Source: http://www.google.com/patents/US5745480?dq=5,890,152
Timestamp: 2014-03-15 09:45:15
Document Index: 770739257

Matched Legal Cases: ['art 200', 'art 200', 'art 200', 'art 200', 'art 200', 'art 200', 'art 200', 'art 200', 'art 200', 'art 200']

Patent US5745480 - Multi-rate wireless communications system - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA multi-rate wireless communications system that supports a plurality of distributed user terminals in full-duplex simultaneous communications with a central base station, where each user terminal is provided on demand with one of multiple bit rates at a negotiated QOS is provided. Each user is assigned...http://www.google.com/patents/US5745480?utm_source=gb-gplus-sharePatent US5745480 - Multi-rate wireless communications systemAdvanced Patent SearchPublication numberUS5745480 APublication typeGrantApplication numberUS 08/681,191Publication dateApr 28, 1998Filing dateJul 22, 1996Priority dateApr 3, 1996Fee statusPaidAlso published asCN1215517A, EP0888674A1, EP0888674A4, WO1997037457A1Publication number08681191, 681191, US 5745480 A, US 5745480A, US-A-5745480, US5745480 A, US5745480AInventorsSaman Behtash, Christopher Flores, Adel GhanemOriginal AssigneeAdicom Wireless, Inc.Export CitationBiBTeX, EndNote, RefManPatent Citations (5), Referenced by (180), Classifications (17), Legal Events (22) External Links: USPTO, USPTO Assignment, EspacenetMulti-rate wireless communications systemUS 5745480 AAbstract A multi-rate wireless communications system that supports a plurality of distributed user terminals in full-duplex simultaneous communications with a central base station, where each user terminal is provided on demand with one of multiple bit rates at a negotiated QOS is provided. Each user is assigned a variable bit rate, a variable processing gain, a variable transmit power and a unique fixed rate spreading code, resulting in a constant bandwidth signal received at a relative power level corresponding to the negotiated QOS. This application can be applied to systems including wireless local loop and mobile cellular. By adjusting signal energy and interference energy, variable bit rates and negotiated QOS parameters can be supported. The forward link between base-station and user terminal, and the reverse link between the user terminal and base-station, can correspond to either a Frequency Division Duplexing (FDD) arrangement where the forward and reverse links occupy different carrier frequencies but overlap in time, or a Time Division Duplexing (TDD) arrangement where the forward and reverse links occupy the same carrier frequency but are in non-overlapping time intervals.
What is claimed is: 1. A multi-rate communication system having a base station communicating with a plurality of active user terminals, and a requesting user terminal, each of said user terminals having a transmitter and a receiver, said base station comprising:means for receiving a message from said requesting user terminal to said base station, said requesting user terminal requesting communication using a desired data rate and a desired quality of service QOS parameter; means for determining a suitable data rate, a suitable QOS, and expected received signal power for said requesting user terminal based on said desired data rate and said desired QOS; and means for communicating said suitable data rate, said suitable QOS, and said expected received signal power to said requesting user terminal. 2. The system of claim 1 wherein said means for determining further comprising:means for computing a requested power budget for said requesting user terminal based on said desired data rate and said desired QOS; means for computing a combined power budget for said active user terminals; and means for selecting a suitable data rate as equal to said desired data rate and a suitable QOS as equal to said desired QOS when a sum of said requested power budget and said combined power budget is less than one. 3. The system of claim 2 wherein said means for determining further comprising means for determining an available power budget for said requesting user terminal based on said desired data rate and said desired QOS when a sum of said requested power budget and said combined power budget is greater than one, said suitable data rate and said suitable QOS being related to said available power budget.
4. The system of claim 2 wherein said requesting user terminal communicates with said base station using, a device having, a fixed chip rate (C) and requiring a ratio α of a signal component and an interference component, where said a is determined by said desired QOS, said means for computing said requested power budget (H) calculating said H from: H=&#945;/(PG+&#945;); where PG=C/R and said R is said desired data rate of said requesting user terminal. 5. The system of claim 4 wherein said requesting user terminal further comprises:means for calculating propagation loss in a direction from base-station to said requesting user terminal; means for calculating nominal transmit power based on said propagation loss and said expected signal power communicated by said base station to said requesting user terminal; and means for controlling transmit power based on said nominal transmit power. 6. The system of claim 4 wherein said means for computing a combined power budget computes a sum of a power budget (H.sub.i) of each active user terminal, said power budget H.sub.i being computed from: H.sub.i =&#945;.sub.i /(PG.sub.i +&#945;.sub.i); where PG.sub.i =C/R.sub.i and R.sub.i is a data rate of said ith active user terminal, and α.sub.i is a ratio of a signal component and an interference component of an ith active user terminal. 7. The system of claim 6 wherein said base station further comprises:means for calculating nominal transmit power to each said active user terminal and said requesting terminal such that for each of said active and requesting user terminals the ratio of transmit power to total transmit power exceeds said power budget H.sub.i ; and a variable gain unit for controlling transmit power to each said active user terminal and said requesting terminal based on said calculated nominal transmit power. 8. The system of claim 3 wherein said available power budget (H') is substantially equal to one minus said combined power budget.
9. The system of claim 8 wherein said requesting user terminal communicates with said base station using a device having a fixed chip rate (C) and requiring a ratio α of a signal component to an interference component, said means for computing said suitable data rate (R') calculating said R' from: PG'=&#945;/((1/H')-1), and R'=C/PG'. 10. 10. The system of claim 8 wherein said requesting user terminal communicates with said base station using a device having a fixed chip rate (C) and desired data rate R, said means for computing said suitable QOS (QOS') calculating said QOS' from: PG=C/R, and &#945;'=PG/((1/H')-1), where α' is a ratio of a signal component to an interference component and is related to said QOS'. 11. The system of claim 8 wherein said requesting user terminal communicates with said base station using a device having a fixed chip rate (C), said means for computing said suitable data rate (R') and said suitable QOS (QOS') calculating said R' and said QOS' from: R'=C/PG' and &#945;'=PG'/((1/H')-1); where α' is a ratio of a signal component to an interference component and is related to said QOS', and 1&#8806;PG'&#8806;C/R. 12. The system of claim 8 wherein said available power budget H' is substantially equal to one minus said combined power budget minus δ, where δ represents a fraction of total received power that comes from narrowband interferers.
13. The system of claim 1 wherein said base station communicates with said active and said requesting user terminals using a frequency division duplexing arrangement.
14. The system of claim 1 wherein said base station communicates with said active and said requesting user terminals using a time division duplexing arrangement.
15. The system of claim 1 wherein said means for communicating further comprises means for transmitting over a separate signal channel jointly used by said active and said requesting user terminals.
16. The base station of claim 1 further comprising a plurality of transmitter units, one for each of said user terminals, each of said transmitter units comprising:a framer unit for converting input user bit stream and control bit stream into the closest of one of a plurality of negotiated bit rates that is equal to the product of 2.sup.L and R, where L=1,2, . . . n and R is a minimum bit rate supported by said system; an encoder unit for generating, I and Q symbol streams each at a symbol rate equal to a product of 2.sup.(L-1) and R; a unique code for spreading said I and Q symbol streams to a fixed chip rate I and Q chip stream; a variable gain unit for scaling said I and Q chip streams; a first combiner for combining said scaled I chip stream generated by said plurality of transmitter units of all said user terminals; a second combiner for combining said scaled Q chip stream generated by said plurality of transmitter units of all said user terminals; a quadrature modulator for modulating said combined I and Q chip streams generated by said first and said second combiners; and a variable gain power amplifier for amplifying said modulated signal. 17. The base station of claim 16 wherein said encoder is a general MPSK encoder.
18. The base station of claim 16 wherein said encoder is a differential MPSK encoder.
19. The base station of claim 16 wherein said encoder is a general QAM encoder.
20. The base station of claim 16 wherein separate unique spreading codes are used to generate said I and said Q symbol streams.
21. The base station of claim 1 further comprises a plurality of receiver units, one for each of said user terminals, each of said receiver units comprising:a variable automatic gain controller for amplifying a received signal; a quadrature demodulator for demodulating said amplified signal into an I and a Q chip streams; a unique code for de-spreading, said I and Q chip streams to an I and Q symbol stream; a first integrator for integrating said I symbol stream over a symbol duration; a second integrator for integrating said Q symbol stream over said symbol duration; a decoder unit for generating a received bit stream based on said integrated I and Q symbol streams; and a deframer for generating an output bit stream and a control bit stream based on said received bit stream. 22. The base station of claim 21 wherein said decoder is a general MPSK encoder.
23. The base station of claim 21 wherein said decoder is a differential MPSK encoder.
24. The base station of claim 21 wherein said decoder is a general QAM encoder.
25. The base station of claim 21 wherein separate unique de-spreading codes are used to generate said I and said Q symbol streams.
26. The system of claim 1 wherein each of said transmitters of said plurality of user terminals comprises:a framer unit for converting input user bit stream and control bit stream into the closest of one of a plurality of negotiated bit rates that is equal to the product of 2.sup.L and R, where L=1,2, . . . n and R is a minimum bit rate supported by said system; an encoder unit for generating, I and Q symbol streams each at a symbol rate equal to a product of 2.sup.(L-1) and R; a unique code for spreading said I and Q symbol streams to a fixed chip rate I and Q chip stream; a quadrature modulator for modulating said I and said Q chip streams; and a variable gain power amplifier for amplifying said modulated signal. 27. The user transmitter of claim 26 wherein said encoder is a general MPSK encoder.
28. The user transmitter of claim 26 wherein said encoder is a differential MPSK encoder.
29. The user transmitter of claim 26 wherein said encoder is a general QAM encoder.
30. The user transmitter of claim 26 wherein separate unique spreading codes are used to generate said I and said Q symbol streams.
31. The system of claim 26 wherein each of said receivers of said plurality of user terminals comprises:a variable automatic gain controller for amplifying a received signal; a quadrature demodulator for demodulating said amplified signal into an I and a Q chip streams; a unique code for de-spreading said I and Q chip streams to an I and Q symbol stream; a first integrator for integrating, said I symbol stream over a symbol duration; a second integrator for integrating said Q symbol stream over said symbol duration; a decoder unit for generating a received bit stream based on said integrated I and Q symbol streams; and a deframer for generating an output bit stream and a control bit stream based on said received bit stream. 32. The user receiver of claim 31 wherein said decoder is a general MPSK encoder.
33. The user receiver of claim 31 wherein said decoder is a differential MPSK encoder.
34. The user receiver of claim 31 wherein said decoder is a general QAM encoder.
35. The user receiver of claim 31 wherein said unique de-spreading codes are used to generate said I and said Q symbol streams.
36. A method for a multi-rate wireless communication system having a base station and a plurality of active user terminals to allocate a data rate for a requesting user terminal, said requesting user terminal requesting a desired data rate (R) at a desired quality of service (QOS), said method comprising the steps of:computing a requested power budget for said requesting user terminal based on said desired data rate and said desired QOS; computing a combined power budget for said active user terminals; and granting, by said base station, said desired data rate and said desired QOS when a sum of said requested power budget and said combined power budget is less then one. 37. The method of claim 36 further comprising the steps of:computing an available power budget for said requesting user terminal; determining a suitable data rate and suitable QOS when a sum of said requested power budget and said combined power budget exceeds one, said suitable data rate and said suitable QOS being related to said available power budget; and sending said suitable data rate and suitable QOS to said requesting user terminal. 38. The method of claim 37 further comprising the step of determining a signal component of said requesting user terminal such that it operates within said available power budget.
39. The method of claim 36 wherein said wireless communication system has a fixed chip rate (C) and said requesting user terminal requires a ratio α of a signal component to an interference component, said requested power budget (H) being computed from: H=&#945;/(PG+&#945;); where PG=C/R and R is said desired data rate of said requesting terminal. 40. The method of claim 39 wherein said combined power budget is a sum of a power budget (H.sub.i) of each active user terminal, said power budget H.sub.i being, computed from: H.sub.i =&#945;.sub.i /(PG.sub.i +&#945;.sub.i); where PG.sub.i =C/R.sub.i, and where α.sub.i is a ratio of a signal component to an interference component of an ith active user terminal and R.sub.i is a bit rate of said ith active user terminal. 41. The method of claim 37 wherein said available power budget (H') is substantially equal to one minus said combined power budget.
42. The method of claim 41 wherein said wireless communication system has a fixed chip rate (C) and said requesting user terminal requires a ratio α of a signal component to an interference component, said suitable data rate (R') is computed from: PG'=&#945;/(1/H'-1), and R'=C/PG'. 43. The method of claim 38 wherein said wireless communication system has a fixed chip rate (C) and said available power budget (H') is substantially equal to one minus said combined power budget, said signal component (S') of said requesting user terminal being computed from: S'=&#945;'I; &#945;'=PG/(1/H'-1) and PG=C/R; where I is an interference component of said requesting user terminal, which in turn is calculated as I=(sum of all S.sub.j)/PG, where S.sub.j is received near signal power from jth user terminal measured by said base station. 44. The method of claim 36 further comprising a step of modulating signals of said base station and said active and requesting user terminals.
45. The method of claim 37 wherein said sending step further comprises a step of transmitting over a separate signal channel jointly used by said active and said requesting user terminals.
46. The method of claim 36 further comprising the steps, executed by said base station, of:converting a combined user bit stream and a control bit stream to one of a plurality of bit rates that is equal to a product of 2.sup.L and R, where L=1,2, . . . n and R is a minimum bit rate supported by the system; encoding, said converted bit stream into I and Q signals; spreading said I and Q signals by a unique spreading code at a fixed chip rate to generate I and Q fixed rate chip streams; scaling said I and Q fixed rate chip streams for each of said active user terminals to achieve the negotiated QOS; summing said scaled I, Q fixed rate chip streams generated by transmitters of said active user terminals; modulating said summed I and Q fixed rate chip streams to a reverse link frequency; and amplifying said modulated signal using a variable gain amplifier. 47. The method of claim 46 wherein separate spreading codes are used to generate said I and said Q symbol streams.
48. The method of claim 46 further comprising the steps, executed by each of a plurality of receiver units in said base station, of:amplifying a received signal; demodulating said amplified signal into an I and a Q chip stream; de-spreading said I and said Q chip streams into an I and an Q symbol stream using a unique code; integrating said I symbol stream over a symbol duration; integrating said Q symbol stream over said symbol duration; decoding a received bit stream based on said integrated I and Q symbol streams; and generating an output bit stream and a control bit stream. 49. The method of claim 48 wherein separate de-spreading codes are used to generate said I and said Q symbol streams.
50. The method of claim 36 further comprising the steps, executed by each of said active user terminals, of:converting a combined user bit stream and control bit stream to one of a plurality of bit rates that is equal to a product of 2.sup.L and R, where L=1,2, . . . n and R is a minimum bit rate supported by the system; encoding said combined bit stream into I and Q signals; spreading said I and Q signals by a unique spreading code at a fixed chip rate to generate I and Q fixed rate chip streams; modulating said I and Q fixed rate chip streams to a forward link frequency; and amplifying said modulated signal at a level commanded by said base station. 51. The method of claim 50 wherein separate spreading codes are used to generate said I and said Q symbol streams.
52. The method of claim 50 further comprising the steps of:amplifying a received signal; demodulating said amplified signal into an I and a Q chip stream; de-spreading said I and said Q chip streams into an I and an Q symbol stream using a unique code; integrating said I symbol stream over a symbol duration; integrating said Q symbol stream over said symbol duration; decoding a received bit stream based on said integrated I and Q symbol streams; and generating an output bit stream and a control bit stream. 53. The method of claim 52 wherein separate de-spreading codes are used to generate said I and said Q symbol streams.
CROSS-REFERENCE TO RELATED PROVISIONAL APPLICATION This application claims the benefit of U.S. provisional application Ser. No. 60/014766, filed on Apr. 3, 1996.
FIELD OF THE INVENTION The present invention relates to wireless communications, and more particularly, to methods and systems that simultaneously support a plurality of distributed user terminals connected to a central base station, each user terminal provided on demand one of multiple bit rates at a negotiated Quality of Service (QOS).
BACKGROUND OF THE INVENTION Wireless networks today are mainly designed for voice communication in the local loop or mobile cellular environments. This application is adequately handled by fixed bit rate services. On the other hand, wire-line networks have evolved to a point where they can simultaneously support multiple services like voice, data, image, and video, each with different bit rate requirements. An example of such a system is asynchronous transfer mode (ATM). It is found that this flexibility increases efficiency and reduces costs of a telecommunication system. Because wireless telecommunications systems typically follow the trends of wire-line systems, there will soon be a demand for wireless networks to support the same services. Further these services must be supported on a dynamic bandwidth-on-demand basis at varying service-related and/or user-requested Quality of Service (QOS) parameters (e.g., Bit Error Rate (BER)). This is because different bandwidths are required to support different services, For example, voice may require only 32 Kilo-bit per second (Kbps) while data may require 128 Kbps and video may require 1.5 Mbps. Similarly, different services require different QOS parameters (such as BER). For example, voice can tolerate a BER of 10.sup.-3 for a 32 Kbps service whereas data may require BER=10.sup.-7. Finally these requirements must be satisfied in a cost effective manner both in the efficient use of the precious radio spectrum and the reduction of equipment costs.
Currently, there is no Frequency Division Multiple Access (FDMA) and Time Division Multiple Access (TDMA) system which can support bandwidth-on-demand and variable QOS. In existing art, some FDMA, TDMA and Code Division Multiple Access (CDMA) systems achieve multiple bit rates by aggregating individual channels. An example of such a CDMA system is disclosed in U.S. Pat. No. 5,442,625 entitled "Code Division Multiple Access System Providing Variable Data Rate Access To A User." The system in the '625 patent supports a channel of rate M channels each of rate R. This is an expensive solution as it requires baseband hardware for simultaneous support of M channels, which is wasteful at the user terminals, especially if M is large or the high bandwidth is only required occasionally.
SUMMARY OF THE INVENTION The present invention is a flexible multi-rate wireless communications system that supports a plurality of distributed user terminals in full-duplex simultaneous communications with a central base station, where each user terminal is provided on demand with one of multiple bit rates at a negotiated QOS. One embodiment of this system is based on CDMA with each user assigned a variable bit rate, a variable processing gain, a variable transmit power, and a unique fixed rate spreading code, resulting in a constant bandwidth signal received at a relative power level corresponding to the negotiated QOS. The above embodiment can be implemented in Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD) configurations. The applications for this system include wireless local loop, mobile cellular, and wireless multimedia access systems.
The BER QOS parameter for an individual user terminal in a CDMA system depends on the received Signal-to-Interference ratio (S/I). The signal energy S is determined by two factors: (i) the received user signal energy per chip, and (ii) the combination (determined by the auto-correlation properties of the spreading codes) of the user energy per chip over the number of chips per user bit duration. The interference energy I is determined by the sum of interference energy for all the other users. The interference energy from each of the other users is determined by two factors: (i) the received signal energy per chip of the other user, and (ii) the combination (determined by the cross-correlation properties of the spreading codes) of the energy per chip of the other user over the number of chips per bit duration, By adjusting the two factors in signal energy and the two factors in the interference energy (i.e., a total of four factors), variable bit rates and negotiated QOS parameters can be supported. Further, by keeping the channel bandwidth fixed for all bit rates the equipment costs, particularly the RF stage where the components (e.g., filters) have fixed bandwidths, will be reduced.
Further, the forward link (i.e., from base-station to user terminal) and the reverse link (ire., from the user terminal to base-station) can correspond to either a FDD arrangement where the forward and reverse links occupy different carrier frequencies but overlap in time or a TDD arrangement where the forward and reverse links occupy the same carrier frequency but are in non-overlapping time intervals.
It should be noted that in the current invention, the channels are resized based on the factors described above. This is different from the aggregation method used in the prior art.
DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a novel wireless communication system and related methods. The following description is presented to enable any person skilled in the art to make and use the invention. Description of specific applications is provided only as examples. Various modifications to the preferred embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.
FIG. 1 is a schematic diagram of a wireless communications system 100 of the present invention. It comprises a base station 102 and a plurality of user terminals, such as stations 104-106. The terminals connect to user applications (e.g. voice, data, video) while the base-station connects to a telecommunications network. The base station and individual user terminals negotiate bit rates and QOS parameters using, the systems and methods disclosed below.
FIG. 2 is a schematic diagram of a transmitter portion 120 of a user terminal in one of the user terminals of FIG. 1. Transmitter portion 120 contains a coding and symbol mapping unit 124 which accepts variable bit rate data from a signal path 122 and generates symbols of variable rate. The symbols are coupled to a multiplier 126 which multiplies the symbols with a pseudo-noise (PN) sequence chip stream generated by a PN sequence generator 130. As a result, a PN modulated symbol stream is generated. This stream is coupled to a digital gain control unit 134. The gain of unit 134 is managed by a gain control logic 136. The output of unit 134 is coupled to a digital-to-analog (DIA) converter 138 which converts the digital data into analog form. The analog, signal is coupled to an analog gain control unit 140 which changes the amplitude of the analog signal. The gain of unit 140 is also managed by gain control logic 136. In the present invention, gain control logic 136 could be a digital or an analog device, or a combination of the two. The output of unit 140 is coupled to a radio frequency processing unit 144 which modulates the incoming analogy signal into a high frequency signal suitable for radio transmission using an antenna 146. Note that both analog, gain control unit 140 and digital gain control unit 134 serve the same function (i.e., to control the gain of signals) although they operate in the analog, and digital domains, respectively. The (optional) use of two gain control units allow maximum gain control range to be achieved or the gain to be controlled more finely (i.e. analog for coarse gain control, digital for fine gain control).
As explained in more detail below, the user terminal negotiates with the base station a bit rate and an allowable transmission power based on user's requested service and desired QOS. This negotiation may occur at connection setup or during a connection. Gain control logic 136 adjusts the gains of digital gain control unit 134 and analog gain control unit 140 in accordance with the negotiated value.
FIG. 3 is a drawing showing, a schematic diagram of a portion of base station 102 which negotiates with gain control logic 136 of the user terminal and determines the appropriate bit rate and transmission power of that user terminal. Base station 102 comprises a plurality of receivers, such as receivers 172.sub.a, 172.sub.b, . . . , and 172.sub.n, each receives wireless signal generated by all the user terminals. Based on the received wireless signal, each receiver generates a signal component. For example, receivers 172.sub.a, 172.sub.b, and 172.sub.n generate signal components S.sub.a, S.sub.b, S.sub.n, respectively. These components are coupled to a system controller 176.
System controller 176 receives service requests from one of the user terminals via a communication path 178. It determines (using an algorithm described below) the appropriate bit rate and transmission power that can be supported based on information in the signal components received from receivers 172.sub.a, 172.sub.b, . . . and 172.sub.n. The result is modulated by a radio frequency processing unit 180 and then transmitted to the requesting user terminal via an antenna 182. The requesting user terminal may accept or reject the result. The requesting user terminal may later send another service request (i.e., re-negotiate) if the result is being rejected at the current negotiation.
FIG. 4 is a flow chart of an algorithm 200 used by system controller 176 for determining a data rate for a user terminal. System controller 176 receives a service request from a user terminal (such as terminal 104) specifying a desired data rate R and a desired BER (step 204). It is known that there is a direct relationship between BER and the ratio of signal component (S) and interference component (I). An example is BER=0.5 exp (-S/I) for a DBPSK modulation scheme. Other examples can be found in Proakis, J. H., "Digital Communications", 2nd Edition, McGraw Hill, 1989. In this specification, the ratio S/I is assigned a symbol a so as to facilitate the discussion that follows. The symbol "I" denotes the interference from all the other terminals. This ratio can be determined once the desired BER is known.
Upon receiving the above request, system controller 176 computes the required power budget (step 208). It first computes a processing gain (PG), which is defined as:
PG=chip rate/R.
In the present invention, the chip rate is fixed. One of the advantages of using a fixed chip rate is that the costs of equipments are reduced compared to the case where the chip rate could be varied. Another advantage is that a fixed chip rate corresponds to a fixed RF channel bandwidth. This makes frequency planning, and allocation considerably simpler because all cells and all channels in each cell occupy the same bandwidth. Thus, the PG is inversely proportional to the data rate R.
System controller 176 then computes a power budget H using the following formula:
H=&#945;/(PG+&#945;).
The power budget is simply the minimum fraction of the received power allocated to each user. Note that the power budget for all the users must add to less than or equal to one, assuming that there are no narrowband interferences. For example, for a set of three users, the power budgets may be 0.5, 0.3, and 0.1. In case of narrowband interferences, the total power budget is less than or equal to 1-δ where δ represents the fraction of the received power that belongs to the interferers.
In step 210, system controller 176 then compares H with the quantity (1-Σ H.sub.i). The quantity H.sub.i is the power budget for user i to achieve its desired data rate and BER. The summation is performed over all active user terminals (i.e., excluding the requesting terminal). The comparison checks if the requested power budget is less than the available power budget. If the quantity H is less than (1-Σ H.sub.i), flow chart 200 branches to step 214, in which case the requested data rate is granted. Flow chart 200 proceeds to set up the connection between the requesting user terminal and base station 102 (step 218). If the quantity H is greater than (1-Σ H.sub.i), flow chart 200 branches to step 220, in which case system controller 176 computes an available power budget H' using the formula:
H'=1-&#931; H.sub.i.
The system controller may negotiate the data rate, BER, or both. For example, assuming the system controller negotiates only the data rate, then in step 222, system controller 176 determines a maximum data rate (R') for the requested α (i.e. BER) using the formula:
PG'=&#945;(1/H'-1); and
R'=chip rate/PG'.
Similarly the system controller can determine α' for the requested R or determine both α' and R' that satisfy the above equations. The formula for α is given by
&#945;'=PG/(1/H'-1)
In step 224, the base station sends a reply to the service request previously sent by the requesting user terminal in step 204. The reply indicates that R' is an offered data rate. The user terminal determines if the offered rate R' is acceptable (step 228). If the offer is accepted, flow chart branches to step 218 (i.e. set up connection). If the offer is not accepted, flow chart 200 terminates (step 230). When the user terminal wishes to re-negotiate with the base station, it could initiate the whole negotiation process again at that time.
As pointed out above, both the data rate and the transmission power are variable. Thus, in step 218, base station 102 informs the requesting user terminal the expected received user signal power S.sub.i. The requesting user terminal can calculate the transmission power by estimating the propagation loss and adding, this to the expected received user signal power S.sub.i. The estimation process is described in more detail below.
In the following disclosure, detailed implementations of the present invention in a time division duplexing, and a frequency division duplexing are disclosed. The reverse link (from the user terminals to the base station) and the forward link (from the base station to the individual user terminals) are separately discussed.
Reverse Link from the User Terminal to the Base Station:
In the reverse link, each user terminal wishing, to establish a connection transmits a Connection Request message specifying, the requested bit rate, which is selected from a set of supported bit rates, and a particular QOS parameter, such as BER. This operation corresponds to step 204 of flow chart 200 (see FIG. 4). The message is transmitted over a signaling channel. In the specific embodiment this channel is a Common Signaling Channel (CSC). The CSC is a separate channel that is shared by all the user terminals for service negotiation with the base station. In a TDD system the CSC is a separate time slot or frame while in a FDD system the CSC is a separate frequency carrier. If the message transmission is unsuccessful (e.g., there is a, collision with other user terminal transmissions), the base-station does not receive the message and does not respond. After a variable time-out period the user terminal re-transmits the request message. Note that other re-transmit schemes are possible.
If the message transmission is successful, the base-station responds with a Connection Response message that includes (a) the bit-rate at the particular BER that can be granted by the base-station to the user terminal for the existing traffic conditions and (b) the expected user signal power at the base station. Upon acceptance by the requesting user terminal, a connection is set up. This corresponds to step 218 of flow chart 200. The base-station determines the expected user signal power at the base station (which depends on the requested bit rate and BER) and the interference from other simultaneous users, as explained in flow chart 200.
The difference between the base station transmit power (which is a system parameter) and the received power at the user terminal is the propagation loss in the direction from base-station to user terminal. Assuming reciprocity, the propagation loss is the same in the direction from the user terminal to the base-station. Hence, the user terminal adds this propagation loss to the expected user power discussed above to arrive at the nominal transmit power. The user terminal either (i) accepts the connection by transmitting a Connection Accept message or (ii) rejects the connection (if the maximum bit-rate granted by the base-station is less than the user terminal requirements) by transmitting a different Connection Reject message. The user terminal may attempt the bit rate negotiation again at a later time.
For each user terminal that successfully negotiates a connection with the base-station, the source symbol stream is multiplied by its unique spreading code at a system-defined fixed chip rate resulting in a wideband signal at the fixed chip rate. The unique spreading code for a user terminal is any Pseudo-Noise (PN) code that generates near random cross-correlation properties over any out-of-phase sub-sequences. The processing gain for this user terminal is the ratio of the chip rate to the negotiated user bit rate. The user wideband signal is then modulated to the carrier frequency and transmitted at the nominal power calculated above. Now the user terminal transmit power level has to be continually adjusted due to changes in the received signal power (due to fading and/or mobility) and interference power (due to other user service requests) at the base station. These adjustments are based on power control commands sent by the base station to the user terminal. Based on the power control commands the user terminal increases or decreases the transmitted power by adjusting the control voltage of the power amplifier.
At the base station, the sum of all the received user signals is first demodulated from the carrier frequency to baseband. For each user signal, a receiver in the base station multiplies the wideband signal with the user-specific unique spreading code, defined above as a PN sequence, and integrates the signal energy over the symbol duration. The resulting signal consists of a signal (S) component and an interference (I) component. The S component constitutes the signal energy received over the user bit duration from coherently combining the energy in all the chips per user bit. The I component constitutes the sum of the energy received from all the other users, each obtained by randomly combining (due to the random cross-correlation properties of the PN sequence) the energies in all the chips per user bit. The S components are estimated by the measurement module in each receiver and the results are communicated to the system controller. For each receiver the system controller calculates the S/I ratio and compares it against the required S/I ratio to achieve the negotiated the BER for the corresponding user terminal. The relation between the required S/I and the BER depends on the modulation scheme (i.e., BPSK, DQPSK etc.).
The following, analysis is the basis for the flow chart 200. For an individual user the Signal-to-Interference (S/I) ratio is given by S/I=S/Σ I.sub.j =(PG) (S) /Σ S.sub.j where PG is the processing gain for the user, S.sub.i is the signal energy for the other users j and the summation Σ is over all the other users. For the desired BER, S/I&gt;α where α, are defined in the flow chart 200, is the Signal-to Interference ratio corresponding to the desired BER. Thus, PG. S/Σ S.sub.j &gt;α. If S.sub.T= S+Σ S.sub.j represents the total received signal energy, then the above requirement can be re-written as Condition (1):
S/S.sub.T &amp;gt;&#945;/(PG+&#945;).                           (1)
Note that α/(PG+α) was defined as the power budget H in the flow chart 200. In other words, the fraction of the received power from a user S/S.sub.T must be grater than the power budget H for that user. Note also that the power budget H is directly determined by the user requested bit-rate and BER.
In case of no narrowband interferers, as the summation of S/S.sub.T over all users equals 1, the summation of H over all users must be less than or equal to 1 from condition (1). Hence we have condition (2):
&#931; H.sub.i &amp;lt;=1                                        (2)
where H.sub.i is the power budget for user i.
In case of narrowband interferers, the summation of S/S.sub.T over all users equals 1-δ, where δ represents the fraction of the total received power that comes from narrowband interferers. Obviously in this case (2) becomes Σ H.sub.i &lt;=1-δ, thereby reducing the capacity of the system.
Link from the Base Station to the Individual User Terminals:
In the forward link, the base station transmitter applies a variable gain to each individual user signal before combining such that the (1) is satisfied. As the propagation environment in the forward link affects all signals equally, the ratio of the signals will not change even though the absolute signal levels decrease with increasing distance from the base station. Hence the signals received at an individual user terminal receiver will have the same S/S.sub.T ratio as sent by the base station and hence the negotiated BER value.
In order to further illustrate the present invention, an example is given below. Consider a system with two user terminals, UT.sub.1 and UT.sub.2, co-located with each other (to exclude propagation variations) with peak transmit powers of 1000 mW each and a single base station BS. UT.sub.1 requests a 32 Kbps bit rate at a 10.sup.-3 BER for voice service and UT.sub.2 requests a 128 Kbps bit rate at 10.sup.-5 BER for high-speed Internet access. Assume a system fixed chip rate of 4096 Kilo-chips per second (Kcps).
In the reverse link, the UT.sup.1 bit stream is multiplied by a PN code at rate of 4096 Kcps (this corresponds to a processing gain of 128 (i.e., 4096/32)) and the UT.sub.2 bit stream is multiplied by a PN code again at rate 4096 Kcps (this corresponds to a processing gain of 32 (i.e., 4096/128)). If DQPSK modulation is used, the required S/I ratio at the BS receiver for UT.sub.1 and UT.sub.2 for the requested BERs are 9 dB and 12 dB, respectively. (See, for example, FIG. 4.2.20 of Proakis, J. H., "Digital Communications", 2nd Edition, McGraw Hill, 1989). Now the UT.sub.1 received signal has a processing gain of 21 dB (i.e., 10log128) and the UT.sub.2 signal has a processing gain of 15 dB (i.e., 10log32). This corresponds to power budgets H.sub.1 =0.06 and H.sub.2 =0.33, respectively. Note that this satisfies (2). The UT.sup.1 and UT.sup.1 receive power levels are adjusted in the same ratio as the power budgets H.sub.1 and H.sub.2. Since the propagation losses are identical for both UT.sub.1 and UT.sub.2 (by assumption), the transmit power levels are also in the same ratio as H.sub.1 and H.sub.2. Hence, for example, UT.sub.1 can have transmit power 60 mW and UT.sub.2 can have transmit power 330 mW. The corresponding values of S/S.sub.T are 60/390 (=0.15) and 330/390 (=0.85), which satisfy (1).
In the forward link, the same spreading codes are used for UT.sub.1 and UT.sub.2 at the BS transmitter. The power budgets are again for H.sub.1 =0.06 and H.sub.2 =0.33 at the UT.sub.1 and UT.sub.2 receivers. This again satisfies (2). If the two signals are combined at the BS in the same ratio as the power budgets H.sub.1 and H.sub.2 they are received at each of the user terminals UT.sup.1 and UT.sup.2 in the same ratio. For example, the BS can transmit at 390 mW with 60 mW in the signal to UT.sup.1 and 330) mW in the signal to UT.sub.2. The corresponding values of S/S.sub.T are 60/390 (=0.15) and 330/390 (=0.85), which again satisfy (1).
An exemplary embodiment using CDMA is described. CDMA has certain inherent advantages over FDNM and TDMA in wide-area wireless communications networks (e.g., wireless loop and mobile cellular): (i) multipath propagation provides a diversity gain for CDMA RAKE receivers but instead causes intersymbol interference and the need for complex equalizers for TDMA systems, (ii) in CDMA systems no frequency planning is required that is common for FDMA and TDMA systems, and (iii) the interference-limited nature of CDMA allows "soft" capacity limits as compared with the "hard" capacity limits of TDMA and FDMA systems.
An apparatus 300 which can be used to implement an embodiment of the present invention is described herein. FIG. 5 shows a plurality of User Terminals, such as user terminal 1 (designated by numeral 302), . . . , and user terminal N (designated by numeral 304). Each user terminal contains a transmitter unit and a receiver unit. The transmitter and receiver units in all the user terminals are substantially identical. In FIG. 5, user terminal 302 contains a transmitter unit 308 and a receiver unit 310. Transmitter unit 308 consists of a Framer 312 which multiplexes user terminal source bit stream and control bit stream (containing control information and signaling messages generated by a Controller 314) into a single bit stream with rate selected from one of the multiple bit rates 2.sup.L supported by the system. Framer 312 is connected to a DQPSK encoder 316 that generates the In-Phase (I) signal and the Quadrature-Phase (Q) signal, each at a symbol rate 2.sup.(L-1) be replaced by any other MPSK or differential MPSK encoder well-known in the existing art, including BPSK, DBPSK, and QPSK. DQPSK encoder 316 may also be replaced by any other linear modulation scheme like QAM. Note that non-linear modulation schemes like FSK are not suitable for this system.
The I and Q signals generated by encoder 316 are spread by a PN code generator 318 having, a PN code PN.sub.1 operating at a chip rate C. The processing gain G defined as the chip rate divided by the symbol rate or C/(2.sup.(L-1) longer than the maximum processing gain C/R to allow for random cross correlation properties over any out-of-phase sub-sequences. The spread I and Q outputs of transmitter 308 are used to modulate an in-phase carrier (i.e., cosw.sub.u t) and the quadrature-phase carrier (i.e., sinw.sub.u t), respectively. In certain cases an optional half-chip delay unit is included to provide better spectral shaping. The output of the modulators are radio frequency signals that are combined, amplified via a variable gain amplifier 320 of value PA.sub.1, and transmitted via an antenna 328 to the base station. The amplifier values (e.g., PA.sub.1 for user terminal 302, . . . , and PA.sub.n for user terminal 304) are set by commands from the base station. As explained below, the power control commands are decoded by Controller 314 after receipt from a Deframer 334 of receiver 310. Accordingly, Controller 314 adjusts the values of the variable gains in the RF Control block 336, which generates the control signal for the PA.sub.1 gain value.
The base station transmits in this first embodiment on a different carrier frequency w.sub.d in accordance with an FDD arrangement. At the receiver side of user terminal 302, after the Automatic Gain Control circuit 338 (AGC.sub.1), the received signal is demodulated in quadrature by multiplying by the sine and cosine signals to produce the baseband I and Q signals. The I and Q signals are then fed to receiver unit 310 and are de-spread by a PN code generator 340 having the same PN code PN.sub.1 as that generated by generator 318. As a result, it is operating at the chip rate C. The de-spread I and Q signals are integrated over each symbol duration (by integrators 361 and 362, respectively) and are fed to a DQPSK decoder 344 for conversion into a binary bit stream of rate 2.sup.L conversion back to the user terminal source bit stream and the control bit stream containing control information (e.g., power control commands) and signaling messages which are sent to Controller 314. A Measurement Module 346 estimates the signal energy S.sub.1 from the de-spread I and Q signals and the DQPSK decoder output.
Controller 314 in User Terminal 302 implements all the control and signaling functions. The control functions include the configuration of the transmitter and receiver parameters, the initialization of the PN code generators, control of the oscillator frequencies w.sub.u and w.sub.d, the gain control of the power amplifier and the measurement of the user signal strength S.sub.1. Controller 314 also implements the signaling protocol, writing, messages (e.g. Connect Request) to Framer 312 and reading messages (e.g., Connect Response) from De-framer 334.
RF Control block 336 generates the control signals based on control values specified by Controller 314.
FIG. 6 shows the transmitter and receiver units at a base station 400 which controls the User Terminals 302, . . . , 304. It contains a plurality of transmitter units 402, 404, . . . and 406. Each of these transmitter units are substantially the same as the transmitter unit of the user terminal in FIG. 5. The I and Q outputs of transmitter units 402, 404, . . . and 406 are scaled by the units with variable gain units 412, 414, . . . and 416, respectively, having gains VG.sub.1, VG.sub.2, . . . , VG.sub.n, respectively, before being combined and quadrature modulated to the carrier frequency w.sub.d. The gain VG.sub.1, . . . , VG.sub.n values are calculated to provide the proper received power budgets for each of the user terminal signals as per the conditions (1) and (2) derived above. These VG.sub.1, . . . , VG.sub.n gains are implemented in the digital domain as simple multiplications and are set by a system Controller module 418. Controller module 418 is substantially the same as system controller 176 of FIG. 3.
Base station 400 contains a plurality of receiver units 432, 434, . . . and 436. Each of these receiver units is substantially the same as the receiver unit of the user terminal in FIG. 5. In addition to providing the users with data streams, they also provide the corresponding control bit stream and signal strengths S.sub.1, . . . ,S.sub.n to Controller 418.
FIGS. 7 and 8 show a second embodiment of this invention corresponding to a TDD arrangement where the same carrier frequency is used for both the forward and reverse links (i.e., w.sub.u =w.sub.d). Correspondingly, the chip rate is 2 unchanged for both the User Terminals and the base station. A Transmit/Receive ("T/R") switch connects either the transmitter unit or the receiver unit to the antenna. A block diagram of user terminals 500 is shown in FIG. 7 and a block diagram of base station 600 is shown in FIG. 8. Components in FIGS. 7 and 8 that are the same as components in FIGS. 5 and 6 are assigned the same reference numerals.
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic diagram of a wireless system of the present invention,
FIG. 2 is a block diagram of a transmitter portion of a user terminal of the present invention.
FIG. 3 is a schematic diagram of a portion of the base station of the present invention for determining a data rate and negotiating with a user terminal of the present invention.
FIG. 4 is a flow chart of an algorithm used in the base station of the present invention for determining a data rate for a user terminal of the present invention.
FIG. 5 shows a block diagram of the transmitter and receiver of a first embodiment of a user terminal with variable bit rate and negotiated QOS parameters in accordance with the present invention.
FIG. 6 shows a block diagram of the transmitter and receiver of the first embodiment of a base station supporting multiple user terminals with variable bit rates and negotiated QOS parameters.
FIG. 7 shows a block diagram of the transmitter and receiver of a second embodiment of a user terminal with variable bit rate and negotiated QOS parameters in accordance with the present invention.
FIG. 8 shows a block diagram of the transmitter and receiver of a second embodiment of a base station supporting multiple user terminals with variable bit rates and negotiated QOS parameters.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS5396516 *Feb 22, 1993Mar 7, 1995Qualcomm IncorporatedMethod and system for the dynamic modification of control paremeters in a transmitter power control systemUS5442625 *May 13, 1994Aug 15, 1995At&T Ipm CorpCode division multiple access system providing variable data rate access to a userUS5581575 *Oct 5, 1995Dec 3, 1996Qualcomm IncorporatedMethod and apparatus for transmission of variable rate digital dataUS5603096 *Jul 11, 1994Feb 11, 1997Qualcomm IncorporatedReverse link, closed loop power control in a code division multiple access systemUS5604730 *Jul 25, 1994Feb 18, 1997Qualcomm IncorporatedRemote transmitter power control in a contention based multiple access system* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS5852603 *Feb 26, 1997Dec 22, 1998Nokia Mobile Phones LimitedTransceiver with switchable frequency band and bandwidthUS5912644 *Aug 5, 1997Jun 15, 1999Wang; James J. M.Spread spectrum position determination, ranging and communication systemUS5991286 *Feb 20, 1997Nov 23, 1999Telefonaktiebolaget L M Ericsson (Publ)Support of multiple modulation levels for a cellular packet control channelUS5999563 *Oct 31, 1996Dec 7, 1999Texas Instruments IncorporatedRate negotiation for variable-rate digital subscriber line signalingUS6041233 *Sep 12, 1997Mar 21, 2000Hughes Electronics CorporationMethod and system for providing global variable data rate connectivity in a satellite-based communications networkUS6046991 *Apr 9, 1997Apr 4, 2000Aloha Networks, Inc.TDM variable broadcast energy transmitterUS6061339 *Dec 10, 1997May 9, 2000L-3 Communications CorporationFixed wireless loop system having adaptive system capacity based on estimated signal to noise ratioUS6169733 *May 12, 1997Jan 2, 2001Northern Telecom LimitedMultiple mode capable radio receiver deviceUS6201971 *Jul 16, 1998Mar 13, 2001Nokia Mobile Phones Ltd.Apparatus, and associated method for controlling service degradation performance of communications in a radio communication systemUS6278693 *Mar 24, 1997Aug 21, 2001International Business Machines Corp.Communications systems with quality of service parametersUS6304593 *Oct 6, 1998Oct 16, 2001California Institute Of TechnologyAdaptive modulation scheme with simultaneous voice and data transmissionUS6370158 *Nov 14, 1997Apr 9, 2002Wireless Facilities, Inc.Wireless T/E Transceiver frame signaling subcontrollerUS6370203 *Nov 4, 1998Apr 9, 2002Ericsson Inc.Power control for wireless communications systemUS6381445 *Aug 28, 2000Apr 30, 2002Matsushita Electric Industrial Co., Ltd.Radio communication device and method of controlling transmission rateUS6411819 *Nov 19, 1998Jun 25, 2002Scoreboard, Inc.Method of modeling a neighbor list for a mobile unit in a CDMA cellular telephone systemUS6434380Dec 13, 1999Aug 13, 2002Telefonaktiebolaget Lm Ericsson (Publ)Dynamic negotiation of resources for user equipment in wireless communications systemUS6445916 *Jan 7, 1999Sep 3, 2002Lucent Technologies Inc.Wireless system and method for evaluating quality of serviceUS6487394Aug 28, 2000Nov 26, 2002Matsushita Electric Industrial Co., Ltd.Radio communication device and method of controlling transmission rateUS6505035Jan 23, 2002Jan 7, 2003Matsushita Electric Industrial Co., Ltd.Radio communication apparatus and transmission rate control methodUS6522628 *Feb 25, 2000Feb 18, 2003Cisco Technology, Inc.Method and system for managing transmission resources in a wireless communication networkUS6556824 *Oct 28, 1999Apr 29, 2003Nokia CorporationApparatus, and associated method for controlling service degradation performance of communication in a radio communication systemUS6567474Mar 2, 1999May 20, 2003Phonex CorporationDigital wireless phone/modem jack capable of communications over the power lines using differential binary phase shift keying (DBPSK)US6594251 *Jul 6, 1999Jul 15, 2003Cisco Technology Inc.Polling for transmission power controlUS6636500 *Jul 27, 1999Oct 21, 2003Lucent Technologies Inc.Medium allocation methodUS6657980Apr 12, 2001Dec 2, 2003Qualcomm IncorporatedMethod and apparatus for scheduling packet data transmissions in a wireless communication systemUS6697378Oct 16, 1998Feb 24, 2004Cisco Technology, Inc.Method and apparatus for class based transmission control of data connections based on real-time external feedback estimates obtained using messaging from a wireless networkUS6760312Nov 30, 1999Jul 6, 2004Lucent Technologies Inc.Quality of service on demandUS6766365 *May 12, 1999Jul 20, 2004Honeywell International Inc.Ripple scheduling for end-to-end global resource managementUS6842434 *Dec 31, 1998Jan 11, 2005Qwest Communications International Inc.Method and system for sharing CDMA data traffic channel among multiple usersUS6847629Nov 30, 2000Jan 25, 2005Qualcomm IncorporatedMethod and apparatus for scheduling packet data transmissions in a wireless communication systemUS6859446Sep 11, 2000Feb 22, 2005Lucent Technologies Inc.Integrating power-controlled and rate-controlled transmissions on a same frequency carrierUS6865185Feb 25, 2000Mar 8, 2005Cisco Technology, Inc.Method and system for queuing traffic in a wireless communications networkUS6904286Jul 18, 2001Jun 7, 2005Cisco Technology, Inc.Method and system of integrated rate control for a traffic flow across wireline and wireless networksUS6907243 *Jun 9, 2000Jun 14, 2005Cisco Technology, Inc.Method and system for dynamic soft handoff resource allocation in a wireless networkUS6961316 *Jan 16, 2001Nov 1, 2005Ddi CorporationMobile communication system having adaptively assigned packet rateUS6963551 *Apr 19, 1999Nov 8, 2005Ntt Mobile Communications Network, Inc.Signal transmission method and base station in mobile communicationUS6996127 *May 28, 2003Feb 7, 2006Qualcomm IncorporatedMethod and apparatus for distributed optimal reverse link scheduling of resources, such as rate and power, in a wireless communication systemUS7023900 *Dec 14, 2001Apr 4, 2006Samsung Electronics Co., Ltd.System and method for modifying peak-to-average power ratio in CDMA transmittersUS7031266Feb 25, 2000Apr 18, 2006Cisco Technology, Inc.Method and system for configuring wireless routers and networksUS7031283 *Sep 13, 2001Apr 18, 2006AlcatelMethod and system for enhancing channel capacity in a point to multipoint radio communications system having different kinds of terminalsUS7039095 *Mar 19, 2001May 2, 2006Matsushita Electric Industrial Co., Ltd.Receiving apparatus and gain control methodUS7046640Jun 29, 2001May 16, 2006Telefonaktiebolaget Lm Ericsson (Publ)Software analysis tool for CDMA systemUS7050409Feb 15, 2002May 23, 2006Wireless Facilities, Inc.Wireless T/E transceiver frame and signaling controllerUS7068624Feb 25, 2000Jun 27, 2006Cisco Technology, Inc.Wireless router and method for processing traffic in a wireless communications networkUS7110472 *Apr 1, 2002Sep 19, 2006Sony CorporationTransmission method, transmitter and receiverUS7113582 *Jan 27, 2003Sep 26, 2006Sprint Spectrum L.P.System for caller control over call routing pathsUS7126913Dec 3, 2002Oct 24, 2006Cisco Technology, Inc.Method and system for managing transmission resources in a wireless communications networkUS7230948Jun 1, 2001Jun 12, 2007Telefonaktiebolaget Lm Ericsson (Publ)Bandwidth efficient Quality of Service separation of AAL2 trafficUS7251218Oct 24, 2002Jul 31, 2007Van Drebbel Mariner LlcMethod and computer program product for internet protocol (IP)-flow classification in a wireless point to multi-point (PtMP) transmission systemUS7251252Jun 13, 2001Jul 31, 2007Qwest Communications International Inc.Negotiated cell delivery capabilityUS7263077 *Jan 21, 1998Aug 28, 2007Nokia CorporationPower control method of discontinuous transmissionUS7299402 *Feb 13, 2004Nov 20, 2007Telefonaktiebolaget Lm Ericsson (Publ)Power control for reverse packet data channel in CDMA systemsUS7310529 *Jan 24, 2000Dec 18, 2007Nortel Networks LimitedPacket data traffic control for cellular wireless networksUS7324459Sep 20, 2001Jan 29, 2008Nokia CorporationNegotiation of transmission parameterUS7346045 *Sep 4, 2001Mar 18, 2008Nokia CorporationMethod and system for bit rate adaptationUS7346354Feb 7, 2005Mar 18, 2008Cisco Technology, Inc.Method and system for dynamic soft handoff resource allocation in a wireless networkUS7359971Aug 10, 2006Apr 15, 2008Van Drebbel Mariner LlcUse of priority-based scheduling for the optimization of latency and jitter sensitive IP flows in a wireless point to multi-point transmission systemUS7359972Aug 10, 2006Apr 15, 2008Van Drebbel Mariner LlcTime division multiple access/time division duplex (TDMA/TDD) transmission media access control (MAC) air frameUS7369519 *Feb 27, 2004May 6, 2008Lg Electronics Inc.Method for determining threshold value for on/off controlling output power of mobile communication terminalUS7409450Feb 28, 2005Aug 5, 2008Van Drebbel Mariner LlcTransmission control protocol/internet protocol (TCP/IP) packet-centric wireless point to multi-point (PtMP) transmission system architectureUS7412517Aug 10, 2006Aug 12, 2008Van Drebbel Mariner LlcMethod for providing dynamic bandwidth allocation based on IP-flow characteristics in a wireless point to multi-point (PtMP) transmission systemUS7418028Aug 10, 2006Aug 26, 2008Wi-Lan, Inc.Agile RF band OFDM spread spectrum and cross-correlated systemsUS7426248Oct 25, 2006Sep 16, 2008Wi-Lan, Inc.Receivers and demodulators for TDMA and other modulated systemsUS7440488Dec 30, 2005Oct 21, 2008Kamilo FeherTDMA, spread spectrum RF agile filtered signal transmissionUS7450628Sep 25, 2006Nov 11, 2008Wi-Lan, Inc.Processor, modulators and transceivers for spread spectrum, CDMA, CSMA, OFDM, TDM, TDMA cross correlated and filtered systemsUS7457385Oct 24, 2006Nov 25, 2008Wi-Lan, Inc.Antenna systems, receivers and demodulators for cross-correlated and other signalsUS7460841 *Aug 29, 2005Dec 2, 2008Infineon Technologies AgCircuit arrangement and method for compensating for abrupt signal level changes in amplification devicesUS7463631Jul 15, 2004Dec 9, 2008Qualcomm IncorporatedMethod and apparatus for scheduling packet data transmissions in a wireless communication systemUS7480277 *Jan 2, 2003Jan 20, 2009Ntt Docomo, Inc.Signal transmission method and base station in mobile communicationUS7496674Aug 10, 2006Feb 24, 2009Van Drebbel Mariner LlcSystem, method, and base station using different security protocols on wired and wireless portions of networkUS7548787Aug 3, 2005Jun 16, 2009Kamilo FeherMedical diagnostic and communication systemUS7555054May 22, 2008Jun 30, 2009Wi-Lan, Inc.Methods and systems for transmission of multiple modulated signals over wireless networksUS7555272Jun 21, 2004Jun 30, 2009Infineon Technologies AgTransmission arrangement for transmitting data continuously in the time domainUS7558574May 7, 2007Jul 7, 2009Kamilo FeherVideo, voice and location finder wireless communication systemUS7561881Apr 29, 2006Jul 14, 2009Kamilo FeherAir based emergency monitor, multimode communication, control and position finder systemUS7593481 *Apr 24, 2004Sep 22, 2009Kamilo FeherCDMA, W-CDMA, 3rd generation interoperable modem format selectable (MFS) systems with GMSK modulated systemsUS7593733Oct 3, 2007Sep 22, 2009Kamilo FeherFingerprint identification, location finder communication systemUS7603125Oct 5, 2007Oct 13, 2009Kamilo FeherBarcode reader, location finder, GPS, navigational interactive TDMA, GSM, GPRS, EDGE, CDMA, OFDM, Wi-Fi wireless and wired systemUS7610393Feb 24, 2000Oct 27, 2009Alcatel-Lucent Usa Inc.Mobile IP supporting quality of serviceUS7627320Oct 26, 2007Dec 1, 2009Kamilo FeherVoice, location finder, modulation format selectable Wi-Fi, cellular mobile systemsUS7630717Jan 15, 2008Dec 8, 2009Kamilo FeherTouch screen, location finder, GSM, EDGE, CDMA cellular and OFDM, Wi-Fi systemUS7653735 *Mar 11, 2002Jan 26, 2010Sony Deutschland GmbhMethod for achieving end-to-end quality of service negotiations for distributed multi-media applicationsUS7668176 *Jan 18, 2001Feb 23, 2010Alcatel-Lucent Usa Inc.Universal mobile telecommunications system (UMTS) quality of service (QoS) supporting variable QoS negotiationUS7693102Aug 10, 2001Apr 6, 2010Nec CorporationCommunication system, method thereof, switching center thereof and base station control station thereofUS7693229Apr 14, 2008Apr 6, 2010Kamilo FeherTransmission of signals in cellular systems and in mobile networksUS7711368Oct 25, 2007May 4, 2010Kamilo FeherVoIP multimode WLAN, Wi-Fi, GSM, EDGE, TDMA, spread spectrum, CDMA systemsUS7720488Jun 21, 2007May 18, 2010Kamilo FeherRFID wireless 2G, 3G, 4G internet systems including Wi-Fi, Wi-Max, OFDM, CDMA, TDMA, GSMUS7725114Nov 21, 2009May 25, 2010Kamilo FeherWi-Fi, GPS and MIMO systemsUS7738608May 6, 2008Jun 15, 2010Kamilo FeherEqualized modulation demodulation (modem) format selectable multi antenna systemUS7764725Feb 10, 2004Jul 27, 2010Koninklijke Philips Electronics N.V.Sub-banded ultra-wideband communication systemUS7769386Oct 8, 2007Aug 3, 2010Kamilo FeherMIMO polar, non-quadrature, cross-correlated quadrature GSM, TDMA, spread spectrum, CDMA, OFDM, OFDMA and bluetooth systemsUS7783291Oct 21, 2008Aug 24, 2010Kamilo FeherTouch screen multiple input multiple output (MIMO) multimode wireless communicationUS7787882Mar 28, 2008Aug 31, 2010Kamilo FeherTouch screen generated processed signals in multiple communication systems and networksUS7801545 *Dec 30, 2004Sep 21, 2010Nokia CorporationPower control method of discontinuous transmissionUS7805143Oct 12, 2009Sep 28, 2010Kamilo FeherMobile video internet, cellular and location finder systemUS7809374Jun 30, 2009Oct 5, 2010Kamilo FeherVideo mobile communication systemUS7822041Jan 21, 2005Oct 26, 2010Qualcomm IncorporatedMethod and apparatus for scheduling packet data transmissions in a wireless communication systemUS7826384 *May 4, 2001Nov 2, 2010Nortel Networks LimitedMethod and apparatus for negotiating bearer control parameters using property setsUS7826463Feb 2, 2006Nov 2, 2010Cisco Technology, Inc.Method and system for configuring wireless routers and networksUS7830810 *Apr 12, 2001Nov 9, 2010Nokia CorporationDynamic DSCP availability request methodUS7848282 *Sep 29, 2006Dec 7, 2010Qualcomm IncorporatedMethod and apparatus for high rate packet data transmissionUS7848283Sep 29, 2006Dec 7, 2010Qualcomm IncorporatedMethod and apparatus for high rate packet data transmissionUS7848284Sep 29, 2006Dec 7, 2010Qualcomm IncorporatedMethod and apparatus for high rate packet data transmissionUS7848285Oct 2, 2006Dec 7, 2010Qualcomm IncorporatedMethod and apparatus for high rate packet data transmissionUS7877110Apr 27, 2010Jan 25, 2011Kamilo FeherCascaded 4G, 3G, 2G and other systemsUS7885650Apr 2, 2010Feb 8, 2011Kamilo FeherAdaptive coding and modulation with MIMO wireless and wired communicationUS7894810Oct 15, 2008Feb 22, 2011Kamilo FeherAutomobile wireless door opener and ignition starter by cellular deviceUS7899008Sep 24, 2003Mar 1, 2011Qualcomm, IncorporatedMethod and apparatus for scheduling packet data transmission in a wireless communication systemUS7899491Dec 14, 2008Mar 1, 2011Kamilo FeherCross-correlated quadrature modulated spread spectrum, OFDM and position finder systemUS7904041Oct 30, 2007Mar 8, 2011Kamilo FeherRemote control, cellular, WiFi, WiLAN, mobile communication and position finder systemsUS7917103Dec 15, 2008Mar 29, 2011Kamilo FeherWLAN and wired mobile communication and location finding systemUS7937093Apr 7, 2008May 3, 2011Kamilo FeherCellular and internet mobile systems and networksUS7937094Nov 26, 2008May 3, 2011Kamilo FeherWired and mobile wi-fi networks, cellular, GPS and other position finding systemsUS7944893Dec 11, 2008May 17, 2011Ntt Docomo, Inc.Signal transmission method and base station in mobile communicationUS7949405May 18, 2009May 24, 2011Kamilo FeherCardiac stimulation control and communication systemUS7961815Feb 6, 2009Jun 14, 2011Wi-Lan, Inc.Methods and systems for transmission of multiple modulated signals over wireless networksUS7978774Oct 21, 2007Jul 12, 2011Kamilo FeherInternet GSM, CDMA, OFDM, Wi-Fi wireless and wired multimode systemsUS7983678Dec 5, 2010Jul 19, 2011Kamilo Feher3G and Wi-Fi connected mobile systemsUS7990918May 23, 2006Aug 2, 2011Yoshimi Ltd., Limited Liability CompanyWireless T/E transceiver frame and signaling controllerUS7995531Sep 29, 2006Aug 9, 2011Qualcomm IncorporatedMethod and apparatus for high rate packet data transmissionUS8005042Oct 2, 2006Aug 23, 2011Qualcomm IncorporatedMethod and apparatus for high rate packet data transmissionUS8009625Sep 29, 2006Aug 30, 2011Qualcomm IncorporatedMethod and apparatus for high rate packet data transmissionUS8055269Feb 3, 2011Nov 8, 2011Kamilo FeherTime constrained signal MIMO wireless and wired communication methodUS8064409Aug 25, 1999Nov 22, 2011Qualcomm IncorporatedMethod and apparatus using a multi-carrier forward link in a wireless communication systemUS8068453Jun 25, 2003Nov 29, 2011Qualcomm IncorporatedMethod and apparatus for predicting favored supplemental channel transmission slots using transmission power measurements of a fundamental channelUS8077655Sep 29, 2006Dec 13, 2011Qualcomm IncorporatedMethod and apparatus for high rate packet data transmissionUS8081598Jan 13, 2004Dec 20, 2011Qualcomm IncorporatedOuter-loop power control for wireless communication systemsUS8085705Apr 29, 2011Dec 27, 2011Kamilo FeherWeb mobile systemsUS8089924Sep 29, 2006Jan 3, 2012Qualcomm IncorporatedMethod and apparatus for high rate packet data transmissionUS8098753May 22, 2009Jan 17, 2012Kamilo FeherInfrared, touch screen, W-CDMA, GSM, GPS camera phoneUS8112110Jul 16, 2011Feb 7, 2012Kamilo FeherPhone video mobile internet television (TV) and cellular systemUS8117291Jul 27, 2000Feb 14, 2012Wireless Technology Solutions LlcUse of internet web technology to register wireless access customersUS8150407 *Feb 6, 2004Apr 3, 2012Qualcomm IncorporatedSystem and method for scheduling transmissions in a wireless communication systemUS8150453Mar 3, 2011Apr 3, 2012Kamilo FeherCellular and TV interactive mobile wired and wireless systemsUS8185069Nov 2, 2011May 22, 2012Kamilo FeherWired and wireless 4G and 3G cellular, mobile and RFID systemsUS8189540Aug 21, 2009May 29, 2012Qualcomm IncorporatedMethod and apparatus for high rate packet data transmissionUS8189703Jul 10, 2011May 29, 2012Kamilo FeherTelevision mobile internet systemUS8190143Jan 28, 2012May 29, 2012Kamilo FeherTV internet and cellular mobile communicationUS8190193Nov 14, 2008May 29, 2012Kamilo FeherBluetooth, Wi-Fi, 3G quadrature and non-quadrature modulation methodsUS8200243May 2, 2011Jun 12, 2012Kamilo FeherMobile television (TV), internet, cellular systems and Wi-Fi networksUS8201039May 10, 2007Jun 12, 2012Qualcomm IncorporatedCombining grant, acknowledgement, and rate control commandsUS8213458Jun 25, 2007Jul 3, 2012Qwest Communications International Inc.Negotiated call delivery capabilityUS8254358Mar 12, 2004Aug 28, 2012Ericsson AbCommunicating a broadcast message to change data rates of mobile stationsUS8259822Oct 30, 2007Sep 4, 2012Kamilo FeherPolar and quadrature modulated cellular, WiFi, WiLAN, satellite, mobile, communication and position finder systemsUS8259832Oct 27, 2011Sep 4, 2012Kamilo FeherQAM and GMSK modulation methodsUS8306525May 16, 2012Nov 6, 2012Kamilo FeherUMTS wired and wireless mobile 2G, 3G, 4G, 5G and other new generations of cellular, mobileUS8311027Aug 3, 2006Nov 13, 2012Qualcomm IncorporatedMethod and apparatus for high rate packet data transmissionUS8311140Jan 15, 2012Nov 13, 2012Kamilo FeherInfrared, CDMA and OFDM signal transmission methodsUS8311509Oct 31, 2007Nov 13, 2012Kamilo FeherDetection, communication and control in multimode cellular, TDMA, GSM, spread spectrum, CDMA, OFDM WiLAN and WiFi systemsUS8325671 *Sep 6, 2007Dec 4, 2012Qualcomm IncorporatedMethods and apparatus for improved utilization of air link resources in a wireless communications system including a multi-antenna element base stationUS8351925Jun 8, 2012Jan 8, 2013Kamilo FeherDigital television (TV), ship and other water based interactive communication methodsUS8391245 *Aug 8, 2008Mar 5, 2013Panasonic CorporationTerminal device, base station device, and frequency resource allocation methodUS8391249Jun 30, 2003Mar 5, 2013Qualcomm IncorporatedCode division multiplexing commands on a code division multiplexed channelUS8463231Jul 27, 2000Jun 11, 2013Nvidia CorporationUse of radius in UMTS to perform accounting functionsUS8477592Mar 24, 2004Jul 2, 2013Qualcomm IncorporatedInterference and noise estimation in an OFDM systemUS8488459 *Feb 7, 2006Jul 16, 2013Qualcomm IncorporatedPower control and quality of service (QoS) implementation in a communication systemUS8489949Feb 17, 2004Jul 16, 2013Qualcomm IncorporatedCombining grant, acknowledgement, and rate control commandsUS8526966Jul 19, 2006Sep 3, 2013Qualcomm IncorporatedScheduled and autonomous transmission and acknowledgementUS8542715Jul 18, 2012Sep 24, 2013Kamilo FeherShip based cellular and satellite communicationUS8543153Aug 11, 2010Sep 24, 2013Nokia CorporationPower control method of discontinuous transmissionUS8547934 *Jun 4, 2009Oct 1, 2013Ntt Docomo, Inc.Radio communication method, radio controller, network device, radio base station and concentratorUS8548387Jan 2, 2007Oct 1, 2013Qualcomm IncorporatedMethod and apparatus for providing uplink signal-to-noise ratio (SNR) estimation in a wireless communication systemUS8576894Aug 18, 2010Nov 5, 2013Qualcomm IncorporatedSystems and methods for using code space in spread-spectrum communicationsUS8595478Nov 19, 2007Nov 26, 2013AlterWAN Inc.Wide area network with high quality of serviceUS20100226275 *May 21, 2010Sep 9, 2010Qualcomm IncorporatedFlow based fair scheduling in multi-hop wireless networksUS20110128875 *Jun 4, 2009Jun 2, 2011Ntt Docomo, Inc.Radio communication method, radio controller, network device, radio base station and concentratorUS20110222525 *Aug 8, 2008Sep 15, 2011Panasonic CorporationTerminal device, base station device, and frequency resource allocation methodUS20120134281 *Nov 29, 2010May 31, 2012Aydin OsmanMonitoring And Apparatus For Pre-Configuring Conditions For Data TransferUSRE40553 *Apr 22, 2005Oct 28, 2008Nec CorporationMethod and apparatus for adjusting transmission power of CDMA terminalCN1702980B *Mar 5, 2004May 26, 2010Lg电子株式会社Method for determining threshold value for on/off controlling output power of mobile communication terminalCN101047981BApr 25, 2006May 12, 2010华为技术有限公司System and method for implementing service quality consultation mechanismEP1111859A2 *Nov 20, 2000Jun 27, 2001Lucent Technologies Inc.Quality of service on demand for voice communications over a packet data networkEP1187370A1 *Mar 19, 2001Mar 13, 2002Lucent Technologies Inc.Integrating power-controlled and rate-controlled transmissions on a same frequency carrierEP1322051A1 *Mar 19, 2001Jun 25, 2003Lucent Technologies Inc.Integrated power-controlled and rate-controlled transmissions on a same frequency carrierEP1355433A1 *Apr 14, 2003Oct 22, 2003NTT DoCoMo, Inc.Radio station and radio network controllerWO1999030439A1 *Nov 12, 1998Jun 17, 1999L 3 Comm CorpFixed wireless loop system having adaptive system capacity based on estimated signal to noise ratioWO2001050278A1 *Dec 21, 2000Jul 12, 2001AppspointMethod and apparatus for invoking a variable bandwidth experience for an end-userWO2002025888A2 *Sep 20, 2001Mar 28, 2002Jani EkmanNegotiation of transmission parameterWO2003003775A2 *Jun 27, 2002Jan 9, 2003Ericsson Telefon Ab L MSoftware analysis tool for cdma systemWO2003056739A2 *Dec 17, 2002Jul 10, 2003Boos ZdravkoTransmission configuration for continuous-time data transmission* Cited by examinerClassifications U.S. Classification370/252, 375/146, 375/147, 370/333, 370/468International ClassificationH04J13/02, H04B7/005, H04W28/18, H04W52/26Cooperative ClassificationH04W52/265, H04W52/267, H04J13/00, H04W28/18European ClassificationH04W28/18, H04W52/26Q, H04W52/26R, H04J13/00Legal EventsDateCodeEventDescriptionOct 18, 2010PRDPPatent reinstated due to the acceptance of a late maintenance feeEffective date: 20101018Sep 28, 2010SULPSurcharge for late paymentSep 28, 2010FPAYFee paymentYear of fee payment: 12Sep 2, 2010ASAssignmentOwner name: SAMSUNG ELECTRONICS CO., LTD., KOREA, DEMOCRATIC PFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:CARLSON WIRELESS TECHNOLOGIES, INC.;REEL/FRAME:024927/0875Effective date: 20081030Jun 15, 2010FPExpired due to failure to pay maintenance feeEffective date: 20100428Apr 28, 2010REINReinstatement after maintenance fee payment confirmedNov 30, 2009REMIMaintenance fee reminder mailedOct 7, 2008ASAssignmentOwner name: CARLSON WIRELESS TECHNOLOGIES, INC., CALIFORNIAFree format text: CORRECTIVE ASSIGNMENT TO CORRECT THE NAME OF THE 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