WO2002032162A2

WO2002032162A2 - System and method for adaptive communication

Info

Publication number: WO2002032162A2
Application number: PCT/JP2001/008985
Authority: WO
Inventors: Riaz Esmailzadeh; Kambiz Homayounfar
Original assignee: Genista Corporation
Priority date: 2000-10-13
Filing date: 2001-10-12
Publication date: 2002-04-18
Also published as: WO2002032162A3; AU2001294243A1

Abstract

A system, method and apparatus for dynamically maintaining perceptual quality of service are described. Using metrics gathered in real time by a receiver correlated with a user's perceived quality, a transmitter adjusts parameters to maintain a predetermined level of transmission quality. Network providers dynamically allocate limited network resources by adjusting transmission parameters in real time, thereby maximizing resource allocation, and by offering subscribers different prices correlated to quality, maximizing the revenue generation of the network.

Description

DESCRIPTION

SYSTEM AND METHOD FOR ADAPTIVE COMMUNICATION (Technical Field) The present invention relates to the transmission of signals over a communications network, and more particularly to the use of metrics identifying humanly perceptible variations in the transmission of a signal to adjust the quality level of the signal.

(Background Art)

Communications networks of various types are becoming increasingly popular in our society as the rapid and accurate exchange of information becomes increasingly important to our economy. These networks include the Internet, wherein data is broken into packets, transmitted and reassembled in the proper order by the location receiving the information, traditional telephone systems using Public Switched Telephone Network (PSTN), and wireless mobile communications networks.

A number of environmental factors can significantly affect the transmission of real time data, such as streaming video and voice, over communication networks. For instance, as a cellular wireless network approaches its transmission capacity, the probability that a call may be dropped or that frames of voice or data may be lost increases significantly. Furthermore, the location of a cellular receiver relative to a transmission station may cause frames of data to not be received. In IP networks, buffer overflow in routers and switching stations may cause them to refuse to accept and forward packets of data. These environmental factors can and do often result in degradation in the quality of a transmission that is perceptible to the users of a network. The perceptual quality of services can directly affect providers ' ability to attract and retain customers. Furthermore, the perceptual quality of the service relates to the fees the provider can charge in the market place. Most communications networks provide mechanisms for selecting the transmission parameters between two or more connected devices. For instance, in a Code Division Multiple Access (CDMA) cellular network, the transmitter will, based on information received from the receiver, for example, adjust the power level of its transmission to the receiver in order to preserve the signal integrity at the receiver. Two modems in a PSTN network will set transmission protocols when establishing a connection therebetween based on the condition of the transmission line. In an TCP/IP network, the receiver of packetized data will signal a transmitter to retransmit packets it has received containing errors or packets it has failed to receive. Unfortunately, these types of adaptations do not directly relate to the transmissions' perceptual quality relative to a user of the receiving device. In the case of a CDMA's adaptive power control (APC), the frame erasure rate (FER) does not directly relate to perceived quality. For instance, a high FER may not degrade the perceived quality of a transmission if the frames are dropped in isolation relative to each other; whereas , a transmission with a low overall FER may cause a perceivable portion of a voice transmission to be lost if a concentration of frames are dropped consecutively or in close proximity to each other. In a TCP/IP network, the dropped, lost or incomplete packets are resent by the transmitter in response to an indication by the receiver, yet the retransmission of a packet does not ensure that the packet will be received in a timely manner to obviate any potential perceived quality problems that the missing packet and other associated missing packets may cause.

In a User Datagram Protocol (UDP) transmission, such as a number of protocols used for transmission of voice over an IP network, packets are not retransmitted and, therefore, may be lost. Packets may also be received with a delay of a time that is longer than is allowed and automatically discarded. Accordingly, potential perceptual quality problems arise.

Static and dynamic approaches have been utilized to improve the perceptual quality of service (PQoS) of a network transmission; however, the metrics used in determining whether to effect changes to the network do not relate directly to the perceptual quality of a transmission as experienced by a user of the service of the network. Furthermore, conventional technology in this art does not provide a mechanism for adjusting the performance of a particular network connection, i.e., a cellular phone call, dynamically, either up or down during the connection to maintain a particular quality level without unnecessarily tying up network resources in doing so.

(Disclosure of Invention)

(Brief Description of Drawings)

The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, explain the advantages and principles of the invention. In the drawings, FIGURE 1 is a generalized illustration of a wireless cellular network;

FIGURE 2 graphically represents how the real time perceptual quality level of a voice transmission may vary over time; FIGURE 3 is a block diagram of a base transceiver and a mobile transceiver in communication over a wireless network according to one embodiment of the present invention;

FIGURE 4 is a flow diagram illustrating a method for adaptively adjusting transmission protocols from a network device based upon perceptible metrics ;

FIGURE 5 illustrates in a graphical format how a signal can be adjusted to a selected level according to embodiments of the present invention; and FIGURE 6 graphically illustrates how the transmission rate of a voice signal may vary during a call according to an embodiment of the present invention.

(Best Mode for Carrying Out the Invention) The numerous innovative teachings of the present application will be described with particular reference to the presently preferred exemplary embodiments. However, it should be understood that this class of embodiments provides only a few examples of the many advantageous uses of the innovative teachings herein. In general, statements made in the specification of the present application do not necessarily delimit any of the various claimed inventions. Moreover, some statements may apply to some inventive features but not to others . A method and apparatus for dynamically maintaining perceptual QoS of communication over a network at a relatively constant level to a user are described. Based on metrics gathered in real time by a receiver that can be directly correlated to a user's perceived quality, a transmitter adjusts its transmission parameters to either increase or decrease the quality level of the transmission to maintain the quality level as close as possible to a predetermined level. Advantageously, network providers can offer differing service plans based on a user's particular needs, wherein users requiring the best possible service pay more than users who are willing to sacrifice quality for a reduced cost . Network providers can dynamically allocate limited network resources by adjusting transmission parameters in real time to maximize the revenue generating potential of the network.

Exemplary embodiments of the invention are described herein primarily in terms of voice communications over a W-CDMA-based mobile communications network. It is to be appreciated that this invention is also applicable to other types of multimedia communication, such as audio or video, over other than types of, communications networks including but not limited to CDMA, CDMA2000, TCP/IP, asynchronous transfer mode (ATM) and PSTN networks. With reference now to FIGURE 1 of the Drawings, a portion of a CDMA cellular network, as can be utilized with CDMA and W-CDMA technology, is diagrammatically illustrated and generally designated by the reference numeral 100. The network 100 is divided into a number of cells 110 that indicate the typical area of coverage for a base transceiver 120 located in the middle of each cell. Other base transceiver 120 and cell 110 arrangements are possible as would be known to one of ordinary skill in the art. Each base transceiver 120 within the cellular network is coupled to one or more central stations 130 for communication therewith. Each central station 130 facilitates communication between base transceiver 120 to coordinate operations concerning certain tasks , such as handing off a mobile transceiver 150 from one cell to another. Each central station 130 includes or is coupled to a switching center 140. The switching center is typically coupled to a PSTN 145.

Operationally, voice signals are transmitted between a mobile transceiver 150, such as a cellular phone, and the base transceiver 120 located within an associated cell 110. In a spread spectrum network such as CDMA and W-CDMA, the signal is transmitted between the mobile and the base transceivers 120 and 150 over the entire available bandwidth. Each signal is identified by a code, which specifies a specific order of frequency sequencing within the band, such that the base or mobile transceivers 120 and 150 can decipher the voice signal and relay it to the user. A relatively large number of distinct coded signals can be transmitted simultaneously in any particular cell 110 over the available spectrum. As a mobile transceiver in a CDMA network passes through a region where two or more cells overlap, such as regions 160 and 170, the base transceivers 120 associated with the overlapping regions 160 or 170 can transmit to and receive signals from the mobile transceiver 150 simultaneously. As the mobile transceiver 150 leaves the overlapping regions 160 and 170 and at least one of the cells 110, the mobile transceiver 150 will continue to communicate with the base transceiver 120 associated with the cell 110 in which it is located and communication with the other base transceiver(s) 120 will cease. This process is known as a "soft handoff". By using a "soft handoff", the probability that a call will be dropped as the mobile transceiver 150 moves from one cell 110 to another is reduced since the mobile transceiver 150 establishes communication with the cell 110 into which it is moving before ending communication with the cell 110 it is leaving. Conversely, the probability that the call will be dropped in a hard handoff situation is greater since the "new" cell 110 that the user is moving into may not have capacity for the user that it would been able to set aside had the base transceiver 120 associated with the cell been aware of the possibility of the user's arrival therein. As can be appreciated, the use of a "soft handoff" can act to limit the overall capacity of the CDMA network 100 slightly since a portion of the capacity of each of the overlapping cells 110 is being utilized by a single user concurrently.

Prior to transmitting the voice signal over a wireless connection to a transceiver 120 or 150, the signal is typically compressed by a vocoder (voice coder) , It can be appreciated that by compressing the size of a voice signal prior to transmission, the total number of signals that may be supported in a limited bandwidth environment can be increased. However, as a voice signal is compressed, its perceptual quality degrades as well. In first generation CDMA networks , the voice signal is typically compressed for transmission at a rate of about 8 kbs. The vocoders in W-CDMA and CDMA2000, however, permit several different compression levels of voice encoding ostensibly to allow network operators to offer plans to customers based on a chosen level of encoding. Voice signals that are more highly compressed on average exhibit lower levels of perceived quality than those that are compressed less. However, depending on other noise generating factors that affect two different WCDMA signals, a more highly compressed signal may exhibit a greater perceived quality than a less compressed counterpart at a given point in time within a transmission. Although the ability to utilize different voice signal compression levels is provided in WCDMA and CDMA2000 networks, the prior art does not provide a means for adjusting the encoding compression levels dynamically to improve perceptual QoS. Since CDMA involves the transmission of many signals over the same frequency spectrum simultaneously, the strength of each transmission signal received by a transceiver 120 or 150 must be similar to the strengths of the other signals being transmitted over the frequency spectrum simultaneously. If the signals received at a transceiver have different signal strengths, a stronger signal which represents background noise to another weaker signal could overpower the weaker signal and cause static or other perceptible quality problems to the users carrying on a communication associated with the weaker signal. This issue is known by those of ordinary skill in the art as the "Near-Far Problem".

The strength of a signal received at a receiving transceiver is dependent on several factors, including a transmitting transceiver's distance from the receiving transceiver, obstacles located between the transmitting and receiving transceivers, and the power level at which the transmitter is broadcasting. Accordingly, by sampling the signal strength received by the receiving transceiver from a transmitting transceiver and adjusting the transmission power relative to the signal strength, a base and mobile transceiver 120 and 150 can maintain associated signal strengths at a fairly constant level relative to other signals being transmitted within the cell 110. It is to be appreciated that by increasing the transmission power levels between a mobile transceiver 150 and a base transceiver 120 relative to other mobile transceivers 150 within the cell 110, the quality of that signal will increase, although the noise generated by the higher-powered signal would correspondingly decrease the signal quality of the other mobile transceivers 150.

Unlike Advanced Mobile Phone Service (AMPS) and Time Division Multiple Access (TDMA) networks within which the maximum number of simultaneous users within a cell can be fairly precisely defined, the number of users in a CDMA network can be varied depending on how the cell is being affected by interference within the cell and from surrounding cells . The ability to vary the capacity of the cell dynamically is referred to as "soft capacity".

For example, when the interference from neighboring cells is low because of low usage in the neighboring cells, the ultimate capacity of a cell may be increased. Conversely, when usage is high in neighboring cells and that usage is causing interference in a cell, the cell can reduce its maximum capacity. It is to be understood that the soft capacity does not only relate to the number of simultaneous users active within a cell, rather it also relates to total bit rate transmission capacity available from a cell as an aggregate of all users within that cell. Accordingly, a cell can support a greater number of low bit rate users (i.e., users having their voice data streams more highly compressed by the vocoder) than high bit rate users (users having less compressed voice data streams or users streaming data at high bit rates) for a given maximum soft capacity.

As the numbers of simultaneous users within a cell 110 is increased, the power available from the base transceiver 120 for each mobile transceiver 150, particularly those far from the base transceiver, is reduced. To account for this, the cell is capable of dynamically reducing its area of coverage. The ability to vary the geographic coverage of the cell dynamically is referred to as "soft coverage." It can be appreciated that a base transceiver 120 of a cell 110 with a limited amount of transmission power to be distributed among simultaneous mobile transceivers 150 can support a greater number of mobile transceivers when most of the mobile transceivers are close to the base transceiver than when most of the mobile transceivers are located far from the base transceiver.

The mechanisms described above permit the CDMA and/or W-CDMA network provider to dynamically vary the transmission parameters for the network 100 as a whole, for all the mobile transceivers 150 within a particular cell 110, or for a single mobile transceiver 150. Current networks however, do not utilize metrics that can be related to the QoS as it will be perceived by a user of the network. Rather, typical communications networks rely on a handful of simple indicators to adjust the performance of a network that in isolation do not relate to the perceptual QoS of a signal.

One of the primary metrics utilized by the base transceiver 120 in a CDMA or W-CDMA network 100 to determine the relative strength of a signal being received both by and from a mobile transceiver 150 is a measure of the frame erasure rate (FER) . The FER describes the number of data frames that were erased by a receiving transceiver due to bit errors during transmission that could not be recovered or due to frames that were never received as may be the cause in regards to streaming traffic from a server over the Internet. As the FER increases, a decrease in received signal strength relative to the "noise" generated by the other signals within the cell is indicated. The frame erasure rate does not directly relate to the real time quality level perceived by the user of a mobile transceiver 150. It can be appreciated that random frames that are erased in isolation (i.e., those erased frames that are preceded and followed by a number of consecutive correctly received frames) are unlikely to have a significant effect on perceived quality even if a significant percentage of frames are erased (e.g., greater than 1%). Conversely, frames that are erased consecutively or in close proximity to each other would likely result in a reduction of a user's perceptual QoS.

The primary measure of voice quality used within the wireless telephone industry is the Mean Opinion Score (MOS). A MOS is the result of a subjective listening test, wherein listeners compare various samples generated from voice streams and assign a quality value of 1 to 5 thereto. The MOS is an arithmetic mean determined from a large number of samples for a particular voice stream. Typically, MOSs have been used to characterize the relative quality of vocoder compressed voice streams, although MOSs can also be used to determine the perceived transmission quality for wireless voice streams, subject to a variety of conditions. As a point of reference, land lines transmitting at 16 kbps typically have MOSs of around 3.6-3.7; whereas, voice signals compressed to 4.75 kbps for wireless transmission have MOSs around 3.2. Since the traditional method of generating an MOS score requires a large sample of people listening to and rating a transmission, it is obviously not practical to make real-time measurements of voice quality. Using this methodology to dynamically adjust network transmission parameters in real time, MOSs are therefore typically limited to use in developing best practices scenarios for voice streams transmitted under certain predetermined conditions.

With reference now to FIGURE 2, there is a graphical representation of how the real time perceptual quality level of a CDMA voice transmission may vary over time depending on the various factors affecting the FER of the associated voice stream. Line 210 represents MOS quality levels 220 that may be perceived by a user at certain points along a timeline 230 during a CDMA network voice transmission. Environmental factors, such as the location of the user relative to a transceiver shadowing and other fading effects, can significantly affect perceptual QoS. For instance, the perceptual quality may drop as indicated at time 240 when a user is deep within a building where the signal has difficulty penetrating through walls. Additionally, as the number of simultaneous users within a cell 110 increases, the noise level may increase, along with the FER, thereby reducing the perceptual QoS. Conversely, the perceptual QoS may increase to relatively high levels as shown at time 250 when a user is located close to the base transceiver 120 and there are a minimal number of simultaneous users within the cell 110.

With reference now to FIGURE 3, there is illustrated a block diagram of a system for (1) measuring metrics that correlate to a user's perceptual QoS and (2) making adjustments to the transmission protocols to adaptively change the perceptual QoS of the voice stream in real time according to one embodiment of the invention. Related FIGURE 4 is a flow diagram illustrating a method for adaptively adjusting the transmission protocols of a network device based on metrics that correlate with the user's perceptual QoS according to one embodiment of the invention.

Referring to block or step 405 of FIGURE 4, communication channels are established between a base transceiver 120 and a mobile transceiver 150, as illustrated in FIGURE 1. At least two channels 310 and 320 are established on initiation of a telephone call, as illustrated in FIGURE 3. One channel serves to transmit a voice stream from the base transceiver 120 to the mobile transceiver 150 and is referred to herein as the downlink channel 310. The other channel serves to transmit voice stream data and data to the base transceiver 120 from the mobile transceiver 150, and is known as the uplink channel 320. At least two channels are required for a full duplex communication, although in alternative embodiments communication between the transceivers can be established over additional channels. For instance, a third or fourth channel can be established solely for the purpose of transmitting channel control data between the transceivers , where the uplink 320 and downlink channels 310 are used only to transmit voice signals.

With reference now to block or step 410 in FIGURE 4, the base transceiver 120 transmits a compressed voice signal to the mobile transceiver 150. As can be appreciated, the voice signal may originate from a PSTN signal sent to the base transceiver 120 through a switching center station 140, which is ultimately in communication with a device, such as a telephone connected to the PSTN network, generally designated in FIGURE 4 by the reference numeral 145, or the call may originate from another mobile transceiver 150 in communication with the base transceiver 120 through other channels. As shown in FIGURE 4, the signal is received by the mobile transceiver 150, as indicated in block 415. As described above, the voice signal is transmitted at constantly varying frequencies over the entire bandwidth available to the CDMA, W-CDMA or CDMA2000 network, as is well understood in this art. Each channel is identified by a code, which uniquely specifies its signal over the shared band.

The voice signal, upon receipt, is forwarded to and decompressed by a vocoder 330 in the mobile transceiver 150, as indicated by block 420 in FIGURES 3 and 4. The vocoder 330 is preferably resident in software that utilizes a processor or processing unit, generally designated by the reference numeral 390, contained within the mobile transceiver 150, although it should be understood that in alternative embodiments the vocoder 330 can be resident in dedicated hardware. The decompressed signal is then forwarded to and transmitted by a speaker 340 for audio transmission to the user of the mobile transceiver 150, as shown in block 425. Referring to block 430, which may occur concurrently or in close proximity therewith with audio playback to the user (step 425), the decompressed voice signal is analyzed by a voice signal analyzer 350 to determine perceptual QoS metric values concerning anomalies in the voice stream that are humanly perceptible. Software to measure perceptual voice quality has been recently made available, known as MultiVQ and DualVQ, developed by Genista Corp. of Japan, the assignee of the present invention. Dual-VQ, for example, is a voice quality tool that is run on a windows platform to analyze voice files for various numerical or digital characterizations of audio anomalies that a user would perceive. In particular, Dual-VQ detects and measures voice choppiness, delay variation (jitter), and variations in active speech levels. Dual-VQ then provides a variety of metrics describing the quality of the analyzed voice stream, including an MOS metric. The MOS metric generated by Dual-VQ has been found to exhibit a 97% correlation with MOSs derived by traditional methods. It is within the ordinary level of skill of someone in the software and programming arts to port a version of the voice tools for operability within a cell phone for use by a microprocessor contained within the cell phone. By using this type of software tool resident in the mobile transceiver 150, voice signals can be analyzed in real time with metrics being generated that directly correlate to humanly perceptible variations in the quality of a voice signal. In the simplest form, the resulting metric may be a single number indicating the overall quality of the voice signal similar to a MOS, or a more sophisticated set of data may be obtained that individually describes the various anomalies within the voice stream.

With reference again to FIGURES 3 and 4, in step or block 435, the resulting data concerning perceptual QoS is transmitted over the uplink channel 320 to the base transceiver 120. Upon receipt, the base transceiver 120 uses the data to adjust channel and network parameters based on the data, as indicated by step or block 440. In an alternative embodiment, the data may be transmitted to the base transceiver 120 over a dedicated data link instead of over the uplink channel 320 with voice signals, In certain embodiments , the data is utilized to maximize the quality of a voice signal sent to a particular mobile transmitter 150. In other embodiments, the data is utilized to adjust the quality of the voice signal either upwardly or downwardly to match a particular level associated with a user of a particular mobile transceiver 150. For example, a business person may desire the best possible level with regard to his mobile phone, and may be willing to pay a premium for a guarantee that he will have the best possible signal. In this instance, the base transceiver 120 will adjust the transmission characteristics concerning the business person to maximize quality. On the other hand, a college student may be willing to live with a lower level of signal quality in return for an inexpensive rate plan. In this instance, the base transceiver may adjust the college student's signal quality downwardly, e.g., upon network congestion and/or when the quality level exceeds the student ' s subscribed level .

With reference now to FIGURE 5, there is illustrated in graphical format how a signal might be adjusted during a phone call to match the perceptual QoS characteristics of the voice signal as closely as possible with the user's subscribed level. Line 510 indicates the relative quality level of the signal in terms of a metric, as it would be experienced without the use of a perceptual QoS adaptive system. Line 520, on the other hand, indicates the level after the adjustment of applicable transmission parameters, such as, but not limited to, the power level of the voice signal transmission, the soft capacity of the cell, the soft coverage of the cell, and the compression level of the voice signal. For example, at time 530 where the level is higher than the user's contracted level (assuming the user contracted for a "fair" level) , the vocoder 330 in the base transceiver 120 may be directed by the base transceiver's processing unit, generally designated by the reference numeral 390, to increase the level of compression of the voice signal to lower the user's, thereby freeing up capacity within that particular cell for use by other users. At time 540, however, when the unadjusted perceptual QoS level is significantly below the contracted level, the processing unit 390 within base transceiver 120 would initiate parameter adjustments to increase the user's perceptual QoS, such as directing a power controller 360 within the base transceiver 120 to boost the power of the signal transmitted to the user, and/or decreasing the amount of vocoder 330 compression. At time 550, the entire cell 110 may be experiencing greater than acceptable levels of noise as compared to neighboring cells, in which case the base transceiver's processing unit 390 may direct a capacity controller 380 and a soft coverage controller 370 to decrease the geographic coverage and capacity of the cell to improve the perceptual QoS of all the active mobile transceivers 150 located within the cell 110. With reference now to FIGURE 6, there is illustrated how the compression level used by the base transceiver vocoder 330 may vary during a telephone call in a W-CDMA network. The vocoder 330 utilized in a W-CDMA is capable of compressing a voice signal into one of a plurality of rates from 4.75 kbs to 12.2 kbs. Depending on the metrics provided by a mobile transceiver, the base transceiver can dynamically adjust the compression rate accordingly. For example, line 610 shows the voice signal rate at various points during a 20 second timespan of a telephone call. CDMA 2000, another version of a CDMA network, also utilizes a vocoder 330 capable of adjusting compression levels of a voice stream before transmission thereof.

As indicated in the methodology illustrated in FIGURE 4 and described in the accompanying text, the perceptual QoS of a voice transmission is continuously monitored in real time to detect variations in the quality of the signal and make the proper adjustments before any change in the perceptual QoS becomes noticeable to a user. As can be appreciated by one skilled in the art, the sampling rate of the voice signals pursuant to the principles of the present invention can be varied as can the duration of the sampled portions of a voice transmission. Although sampling short duration portions of the voice stream is within the capability of current art electronics, it is preferred in embodiments of the invention that analyzed portions of the voice stream be of sufficient duration, typically a second or greater, such that problems that would be perceptible to a human can be identified.

As illustrated in the example above, metrics can be utilized to both (i) make a determination whether to adjust the perceptual QoS of a single mobile transceiver within a cell, and (ii) make a determination whether to adjust the transmission characteristics of the cell 110 as a whole. Furthermore, the metrics can be utilized by a central base station controller 130 to adjust the relative levels in one cell compared to another neighbor's cell. For example, if most of the users in a first cell are experiencing levels in excess of their contracted levels and the users in a neighboring second cell are simultaneously experiencing levels below their contracted levels, the central base station controller 130 can direct the poorly-performing first cell to contract and reduce its capacity, while directing the second cell to expand its coverage and capacity to include those users that will be placed outside of the first cell's new coverage area. Accordingly, the levels of users in both cells can be harmonized as the levels in the first cell increase and the levels of the users in the second cell decrease.

The present invention has been described above concerning an embodiment wherein a cellular base station adjusts its transmission parameters based on humanly perceptual metrics received from a mobile transceiver regarding voice signals sent from the base transceiver. Embodiments of the invention may, however, be also applied in reverse, wherein the mobile transceiver 150 adjusts it voice signal transmission parameters based on metrics received from respective base stations 120. It should further be understood that the use of humanly perceptible metrics can be utilized in conjunction with communications networks of many different types and is not limited to use in the CDMA and WCDMA networks described herein. Furthermore, although described in relation to voice signals , embodiments of the present invention are contemplated for use with any type of signal transmitted over a communications network wherein variations in the receipt of the signal are humanly perceptible, such as but not limited to any multimedia signal that is experienced in real time.

For example, the principles of the present invention may be employed in governing the intercommunications between two devices within a communications system. A first and second device, such as the base transceiver 120 and mobile transceiver 150 in FIGURES 1 and 3, may instead constitute two devices or nodes in a landline system or combined landline/wireless system. High bandwidth communications , such as visual images , movie images and multimedia data, may therefore be streamed employing the techniques of the present invention, i.e., (1) identification of at least one humanly perceptual or perceptible variation in the signal stream, whether audio or visual, e.g., in relation to a predetermined level of transmission quality, and (2) modification or adjustment of the transmitter's parameters or protocols to correct or ameliorate the humanly perceptual variation, e.g., to better accord with the predetermined level of transmission quality. Conformation of the transmitted signal to the baseline or target level of quality reduces the perceived flaws in transmission, which a customer may pay extra for. Conversely, deviation from an optimal or target measure may be in order for other users less desirous of optimal quality. Although the present invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made by way of example, and changes in detail or structure may be made without departing from the spirit of the invention, as defined in the appended claims.

The present application claims priority from United States provisional patent application, U.S. Serial No. 60/240,530 entitled, "System and Method for QoS Adaptive Communications," filed on October 13, 2000, which is incorporated herein by reference as if fully set forth.

(Industrial Applicability)

The present invention is applied to the transmission of signals over a communications network, and more particularly to the use of metrics identifying humanly perceptible variations in the transmission of a signal to adjust the quality level of the signal.

Claims

CLAIMS 1. In a communications network, a method for maintaining perceptual quality of service between a transmitter and a receiver within said communications network, said method comprising the steps of: receiving a first data signal from said transmitter at said receiver over said communications network, said first data signal having at least one humanly perceptual variation therein, said at least one humanly perceptual variation being based on the quality of said first data signal as received at said receiver; dynamically detecting, at said receiver, said at least one humanly perceptual variation in quality of said first data signal; receiving a dynamic adjustment from said receiver at said transmitter over said communications network, said dynamic adjustment modifying at least one transmission protocol of said transmitter based on said at least one humanly perceptual variation; and transmitting a second data signal from said transmitter to said receiver, said second data signal having said at least one humanly perceptual variation therein, said at least one humanly perceptual based on the quality of said second data signal as received at said receiver and an adjusted one of said at least one transmission protocols, whereby the quality of said second data signal is closer to a predetermined level of transmission quality than said first data signal.

2. The method according to claim 1 , wherein said communications network is a code division multiple access (CDMA) wireless network.

3. The method according to claim 1 , wherein said communications network is a time division multiple access (TDMA) network.

4. The method according to claim 1, wherein said dynamic adjustment is transferred over a dedicated data channel, said dedicated data channel being distinct from channels of said communications network utilized to transmit said first and second data signals.

5. The method according to claim 1, wherein said first and second data signals comprise voice data.

6. The method according to claim 5, wherein said at least one humanly perceptual variation is selected from the group consisting of: audio distortion, audio choppiness, audio jitter, variations in audio level and combinations thereof .

7. The method according to claim 1 , wherein said first and second data signals comprise audio data.

8. The method according to claim 1 , wherein said first and second data signals comprise video data.

9. The method according to claim 8 , wherein said at least one humanly perceptual variation of said video data is selected from the group consisting of: uneven frame rate resulting in picture jerkiness, audio cut outs or distortion, poor image quality, missing or incomplete video frames, and combinations thereof.

10. The method according to claim 8, wherein said video data comprises multimedia information.

11. The method according to claim 2, wherein said at least one transmission protocol comprises a transmission power level for said transmitter.

12. The method according to claim 2, wherein said at least one transmission protocol comprises the transmission rate.

13. The method according to claim 5, wherein said at least one transmission protocol comprises the level of compression of the first and second data signals.

14. The method according to claim 1, wherein said receiver is a client computer and said transmitter is a server computer.

15. The method of operating a network device within a communications network, said method comprising the steps of: receiving, at said network device from the communications network, a signal containing therein realtime multimedia information, said multimedia information containing therein at least one humanly perceptual variation, said at least one humanly perceptual variation being based upon the quality of the multimedia information as received at said network device; and generating, within said network device, at least one signal metric based upon the quality of said multimedia information as received, whereby said signal metric contains at least one adjustment to at least one transmission protocol of a source device within said communications network.

16. The method according to claim 15, further comprising the step of: transmitting, by said network device to said source device in said communications network, said at least one adjustment to said at least one transmission protocol.

17. The method according to claim 15, wherein the communications network is a code division multiple access wireless network.

18. The method according to claim 15, wherein the communications network is a time division multiple access wireless network.

19. The method according to claim 15, wherein the signal metric is transferred over a dedicated data channel, said dedicated data channel being distinct from channels of said communications network utilized to transmit signals comprising multimedia information.

20. The method according to claim 15, wherein said multimedia information comprises voice signals.

21. The method according to claim 15, wherein said at least one humanly perceptual variation of said voice data is selected from the group consisting of: audio distortion, audio choppiness, audio jitter, variations in audio level and combinations thereof.

22. The method according to claim 15, wherein said multimedia information comprises audio signals .

23. The method according to claim 15, wherein said multimedia information comprises video signals .

24. The method according to claim 15, wherein said at least one humanly perceptual variation of said video data is selected from the group consisting of: uneven frame rate resulting in picture jerkiness, audio cut outs or distortion, poor image quality, missing or incomplete video frames , and combinations thereof .

25. The method according to claim 15, wherein said at least one adjustment to said at least one transmission protocol comprises an adjustment selected from the group consisting of: the transmission power level of the source device, the transmission rate and the level of compression.

26. The method according to claim 15, wherein said at least one adjustment comprises changing the compression rate from a first level used with said multimedia information in said signal to a second level after application of said signal metric.

27. A method of operating a network device within a communications network, said method comprising the steps of: transmitting, by said network device within the communications network, a signal containing therein realtime multimedia information, said multimedia information containing therein at least one humanly perceptual variation, said at least one humanly perceptual variation being based upon the quality of the multimedia information being transmitted by said network device; and receiving, from said communications network after said step of transmitting, at least one signal metric based upon the quality of said multimedia information as received at a destination device within said communications network, said signal metric containing at least one adjustment to at least one transmission protocol of said network device, whereby the human perceptual variation of the quality of said signal is adjusted after application of said signal metric.

28. The method according to claim 27, further comprising the step of: adjusting said at least one transmission protocol of said network device using said signal metric.

29. The method according to claim 28, wherein said network device transmits said signal contemporaneous with said step of adjusting and transmits an adjusted signal upon completion of said step of adjusting.

30. The method according to claim 27, wherein said communications network is a code division multiple access wireless network.

31. The method according to claim 27, wherein said communications network is a time division multiple access wireless network.

32. The method according to claim 27, wherein the signal metric is transferred over a dedicated channel. said dedicated channel being distinct from channels of said communications network utilized to transmit signals comprising multimedia information.

33. The method according to claim 27, wherein said multimedia information comprises voice signals.

34. The method according to claim 33, wherein said at least one humanly perceptual variation of said voice data is selected from the group consisting of: audio distortion, audio choppiness, audio jitter, variations in audio level and combinations thereof.

35. The method according to claim 27, wherein said multimedia information comprises audio signals.

36. The method according to claim 27, wherein said multimedia information comprises video signals .

37. The method according to claim 36, wherein said at least one humanly perceptual variation of said video data is selected from the group consisting of : uneven frame rate resulting in picture jerkiness, audio cut outs or distortion, poor image quality, missing or incomplete video frames, and combinations thereof.

38. The method according to claim 27, wherein the humanly perceptual variation of the quality of said signal comprises an adjustment selected from the group consisting of: the transmission power level of the source device, the transmission rate and the level of compression.

39. The method according to claim 38, wherein said at least one adjustment comprises changing the compression rate from a first level used with said multimedia information in said signal to a second level after application of said signal metric.