 is not in stable state, if and square frame 110 determines that the quantity D Q (n) of the reservation request in the reservation request formation DQ of discrete time n initiating terminal 12 is not less than the quantity D S (n) of the data slot in the uplink data frames that has just received, square frame 114 determines to distribute to the quantity MS of the small time slot of next uplink data frames n+1 according to following equation so: $\mathrm{MS}(n+1)=M-m\frac{\mathrm{DQ}\left(n\right)-\mathrm{\αDS}\left(n\right)}{6}---\left(3\right)$

Wherein DS (n) is the quantity of the reserved data time slot in the uplink data frames that has just received.Therefore, the quantity D S of the data slot in next uplink data frames n+1 (n+1) is provided by following formula: $\mathrm{DS}(n+1)=S-\frac{\mathrm{MS}(n+1)}{m}$

Will illustrate that as following small time slot MS (n+1) will be divided between new message small time slot and/or the expansion small time slot.

Square frame 116 is analyzed the uplink data frames that is received by square frame 102, so that comprise non-contention reservation request in definite message small time slot that wherein which non-NULL is new.These new small time slots only comprise the reservation request from a subscriber station.Square frame 116 is set a parameter S UC who equals these small time slot quantity _NSquare frame 116 is also analyzed the uplink data frames that is received by square frame 102, wherein comprises non-contention reservation request in which non-NULL expansion small time slot so that determine.These expansion small time slots only comprise the reservation request from a subscriber station.Square frame 116 is set a parameter S UC who equals these small time slot quantity _EIf desired, square frame 116 determines a parameter S UC can for ground floor contention each layer contention afterwards _E, make parameter S UC _E1Be suitable for second layer contention, parameter S UC _E2Be suitable for the 3rd layer of contention, or the like.

The uplink data frames that square frame 118 analyses receive is to comprise the contention reservation request in definite message small time slot that wherein which non-NULL is new.These new message small time slots comprise the reservation request from an above subscriber station.Square frame 118 is set a parameters C OL who equals these new message small time slot quantity _NSquare frame 118 is also analyzed the uplink data frames that receives, so that determine wherein which non-NULL expansion small time slot comprises the contention reservation request.These expansion small time slots comprise the reservation request from an above subscriber station.Square frame 118 is set a parameters C OL who equals the quantity of these expansion small time slots _EIf desired, square frame 118 can be determined a parameters C OL for each layer contention after the ground floor contention _E, make parameters C OL _E1Be suitable for second layer contention, parameters C OL _E2Be suitable for the 3rd layer of contention, or the like.

Square frame 120 is selected whether to calculate the effectively quantity N at station according to parameter S UC.If select to calculate, square frame 122 is determined the effectively quantity N at station from following equation: $\mathrm{SUC}=\mathrm{MS}\frac{N}{\mathrm{MS}-1}{\left(\frac{\mathrm{MS}-1}{\mathrm{MS}}\right)}^N---\left(4\right)$

Wherein N is the effective quantity at station, and MS is the sum of the small time slot in the uplink data frames that has just received, and SUC is the quantity of the non-NULL small time slot that does not wherein bump determined by square frame 116.Square frame 120 can be determined the effectively quantity at station for each contention layer, and making can be from parameter S UC _NDetermine the effectively quantity N at station _N, from parameter S UC _E1Determine the effectively quantity N at station _E1, from parameter S UC _E2Determine the effectively quantity N at station _E2, or the like.

As selection, square frame 122 can be determined at the equation look-up table according to the look-up table of the curve chart shown in Fig. 7 from the memory that is stored in initiating terminal 12 and determine effectively station quantity N.This curve is corresponding to equation (4).The vertical axis of this curve chart is a power shaft.The effective station quantity N of parameter from the memory that is stored in initiating terminal 12 that determines by square frame 104.The corresponding SUC of this curve chart imports along vertical axis.Trunnion axis is an output shaft, can determine the quantity N at effective station as the function of input vertical axis along trunnion axis.When using the curve chart of Fig. 7,, thereby produced uncertainty because each value along the vertical axis input has two output valves along trunnion axis.Use the impact curve shown in Fig. 8 can solve this uncertainty.Below incite somebody to action the curve of key-drawing 8 in more detail.

On the other hand, if square frame 120 is selected not calculate the effectively quantity at station according to parameter S UC, square frame 124 is determined the effectively quantity N at station from following equation so: $\mathrm{COL}=\mathrm{MS}-\mathrm{MS}\frac{N}{\mathrm{MS}-1}{\left(\frac{\mathrm{MS}-1}{N}\right)}^N-\mathrm{MS}{\left(\frac{\mathrm{MS}-1}{\mathrm{MS}}\right)}^N---\left(5\right)$

Wherein N is the effective quantity at station, and MS is the sum of the small time slot in the uplink data frames that has just received, and COL is the quantity of in the uplink data frames that has just received and the small time slot that wherein bump determined of square frame 118.Square frame 124 can be determined an effectively station quantity N for each contention layer, and making can be from parameters C OL _NDetermine effectively station quantity N _N, from parameters C OL _EDetermine effectively station quantity N _E1, from parameters C OL _E2Determine effectively station quantity N _E2, or the like.

As selection, can determine the effectively quantity N at station according to the look-up table of the curve chart shown in Fig. 8 from the memory that is stored in initiating terminal 12.This curve chart is corresponding to equation (5).The vertical axis of this curve chart is a power shaft.The parameters C OL that square frame 118 is determined imports along vertical axis.Trunnion axis is an output shaft, can determine quantity N as effective station of the function of vertical axis along trunnion axis.

Square frame 120 also can be made its decision according to the mark of user's setting or according to other standard.

Should be understood that and to arrange CATV system 10 only to determine the effectively quantity N at station from equation (4).If like this, square frame 122 must use collision parameter COL and square frame 124, so that solve above-mentioned uncertainty.As selection, can arrange CATV system 10 only to determine the effectively quantity N at station from equation (5), in this case, there is not uncertainty to need to solve.If like this, can cancel square frame 116,120 and 122.Select as another kind, can determine the effectively quantity N at station from the combination of parameter S UC and parameters C OL.

Square frame 126 uses effectively station quantity N, so as according in the memory that is stored in initiating terminal 12 and the look-up table consistent with curve shown in Fig. 9 determine spreading parameter E.The trunnion axis of this curve chart is a power shaft.Quantity N by the definite effective station of one of said method imports along trunnion axis.Vertical axis is an output shaft, determines spreading parameter E as the function of trunnion axis along vertical axis.Therefore, to ground floor contention basis effective station quantity N _NDetermine a spreading coefficient E _N, for second layer contention basis effective station quantity N _E1Determine a spreading coefficient E _E1, for the 3rd layer of contention basis effective station quantity N _E2Determine a spreading coefficient E _E2, or the like.

As selection, square frame 126 can according in the memory that is stored in initiating terminal 12 and the look-up table consistent with curve shown in Figure 10 determine spreading parameter E.The trunnion axis of this curve chart is a power shaft.The parameters C OL that is determined by square frame 118 imports along trunnion axis.Vertical axis is an output shaft, determines spreading parameter E as the function of trunnion axis along vertical axis.

Should be appreciated that square frame 116-126 is defined as the spreading coefficient of a dynamically changeable to spreading coefficient E to each layer contention, as explanation in conjunction with Fig. 4 did.

Square frame 128 is defined as EMS (n+1) to the quantity of the expansion small time slot in next uplink data frames n+1, and the quantity of the new message small time slot among the next uplink data frames n+1 is defined as NMS (n+1).Square frame 128 is determined an initial parameter EMS by new message small time slot and expansion small time slot that the spreading coefficient E according to correspondence expands among the uplink data frames n that wherein bumps _i(n+1).That is, square frame 128 utilizes spreading coefficient E _NThe expansion new small time slot among the uplink data frames n of (if any) that wherein bumps, square frame 128 utilizes spreading coefficient E _E1Ground floor expansion small time slot among (if any) uplink data frames n that expansion wherein bumps, square frame 128 utilizes spreading coefficient E _E2Second layer expansion small time slot among (if any) uplink data frames n that expansion wherein bumps, or the like.All these expansion small time slots are produced initial parameter EMS mutually _i(n+1).Then, square frame 128 deducts this initial parameter EMS from the quantity MS of the definite small time slot that will distribute to next uplink data frames n+1 of square frame 106-114 _i(n+1).If this result is less than NMS _Min(its can be set at 0,4 or any other number), square frame 128 is set EMS (n+1) and is equaled MS-NMS _MinAnd setting NMS (n+1) equals NMS _Min, wherein MS is determined by square frame 106-144.If this result is not less than NMS _Min, square frame 128 setting EMS (n+1) equal EMS so _iAnd set NMS (n+1) and equal MS-EMS (n+1), _i(n+1).By this way, a uplink data frames comprises and is no less than EMS _MinIndividual new message small time slot.

Square frame 130 is determined range parameter R according to following equation from parameters C OL: $R(n+1)=\max \left\{\min \right\{N,R\left(n\right)-\mathrm{NMS}\left(n\right)+$ $\frac{e-1}{e-2}\mathrm{COL}\left(n\right)+\frac{\mathrm{NMS}\left(n\right)}{e}\},\mathrm{NMS}(n+1)\}---\left(6\right)$

Wherein n indicates present frame, n+1 indicates next uplink data frames, R (n+1) is the range parameter of next uplink data frames n+1, and R (n) is the range parameter of the uplink data frames n that just received, effective station quantity N that the N representative is determined by certain combination of square frame 116-124 _NNMS (n+1) is the quantity of the new message small time slot among the next uplink data frames n+1 that is determined by square frame 128, NMS (n) is the quantity of the new message small time slot among the uplink data frames n that has just received, COL (n) is the parameters C OL that square frame 118 is determined according to the uplink data frames n that has just received, and e is 2.718281828....

Square frame 132 is determined minislot parameter MAP.If minislot parameter MAP is the map of new message small time slot, expansion small time slot and data slot, square frame 132 is according to any suitable rule so, constructs map according to the NMS (n+1) that is determined by square frame 128 and EMS (n+1) and the above-mentioned DS that determines in conjunction with square frame 106-114.As selection, square frame 132 can be by distributing to the first of uplink data frames n+1 the individual new message of NMS (n+1), the next part of uplink data frames n+1 is distributed to the individual expansion small time slot of EMS (n+1) and the remainder of uplink data frames n+1 is distributed to DS data time slot determine minislot parameter MAP.As mentioned above, square frame 132 also distributes RQ number and small time slot mark.Square frame 132 is minislot parameter MAP, and is inserted in the next downlink data frame that will send as the range parameter R (n+1) of parameters R.

Square frame 134 is inserted into any additional information in the next downlink data frame and by cable 16 and sends next downlink data frame.After this, program 100 is returned square frame 102 and is waited for next uplink data frames.

Each subscriber station 14 ₁-14 _nPrograms shown in the execution graph 11A 200 all.When the program 200 of entering, square frame 202 makes its corresponding subscriber station wait comprise the next downlink data frame of range parameter R, minislot parameter MAP and affirmation (it is included as data slot distribution that this subscriber station is reserved).When receiving next downlink data frame, square frame 204 determines from minislot parameter MAP whether subscriber station that it is corresponding and other one or more subscriber stations have sent reservation request the same small time slot of the uplink data frames of going ahead of the rest, that is the reservation request collision that whether sends with one or more other subscriber station of the reservation request that sends of its corresponding subscriber station.Square frame 204 can pass through, for example, the small time slot that the subscriber station of its correspondence has therein been sent data in the uplink data frames of going ahead of the rest make with the small time slot comparison of in minislot parameter MAP, expanding and thisly determining (for example, by determine in uplink data frames in advance and therein its subscriber station small time slot that sent a reservation request whether to be endowed one in the downlink data frame that has just received be not 0 RQ number).

If square frame 204 is determined its corresponding subscriber station and other one or more subscriber stations and has sent reservation request that in the same small time slot of uplink data frames of going ahead of the rest square frame 206 determines from minislot parameter MAP whether its respective user station is allowed to send once more its contention data in advance next uplink data frames so.For example, the RQ number of the small time slot of uplink data frames in advance of the contention reservation request in advance that square frame 206 can be by sending the subscriber station of giving therein it it is counted comparison with the RQ that gives the small time slot of next uplink data frames and is made determining of it.If square frame 206 is not found the small time slot of coupling, square frame 206 determines not allow it to send its contention reservation request in advance once more so.On the other hand, if square frame 206 has been found the small time slot of a coupling, square frame 206 determines to allow to send once more its contention reservation request in advance so.

Therefore, if square frame 206 determines to allow to send once more its contention reservation request in advance, square frame 208 produces one in the random number N of giving within the expansion small time slot scope of its corresponding subscriber station so.That is to say, produce this random number N, make it equal in uplink data frames in advance, to send in the expansion small time slot of small time slot of contention data one (that is, making this random number N equal to have in the expansion small time slot with the identical RQ number of RQ number of the small time slot of giving the uplink data frames of going ahead of the rest that subscriber station (corresponding to square frame 206) wherein sent its contention reservation request) corresponding to corresponding therein subscriber station.Then, square frame 210 inserts contention reservation request in advance at the expansion small time slot N of the next uplink data frames that is used for transmitting.Square frame 212 resets a COL mark.

It should be noted that, if square frame 206 determines to give the maximum RQ number of the RQ number of the small time slot of uplink data frames in advance that its subscriber station wherein sent its contention reservation request of going ahead of the rest greater than the small time slot of giving next uplink data frames, square frame 208 produces a random number N, make this random number N equal one in next uplink data frames and have an expansion small time slot of the maximum RQ number of giving it.Then, square frame 210 inserts contention reservation request in advance in that expansion small time slot N.

On the other hand, square frame 206 can determine not allow its corresponding subscriber station to send its contention reservation request of going ahead of the rest (that is, its corresponding subscriber station has been assigned in the uplink data frames after of contention reservation request in advance who allows it to send it therein once more more leans on) once more in next uplink data frames.For example, if give in uplink data frames in advance and subscriber station therein (corresponding to square frame 206) sent its contention reservation request of going ahead of the rest the RQ number of small time slot less than the minimum RQ number of the small time slot of giving next uplink data frames, do not allow this subscriber station in this next uplink data frames, to send its contention reservation request in advance once more so.In this case, square frame 214 is set the COL mark.

If square frame 204 is determined its corresponding subscriber station and other one or more subscriber stations and is not sent reservation request in the same small time slot of this uplink data frames of going ahead of the rest that square frame 216 determines whether to have set the COL mark so.Shown in square frame 214, the COL mark is set when subscriber station has sent a reservation request unsuccessfully but do not allowed it to send this reservation request once more in next uplink data frames.Therefore, by during the program 200, square frame 216 allows square frame 206 to determine whether this subscriber station can send its contention reservation request in advance now once more at a subsequent process.If set the COL mark, program flow leads to square frame 206.

If square frame 216 determines not set the COL mark, or after square frame 214 has been set the COL mark, or make after the COL mark resets at square frame 212, square frame 218 (Figure 11 B) determine corresponding subscriber station whether (i) have data not send and (ii) also do not send a reservation request in advance for these data.If corresponding subscriber station (i) has data to send and (ii) also sent a reservation request for these data in advance, square frame 220 produces one by the transmission parameter RN within the scope that is included in the foundation of the range parameter R from the downlink data frame that initiating terminal 12 receives just.The scope of setting up by range parameter R can be comprise 0 and 0 and the R of R between scope, comprise 1 and 1 and the R of R between scope, or similar scope.This scope comprises all new message small time slots that are endowed 0 RQ number.Transmission parameter RN is used to determine whether to allow its corresponding subscriber station to send a new reservation request to initiating terminal 12.Transmission parameter RN can be produced as a random number by square frame 220.Therefore, because each subscriber station 14 ₁-14 _nWithin the scope of setting up by range parameter R, produce a self transmission parameters R N, subscriber station 14 as random value ₁-14 _nThe transmission possibility along the interval of range parameter R restricted portion by statistical distribution.

Whether the value that square frame 222 is determined the N that just produced by square frame 220 is corresponding to by one in the new message small time slot that is included in the definition of the minislot parameter MAP from the downlink data frame that initiating terminal 12 receives just.That is to say that if minislot parameter MAP is a map, square frame 222 is determined in the new message small time slot that whether value of N equal to define in the map one so.On the other hand, if minislot parameter MAP comprises the border between new message small time slot, expansion small time slot and the data slot, square frame 222 determines whether the value of N drops within the new message small time slot border so.If the value of N is corresponding to the new message part of minislot parameter MAP, square frame 224 is inserted into the value that equals N to a transmission reservation request and for transmitting back in the new message small time slot in the uplink data frames that initiating terminal 12 assembly get up so.

If square frame 222 determines that the value of N does not correspond to the new message part of minislot parameter MAP, if or square frame 218 determines that subscriber station does not need the new data of reservation request, or after square frame 224 was inserted into a reservation request in the new message small time slot with a value that equals N, square frame 226 was determined whether whether the downlink data frames that just received have reservation in subscriber station can send the next uplink data frames of legacy data therein data slot.Old data are meant has carried out the data of reservation request in advance of success by the appropriate users station for it, and initiating terminal 12 has been reserved one or more data slots for these data.If like this, square frame 228 inserts this legacy data in the data slot of initiating terminal 12 for this subscriber station reservation.

If square frame 226 is determined also not reserve a data time slot for this subscriber station in next uplink data frames, or legacy data being inserted in advance reservation request and after in the data slot reserved of one of a response at square frame 228, square frame 230 sends its part of next uplink data frames by cable 16.After this, program 200 is returned square frame 202 and is waited for next downlink data frame.

Therefore, the present invention is according to subscriber station request reasonable quantity ground allocation of channel resources may and a kind of dynamic search tree expansion process that up channel proposes being combined to solve the contention between the cell site.Along with having the quantity increase that sends the subscriber station of data to initiating terminal 12, the chance that bumps in uplink data frames has also increased.Along with the collision quantity in uplink data frames increases, the value of range parameter R is increased, and this will cause subscriber station can the possibility that a reservation request is inserted in the new message small time slot of a follow-up uplink data frames be reduced.In addition, along with having the quantity increase that sends the subscriber station of data to initiating terminal 12, the reservation request quantity in the reservation request formation DQ of initiating terminal 12 also increases.Along with the increase of the reservation request quantity among the reservation request formation DQ, the quantity of distributing to the small time slot of follow-up uplink data frames reduces.

Similarly, along with having the minimizing that sends the subscriber station quantity of data to initiating terminal 12, the chance that bumps in uplink data frames also reduces.Along with the collision quantity in uplink data frames reduces, the value of range parameter R reduces, and this will cause subscriber station can the possibility that a reservation request is inserted in the new message small time slot of a follow-up uplink data frames be increased.In addition, along with having the minimizing that sends the subscriber station quantity of data to initiating terminal 12, the reservation request quantity in the reservation request formation DQ of initiating terminal 12 also reduces.Along with the minimizing of the reservation request quantity among the reservation request formation DQ, the quantity of distributing to the small time slot of follow-up uplink data frames increases.

Therefore, when increasing along with the quantity of reservation request, initiating terminal 12 reduces the quantity of the small time slot of distributing to subscriber station, so that reduce the quantity of the reservation request of the success that subscriber station sends in uplink data frames.Along with the collision quantity in the small time slot of uplink data frames reduces, the value of range parameter R increases, and this has the effect that reduces permission subscriber station quantity of transmission reservation request in distributing to the new message small time slot of follow-up uplink data frames.Therefore, minislot parameter MAP and range parameter R acting in conjunction are suitably regulated data business volume in CATV system 10.

Meanwhile, utilize the dynamic tree retrieving to solve the contention that in new message small time slot and expansion small time slot, takes place.Therefore, the contention reduction has improved, and reduces to minimum reducing the required number of repetition of contention, and this has reduced the time delay in the transfer of data.

The use of RQ number has some advantages.For example, use the group address of a selection or specific specific address to give one group of selected subscriber station one 0 RQ number.In this way, can control the possibility that some selected subscriber station can send reservation request.Therefore, give 0 RQ number can for the subscriber station of limited quantity, to improve the possibility that they successfully send reservation request.

As selection, can utilize the group address of a selection or specific specific address to give 0 RQ number, so that only allow the subscriber station of the sort of type can successfully send reservation request for the subscriber station of particular type.Therefore, can read instrument between from the general off peak hours more after a little while of traffic carrying capacity at other type of user station.

Some improvement of the present invention more than has been discussed.Practice in the technology of the present invention field can be made other improvement to the present invention.For example, as mentioned above, each subscriber station determines that its transmission parameter RN is a random number, within the scope that this random number R N only is limited in being set up by range parameter R.As an alternative, can determine transmission parameter RN on the pseudorandom basis or on any other basis of tending to the transmission parameter RN of subscriber station is distributed in gamut R by each subscriber station.Therefore, be to be understood that producing at random of transmission parameter RN not only comprises the generation at random of transmission parameter RN, and comprise that the pseudorandom of transmission parameter RN produces, and with the generation of the transmission parameter RN of similar approach.

And, the size of uplink data frames and downlink data frame above be illustrated as fixing.But the size of uplink data frames and downlink data frame can dynamically be changed, and makes the size of these Frames for example, to change according to communication traffic load.

In addition, the special process that is used for determining range parameter R has more than been described.As an alternative, range parameter R can otherwise determine.For example, can determine range parameter R as the function of successful parameter S UC or as the two function of collision parameter COL and successful parameter S UC.

In addition, as mentioned above, when subscriber station had the data that will send, subscriber station used contention range parameter R in the transmission parameter RN that produces, and no matter the priority level of these data.As selection, when the data that have a low precedence when subscriber station will send, the transmission parameter RN that subscriber station can produce _LIn utilize contention range parameter R _LAnd the data that have a high precedence when subscriber station be will send the time, another transmission parameter RN that subscriber station can produce _HIn utilize a different contention range parameter R _HCorresponding to contention range parameter R _LTransmission parameter RN _LDetermine whether subscriber station can send the data of low precedence, corresponding to contention range parameter R _HTransmission parameter RN _HDetermine whether subscriber station can send the data of high precedence.Therefore, when the data that have a high precedence when subscriber station will send, can give their bigger chances that successfully sends reservation request.

Similarly, as described above, cable 16 is connected initiating terminal 12 and subscriber station 14 ₁-14 _nBetween.But, can connect initiating terminal 12 and subscriber station 14 with any communication media ₁-14 _n, twisted pair for example, optical cable, wireless transmission is utilized satellite, or the like.

As mentioned above, can determine the effectively quantity N at station from parameter S UC and/or COL.But, can use the quantity (that is, parameter EMP) of the empty slot from the uplink data frames of going ahead of the rest, or use parameter EMP at one, the combination of SUC and/or COL determines that effectively the method for station quantity N substitutes.

In addition, as mentioned above, can determine spreading coefficient E once more for every layer of contention.As an alternative, can determine spreading coefficient E, and can deduct fixing amount for follow-up contention layer thereafter according to the ground floor contention.

In addition, more than be of the present invention from the angle explanation of a kind of CATV system.But, be to be understood that the present invention can be used for various communication systems.

In addition, as mentioned above, if a uplink data frames will comprise small time slot, the new message small time slot of the minimum number that uplink data frames can have is NMS _MinIn order to hold the new message small time slot of this minimum number, preferably regulate the size of uplink data frames.If in the uplink data frames of a predetermined quantity, do not have enough expansion small time slots, also must regulate the size of uplink data frames to solve contention effectively.

In addition, the minimum number NMS of new message small time slot _MinNeed not to be fixing.As an alternative, at first determine the quantity of expansion small time slot, from the sum M S of small time slot, deduct the quantity of expansion small time slot then.If this subtraction result is to have the small time slot that can be designated as a new message small time slot, so a time slot is divided into m part again, to produce m+1 new message small time slot.Similarly, if this subtraction result is that two small time slots that can be designated as new message small time slot are arranged, so a time slot is divided into m part again, to produce m+2 new message small time slot, if this subtraction result is that three small time slots that can be designated as new message small time slot are arranged, so a time slot is divided into m part again, with m+3 new message small time slot of generation, or the like.Add a restriction can for this process, if make that subtraction result is when four small time slots that can be designated as new message small time slot are arranged, only to have four small time slots to be designated as new message small time slot.

In addition, as mentioned above, the contention behavior occurs in new message small time slot (NMS) the neutralization expansion small time slot (EMS).But the contention behavior can alternatively occur in such as new message time slot (NS) and expand in the so normal time slot of time slot (ES).

And as mentioned above, the contention behavior occurs in new message small time slot (NMS) the neutralization expansion small time slot (EMS).But the contention behavior can alternatively occur in such as new message time slot (NS) and expand in the so normal time slot of time slot (ES).In this case, can rewrite equation (1) according to following equation: $\mathrm{CS}(n+1)=M=\frac{S}{\frac{\mathrm{<figure-callout\; id="1"\; label="k\; e\; +"\; filenames="C97125714.000361.png"\; state="\{\{state\}\}">k</figure-callout>}}{e}+1}$

Wherein CS (n+1) is the sum of the contention slots in a Frame, and CS=NS+MS, n+1 represent next uplink data frames, and e is 2.718281828..., and k is that M is the stable state number of contention slots by the average of the data slot of reservation request reservation; Can rewrite equation (2) according to following equation:

CS(n+1)＝S-DQ(n)

Wherein DQ (n) is the quantity D Q (n) of the reservation request in the reservation request formation DQ of the initiating terminal 12 of time n; Equation (3) can rewrite according to following equation: $\mathrm{CS}(n+1)=M-\frac{\mathrm{DQ}\left(n\right)-\mathrm{\&alpha;DS}\left(n\right)}{6}$

Wherein DS (n) is the quantity of the data slot of the reservation in the uplink data frames that has just received; Equation (4) can rewrite according to following equation: $\mathrm{SUC}=\mathrm{NS}\frac{N}{\mathrm{NS}-1}{\left(\frac{\mathrm{NS}-1}{\mathrm{NS}}\right)}^N$

Wherein N is the quantity at new effective station, and NS is the sum of the new message time slot in the uplink data frames that has just received, and SUC is the quantity of the new message time slot of the non-NULL in the uplink data frames that does not wherein bump; And equation (5) can rewrite according to following equation: $\mathrm{COL}=\mathrm{NS}-\mathrm{NS}\frac{N}{\mathrm{NS}-1}{\left(\frac{\mathrm{NS}-1}{N}\right)}^N-\mathrm{NS}{\left(\frac{\mathrm{NS}-1}{\mathrm{NS}}\right)}^N$

Wherein N is the quantity at new effective station, and NS is the sum of the new message time slot in the uplink data frames that has just received, and COL is a quantity in a uplink data frames that has just received and new message time slot that wherein bump.Therefore, except as otherwise noted, time slot described here comprises complete time slot, part time slot, small time slot, or similar time slot.

Therefore, description of the invention only is in order to illustrate and to tell those of ordinary skill in the art to implement the purpose of optimal mode of the present invention.Can carry out substantial change and not break away from spirit of the present invention its details, and be reserved in all interior improved exclusive rights to use of claim scope.

Claims (15)

1. station comprises:

Be used to receive the receiving system of downlink data frame with a range parameter R and a parameter MAP, wherein parameter MAP has defined a plurality of new message small time slot NMS in next uplink data frames, a plurality of expansion small time slot EMS and a plurality of data slot DS by a dynamic search tree expansion process expansion;

Be used to produce the transmission parameter generation device of a transmission parameter RN, wherein transmission parameter RN is subjected to the constraint of range parameter R; With

Emitter is used for sending a reservation request in the new message small time slot in next uplink data frames as transmission parameter RN during corresponding to new message small time slot; Be used for when this station sent a reservation request in one is gone ahead of the rest uplink data frames and small time slot that be expanded in next uplink data frames, in an expansion small time slot of next uplink data frames, sending a reservation request once more; And during the data slot that is used for reserving, in this data slot, send data when promising this station.

2. station as claimed in claim 1, wherein next uplink data frames has S time slot, and one of them time slot is divided into m small time slot and S=(NMS+EMS)/m+DS wherein.

3. station as claimed in claim 1, wherein as transmission parameter RN during corresponding to a new message small time slot, emitter sends a reservation request, and when transmission parameter RN did not correspond to range parameter R, emitter abandoned sending a reservation request.

4. station as claimed in claim 1, wherein transmission parameter RN is a random number.

5. station as claimed in claim 1, wherein EMS is based on the quantity at effective station.

6. station as claimed in claim 1, wherein EMS is a fixing number.

7. station as claimed in claim 5, wherein effectively the quantity at station is determined by following equation: $\mathrm{SUC}=\left({\mathrm{MS}}_L\right)\left(\frac{N}{{\mathrm{MS}}_L-1}\right){\left(\frac{{\mathrm{MS}}_L-1}{{\mathrm{MS}}_L}\right)}^N$

Wherein N is the quantity of effectively standing, MS _LBe the sum of the small time slot in a contention layer of uplink data frames in advance, SUC is the quantity of the non-NULL small time slot in the contention layer of the uplink data frames in advance that do not bump therein.

8. station as claimed in claim 5, wherein effectively the quantity at station is from generally a look-up table corresponding to following equation is definite: $\mathrm{SUC}=\left({\mathrm{MS}}_L\right)\left(\frac{N}{{\mathrm{MS}}_L-1}\right){\left(\frac{{\mathrm{MS}}_L-1}{{\mathrm{MS}}_L}\right)}^N$

Wherein N is the effective quantity at station, and MS is the sum of the small time slot in a contention layer of uplink data frames in advance, and SUC is the quantity of the non-NULL small time slot in the contention layer of the uplink data frames in advance that do not bump therein.

9. station as claimed in claim 5, wherein effectively the quantity at station is determined by following equation: $\mathrm{COL}={\mathrm{MS}}_L-\left({\mathrm{MS}}_L\right)\left(\frac{N}{{\mathrm{MS}}_L-1}\right){\left(\frac{{\mathrm{MS}}_L-1}{N}\right)}^N-\left({\mathrm{MS}}_L\right){\left(\frac{{\mathrm{MS}}_L-1}{{\mathrm{MS}}_L}\right)}^N$

Wherein N is the quantity of effectively standing, and MS is the sum of the small time slot in the contention layer of uplink data frames of going ahead of the rest, and COL is the quantity of the small time slot in the contention layer of the uplink data frames in advance that has just received and wherein bump.

10. station as claimed in claim 5, wherein effectively the quantity at station is from generally a look-up table corresponding to following equation is definite: $\mathrm{COL}={\mathrm{MS}}_L-\left({\mathrm{MS}}_L\right)\left(\frac{N}{{\mathrm{MS}}_L-1}\right){\left(\frac{{\mathrm{MS}}_L-1}{N}\right)}^N-\left({\mathrm{MS}}_L\right){\left(\frac{{\mathrm{MS}}_L-1}{M{S}_L}\right)}^N$

Wherein N is the quantity of effectively standing, and MS is the sum of the small time slot in the contention layer of uplink data frames of going ahead of the rest, and COL is the quantity of the small time slot in the contention layer of the uplink data frames in advance that has just received and wherein bump.

11. station as claimed in claim 1, wherein EMS is based on the quantity of the small time slot in the upstream data message that wherein bumps.

12. station as claimed in claim 1, wherein emitter comprises:

Be used for selecting randomly the device of an expansion small time slot; With

Be used for inserting the device of reservation request at the expansion small time slot of selecting at random.

13. station as claimed in claim 12, wherein EMS is based on the quantity of the small time slot in the upstream data message in advance that wherein bumps.

14. station as claimed in claim 1, wherein next uplink data frames have the individual small time slot of MS (n+1) and MS (n+1)=NMS+EMS wherein.

15. station as claimed in claim 14, wherein:

When DS (n)＜DQ (n)＜α DS (n), $\mathrm{MS}(n+1)=M=\frac{S}{\frac{k}{e}+\frac{1}{m}}$

Wherein MS be in the Frame of discrete time n+1 and corresponding to the quantity of the small time slot of parameter MAP, DS (n) is the quantity of the data slot in the Frame of discrete time n, DQ (n) is the quantity in pending reservation request such as discrete time n, α is a constant, M is the quantity at the small time slot of stable state, S is the quantity of the time slot in a Frame, k is the number corresponding to an average of the data slot of being reserved by reservation request, and m is the quantity of the small time slot that can be divided again of a time slot of a Frame;

When DQ (n)＜DS (n),

MS (n+1)=m (S-DQ (n)); With,

When DQ (n)＞α DS (n), $\mathrm{MS}(n+1)=M-m\frac{\mathrm{DQ}\left(n\right)-\mathrm{\&alpha;DS}\left(n\right)}{6}.$

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