MXPA99010542A - Discontinuous transmission on high speed data channels - Google Patents

Abstract

The present invention is a method for efficiently utilizing spectrum resources belonging to a wireless communications system in the presence of data channels through a discontinuous data transmission technique. The discontinuous data transmission technique involves the transmission of a flag over a control channel (or some other communication channel) in frame f, wherein the flag would indicate to an intended recipient that a transmitter has a data frame to transmit to the recipient in some future frame f+q. In an embodiment, the transmitter would subsequently transmit the data frame over a data channel (or some other communication channel) in frame f+q if the flag indicated that the data frame was ready to be transmitted. In another embodiment, the transmitterwould not transmit the data frame unless the recipient has indicated (via another flag) that the recipient is ready to receive the frame of data from the transmitter.

Description

DISCONTINUOUS TRANSMISSION IN HIGH-SPEED DATA CHANNELS Field of the Invention The present invention relates generally to wireless communication systems and in particular to data transmissions over wireless communication systems. BACKGROUND OF THE RELATED TECHNIQUE The rapid growth of the Internet has unleashed the need to transmit data at high speeds. This need for high-speed data transmission has been met by service providers of wireless communication systems, but not by service providers of wireless communications systems. Currently, there are proposals to develop a wireless communication system based on multiple access technology with division of code (CDMA = Code Division Multiple Access) that has communication channels on which data can be transmitted at high speeds (referred to below as channels). of data or supplementary). However, dedicated spectrum resources for data channels would be inefficient due to the nature of bursts of data transmission. In other words, the data is transmitted in bursts followed by periods of inactivity REF: 32054 where data is not transmitted. Having spectrum resources dedicated to data channels during these periods of inactivity would be inefficient utilization of spectrum resources. Accordingly, there is a need for a wireless communication system that uses spectrum resources more efficiently in the presence of data channels. COMPENDIUM OF THE INVENTION The present invention relates to a method for efficient utilization of spectrum resources belonging to a wireless communication system having data channels for high speed data services. The present invention employs a discontinuous data transmission technique to more efficiently use spectrum resources. The discontinuous data transmission technique involves the transmission of a flag over a control channel (or some other communication channel) in frame f, where the flag will indicate to a intended recipient that a transmitter has a data box to send the recipient in some future frame f + q. In one mode, the transmitter will subsequently send the data box over a data channel (or some other communication channel) in the f + q box if the flag indicates that the data box was ready to transmit. In another mode, the transmitter will not transmit the data box, unless the recipient has indicated (by this flag transmitted on a control channel in an opposite direction), that the recipient is ready to receive the transmitter data box . Advantageously, the present invention avoids general configuration space of data channels, by making the data channels are already configured and waiting for data frame to arrive. Between active data transmissions, the frequency spectrum resources used by the transmitter can be shared with other users for more efficient use of the frequency spectrum. BRIEF DESCRIPTION OF THE DRAWINGS The features, aspects and advantages of the present invention will be better understood with respect to the following description, appended claims and accompanying drawings in which: Figure 1 illustrates a wireless communication system based on CDMA used in accordance with the present invention; Figure 2 illustrates a base station communicating with a mobile telephone via a forward link, and a return link, - Figure 3 illustrates a simplified schematic diagram for a CDMA based transmitter implementation of CDMA; Figures 4 and 5 illustrate flow diagrams showing a discontinuous transmission technique for forward links, according to the present invention, - Figure 6 illustrates a simplified schematic diagram for an implementation of an MT transmitter based on CDMA 60; and Figures 7 and 8 illustrate flow charts showing a discontinuous transmission technique for reverse links according to the present invention. DETAILED DESCRIPTION The present invention will be described herein with reference to wireless communication systems, based on Multiple Access Code Division (CDMA) technology. However, the limitation of the present invention to the CDMA-based wireless communication systems described herein should not be considered. The present invention can equally be applicable to wireless communication systems, based on other multiple access technologies, such as Time Division Multiple Access (TDMA = Time Division Multiple Access) and Multiple Access with Frequency Division (FDMA = Frequeney Division) Multiple Access).

Figure 1 illustrates a wireless communication system based on CDMA 10 used in accordance with the present invention. The wireless communication system 10 comprises the mobile switching center (MSC = mobile switching center) 12 and the base stations (BS = base stations) 14-i, to provide wireless communications services to mobile telephones (MT = mobile-telephones) 16-k within its associated cells 17-i. Each of the base stations 14-i is connected to the MSC 12 by connections, such as lines T-1, not shown and is operable to communicate with MT 16-k over a prescribed frequency spectrum. Communication is achieved between BS 14-i and MT 16-Je by the transmission of signals (from and to the base stations) over a variety of communication channels in the prescribed frequency spectrum, where communication channels for the transmission of BS signals 14-ia MT 16 -k are referred to herein as forward and communications link channels, for the transmission of signals from MT 16-J to BS 14-i, referred to herein as a reverse link. The outbound link using a first portion of the prescribed frequency spectrum and the reverse link, using a second portion of the prescribed frequency spectrum. Figure 2 illustrates a base station 14-i communicating with the mobile telephone 16-Jc via the forward link 20 and the reverse link 22. The forward link 20 comprises dedicated forward control channels (F-DCCH = forward dedicated control channels) to transmit control information, fundamental outbound channels (F-FCH = forward fundamental channels) to transmit voice channels, one-way (F-SCH = forward supplemental channels), to transmit data and pilot outbound channels (F-PC = forward pilot channels) to transmit pilot information. The reverse link 22 comprises a dedicated reverse control channel (R-DCCH = reverse dedícate channel) to transmit control information, a fundamental reverse channel (R-FCH = reverse fundamental channel) to transmit voice, a supplementary channel of Reverse (R-SCH = reverse supplemental channel) to transmit data and a reverse pilot channel (R-PC = reverse pilot channel) to transmit pilot information. The forward and reverse pilot channel signals are used for coherent demodulation of the dedicated, fundamental and supplementary control channel signals of forward and reverse link. The manner in which the outbound link 20 and reverse link 22 communication channels are defined depends on the specific implementation of the wireless communication system. A particular embodiment will be described herein, but will not be construed as limiting the present invention in any way. To illustrate the signal processing for forward link 20, a simplified schematic diagram for an implementation of a BS transmitter based on CDMA 30 for the base station 14-i is illustrated in Figure 3. The transmitter BS 30 receives a plurality of Sbsm power signals, where m = 0, ... 44. For purposes of illustration, the signal Ssb0 is pilot information (which in one embodiment is a DC voltage signal generated by the transmitter BS 30), the signal S6 ^ is synchronization information, the signals Sbs2-Sbs3 are radio location information , signal Sbs4 is common control information, signals Sbs5 - Sbs24 are voice, and signals ibe - ShB ?? are data signals Sbs - S bs 44 44 (or signals Sbep) are provided as cipher feeds 32 -p, where p = 2, ..., 45. In the 32-p encoder, the signals -.bs SbBA are combined with a common long code decimated and the signals Sbs5 - Sbs44 are combined with z codes of long pseudo-random numbers (PN) to produce the output signals Sbs (34), where the long z PN codes they are secret or private codes associated with the users z for which the signals Sbs5 - -.be bs 44 are intended. It should be noted that more than one SD (34) can be intended for the same user z. The signals Sbs0 Sbs and Sbsp (34) are multiplied with Walsh codes Vm (in the multiplier 36-m) to produce the output signals Sbs? N (38), where Walsh V¡m codes are orthogonal functions used to define different communication channels in BS 14-i. Thus, in BS 14-i, the forward pilot channel is defined using the Walsh W0 code, the synchronization channel is defined using the Walsh Wx code, the radio localization channels are defined using the Walsh codes W2-W4, the common one-way control channel is defined using Walsh W4 code, the fundamental one-way channels are defined using the Walsh W5-W24 codes, and the one-way supplementary channels are defined using the Walsh codes 25-W44. The signals Sbem (38) are attenuated by the variable attenuator 4.0 -m to produce the output signals Sbsm (42). The amount that each individual signal SbsJI] (38) is attenuated, varies according to a number of system parameters, such as radio frequency conditions (RF = Radio Frequeney), etc. The signals Sbe: p (42) are sum together for the adder 44 to produce the output signal Sbs (46), which is then provided as feeds to the multipliers 48 and 50. In the multipliers 48 and 50, the signal Sbs (46) is multiplied with a pair of short PN codes (which are different from the long PN codes) to produce signals Sbe (52) and Sbs (54). Specifically, the output signal Sbs (46) is multiplied by PN-Ii and PN-Qi, where PN-Ii and PN-Qi are PN codes in phase (I) and quadrature (Q), which have a synchronization index or phase shift associated with BS 14-i. Signals Sbs (52) and Sbs (54) are subsequently modulated into omegact and sen omegact carrier signals, summed and transmitted as forward link 20. In this way, Figure 3 illustrates a round trip link 20 including a pilot channel one way, one synchronization channel, two radio localization channels, one common one-way control channel, twenty fundamental one-way channels and twenty one-way supplementary channels. It should be noted that this will not be considered as limiting the forward link of the present invention in any way. The Sbsm power signals are processed and transmitted by the BS 30 transmitter over a series of frames (or time slots) of 20 ms duration. For purposes of this application, the term "process" shall be considered to include coding and / or modulation, when employed in the context of transmitting and include demodulating and / or decoding, when used in the receiving context, and the term "frames" shall not be limited to 20 ms time intervals. The present invention uses a discontinuous transmission technique in forward link 20, to take into account the nature of data transmission bursts, resulting in a more efficient use of spectrum resources. Specifically, the present invention utilizes a dedicated forward control channel, such as a paging channel (or other forward communication channel) to transmit forward (or indicate bit) transmission flags in the frame f, which will indicate to one or more MT 16-Je processing incoming data transmission received on the assigned one-way supplementary channel MT 16-Je (or other forward communication channel) in the table f + q, where f represents the current frame , f + q represents some future picture, and g may already be a constant value or a variable. Figures 4 and 5 illustrate flow charts 400 and 500, showing the discontinuous transmission technique of the present invention for forward links deployed by BS 14-i and MT-Je, respectively. As illustrated in Figure 4, (for BS 14-i), in step 410, BS 14-i (or a base station controller) determines whether data is transmitted to MT 16-Je in table f + q about F-SCH assigned to MT 16-Je's. If BS 14-i is ready to transmit data, a positive forward transmission flag (having a value of 1) is transmitted in frame f in step 420, where a positive forward transmission flag will indicate to the mobile telephone 16-What data will be, (or are ready to) be, transmitted in the f + q box on F-SCH assigned to 16-Je's. Otherwise, in step 430, BS 14-i transmits a negative forward transmission flag (which has a value of 0) in frame f, where a negative forward transmission flag will indicate to the mobile telephone 16-Je that data will not be transmitted in table f + q on F-SCH assigned to MT 16-Je 's. By contrast, as illustrated in Figure 5, (for MT 16-Je) in step 510, MT 16-Je verifies the f-frame of F-DCCH, to determine whether the received frame f is valid (ie without error in F-DCCH frame f transmission). If the table f is invalid, MT 16-Je will try to process the f + q table of its F-SCH, in step 530 (in order to reduce the number of retransmissions of the same data by BS 14-i). If frame f of F-DCCH is valid, in step 520, MT 16-Je will verify the forward transmission flag transmitted in frame f. If the forward transmission flag is positive, MT 16-Je proceeds to step 530 where it processes the f + q of R-SCH of MT 16-Je's. If the forward transmission flag is negative, MT 16-Je will not process the f + q of R-SCH of MT 16-Je's. It should be noted that BS 14-i and MT 16-Je use a protocol that will allow MT 16-Je to distinguish the forward transmission flag from other transmitted bits on F-DCCH (or other forward communication channel). In one embodiment, the forward transmission flag is a bit in a known position with respect to the frame boundary or an additional supplementary channel or mobile telephone identifier, such that the forward transmission flag is easily identifiable where the mobile telephone and the one-way supplementary channel identifier (which can be transmitted on the same or different communication channel) indicate MT 16-Je or one-way supplementary channel, to which the forward transmission flag is intended or on which the data will be transmitted. The decision of when to transmit data to MT 16-Je (or if a positive or negative forward transmission flag is transmitted) in a modality, it is determined by BS 14-i, a base station controller, or some other entity or device that handles (or is aware of) the available spectrum resources. In this mode, BS 14-i (or the base station controller) examines the available spectrum resources for the RF and forward link conditions of its associated cells before determining which frame the data is to be transmitted to MT 16- Je. For example, assuming that there are two MT-L and MT2 mobile phones to which fundamental outbound channels are assigned (ie two data users). There are good RF conditions between BS 14-i and MTX but bad RF conditions exist between BS 14-i and MT2. Because MTX has good associated RF conditions, intended signals for MT will require less attenuation (by the attenuator 40 -m) than the signals intended for MT2. Less attenuation will result in lower consumption of spectrum resources per MT-L than per MT2. Since MT-L consumes less spectrum resources than MT2, BS 14-i (or base station controller) can transmit data frames more frequently to MTX than to MT2. In an alternate modality, a program or randomness can be used to specify which forward transmission flag is transmitted by BS 14-i to MT 16-Je. To illustrate signal processing for reverse link 22, a simplified schematic diagram for an implementation of a CDMA transmitter based on CDMA 60 for the mobile telephone 16-Je, is illustrated in Figure 5. The transmitter MT 60 receives a plurality of signals of power S11111 ^, where ^ = 0, ..., 5. For purposes of illustration, the Smt0 signal is pilot information, the Smt1-Smt2 signals are access messages, the Smt3 signal is common control information, the Smt4 signals are voice and the Smt5 signal is data. The Smtx signals are provided as feeds to multipliers 62 -x where the Smtx signals are multiplied by Walsh codes 0-W5, respectively, to produce Smtx output signals (64). The signals Stn_! Í (64) are summed together by the adder 66 to produce the signal Smt (68). The encoder 70 multiplies the signal Sm (68) with the long PN code (associated with the user z of the mobile telephone 16-Je) to produce the output signal Smt (72). The signal Smt (72) is multiplied by multipliers 74 and 76 using the same pairs of short PN codes (used by BS-i but with a phase shift index or zero synchronization) to produce the signal in Sm phase (78) and the quadrature signal Smt (80), which are then modulated into omegac and sen omegact carrier signals, summed and transmitted as a reverse link 22. In this way, Figure 5 illustrates a reverse link 22 including a pilot channel of Reverse, two random access channels, a common reverse control channel, a fundamental reverse channel and a supplementary reverse channel. It should be noted that this will not however be considered as limiting the reverse link of the present invention in any way. The Smt power signals are processed and transmitted by the MT 60 transmitter over a series of frames (or time slots) of 20 ms duration. As the forward link 20, the present invention uses a discontinuous transmission technique in the reverse link 22 to take into account the nature of the data transmission burst, resulting in more efficient use of spectrum resources. The present invention utilizes a dedicated outbound control channel such as a radio location channel (or other forward communication channel) to transmit reverse reception flags (or indicator bits) in the frame f, which will indicate one or more MT 16-Je that BS 14-i is ready to receive data on the supplementary reversing channel MT 16-Je's (or other reverse communication channel) in the g + r box, and a dedicated reverse common control channel ( or another reverse communication channel) to send reverse transmission flags (or indicator bits) in the g-frame, which will indicate to BS 14-i that MT 16-Je has data to transmit on the supplementary reverse channel MT 16-Je's (or other reverse communication channel) in the square g + r where gyf may or may not correspond to the same time interval of a communication channel equal or different, and r is a constant or variable. The notations g and f shall not be considered to refer to a specific address (ie reverse or one way). Figures 7 and 8 illustrate flow charts 600 and 700 showing the discontinuous data transmission technique of the present invention, for reverse links employed by BS 14-i and MT 16-Je, respectively. As illustrated in Figure 7 (for BS 14-i), in step 610, BS 14-i (or a base station controller) determines whether MT 16-Je is allowed to transmit data to BS 14-ia a table g + r on R-SCH of MT 16-Je's. If BS 14-i is ready to receive data from MT 16-Je, in step 630, a positive reverse reception band (having a value of 1) is transmitted in frame f over F-DCCH, where the Positive reverse reception flag will indicate to mobile phone 16-Je that BS 14-i will be ready to receive data transmission in the g + r box on R-SCH of MT 16-Je's. Otherwise, in step 620, BS 14-i transmits a negative reverse reception flag (having a value of 0) in the frame f over F-DCCH, where the negative reverse reception flag will indicate the telephone mobile 16-Je that BS 14-i is not ready to receive data transmission in the table g + r on R-SCH of MT 16-Je's. If BS 14-i transmits a positive reverse reception flag, in step 650, BS 14-i checks the g-frame of R-DCCH of MT 16-Je's, to determine whether the received frame g is valid (ie there is no transmission error of the R-DCCH chart of MT 16-Je's). If frame g is valid in step 660, BS 14-i will check to determine if the reverse transmission band in frame g is positive or negative, where a positive reverse transmission flag (which has a value of 1 ) will indicate BS 14-i that MT 16-Je has data to transmit and is ready to transmit data in frame g + r on R-SCH of MT 16-Je 's and a flag of reverse transmission (has a value of 0) will indicate to BS 14-i that MT 16-Je has no data to transmit on R-SCH of MT 16-Je's. If the table g is invalid or if BS 14-i receives a positive reverse transmission flag in the R-DCCH table ^ of MT 16-Je's, then BS 14-i will process the g + r table of R-SCH from MT 16-Je's in step 670. But if BS 14-i receives a negative reverse transmission flag in frame g of R-DCCH of MT 16-Je's, BS 14-i will not process the frame g + r of R- SCH of MT 16-Je's. As illustrated in Figure 8 (for MT 16-Je), in step 710, MT 16-Je determines whether it has data to transmit a frame g + r from its R-SCH to BS 14-i. If MT 16-Je has no data to transmit, MT 16-Je sends a negative reverse transmission flag in frame g of its R-DCCH, in step 720, and then turns off (or does not process for) the frame g + r of its R-SCH, in step 760. Otherwise in step 730, MT 16 -k sends a positive reversal transmission flag. When sending a positive reversal transmission flag as in step 750, MT 16-Je checks the f-frame of F-DCCH. If the reverse transmission flag is positive (ie the reverse transmission flag is not negative and the f-DCCH table f is valid), in step 770, MT 16-Je transmits data in the g + r table of his R-SCH. Otherwise, MT 16-Je turns off its R-SCH in the g + r box.

As the outgoing link BS 14-i and MT 16-Je will use some kind of protocol that will allow BS 14-i and MT 16-Je to distinguish the flags of reverse transmission and reverse reception of other bits transmitted on R-DCCH (or other reverse communication channel) and F-DCCH (or other forward communication channel), respectively. In one embodiment, the reverse reception flag is a bit at a known position with respect to the frame boundary or a mobile telephone identifier such that the reverse reception flag is easily identifiable, and the reverse transmission flag is a bit in a known position with respect to the frame boundary. The decision whether to transmit a positive or negative reverse reception flag in a modality is determined by BS 14-i (or base station controller) or some other entity or device that manages (or has knowledge of the resources of) available spectrum . In this mode, BS 14-i examines the available spectrum resources for the RF and outbound link conditions of its associated cell, before determining which reverse reception flag transmits to MT 16-Je. Alternatively, a program or randomness can be used to specify which reverse reception flag is to be transmitted by BS 14-i to MT 16-Je.

In the reverse link, MT 16-Je will send a positive reverse transmission flag (via the common reverse control channel) if MT 16-Je has data to transmit to BS 14-i over the supplementary reverse channel MT 16 -Je's. Conversely, MT 16-Je will send a negative reverse transmission flag if MT 16-Je has no data to transmit to BS 14-i over the supplementary reverse channel MT 16-Je's. Although the present invention has been described in considerable detail with reference to certain embodiments, other versions are possible. For example, flags and data can be transmitted over the same communication channel or different communication channels, or flags can be transmitted over fundamental channels. In addition, flags can comprise multiple bits. Therefore, the spirit and scope of the present invention will not be limited to the description of the modalities contained herein. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (10)

1. CLAIMS Having described the invention as above, sa raclata cano ptpiß3ad the aj-tencb in the following rejvip if7rtirttR: 1. A method for transmitting data frames on a communications channel, characterized in that it comprises the steps of: transmitting a transmission flag on a first communications channel in a f-frame to indicate whether a data frame is ready to be transmitted in a frame f + q over a second communication channel; and transmitting the data frame in the f + q box on a second communication channel, if the transmission flag is a positive transmission flag indicating that the data frame is ready to be transmitted in the frame f + q.
2. 2. The method according to claim 1, characterized in that it further comprises the step of: receiving a reception flag on a third communication channel in a frame g, to indicate whether the data table is ready to be received in the table f + q, where the data box is transmitted to the f + q box, if the reception flag is a positive reception flag indicating that the data box is ready to be received in table f + g.
3. 3. The method according to claim 2, characterized in that the data frame is not transmitted in frame f + q on the second communication channel if the reception flag is a negative reception flag indicating that the data frame is not is ready to be received in the f + q box.
4. The method according to claim 1, characterized in that the data frame is not transmitted in frame f + q over the second communication channel if the transmission flag is a negative transmission flag, indicating that the data frame it will not be transmitted in the f + q box.
5. The method according to claim 1, characterized in that it comprises the additional step of: transmitting a mobile telephone identifier on a third communication channel to indicate a mobile telephone to which the transmission flag is intended.
6. The method according to claim 1, characterized in that it comprises the additional step of: transmitting a communication channel identifier on a third communication channel to indicate a communication channel in which the transmission flag is to be sent.
7. A method for receiving transmitted data frames on a communication channel, characterized in that it comprises the steps of: receiving a transmission flag on a first communication channel in a frame g, to indicate whether a data frame is ready to be transmitted in a box g + r; and process the data frame transmitted in the g + r box of a second communication channel, if the transmission flag is a positive transmission flag that indicates that the data frame is ready to be transmitted in the g + r box on the second communications channel.
8. A method according to claim 7, characterized in that the frame g + r of the second communications channel is not processed if the transmission flag is a negative transmission flag indicating that data frames will not be transmitted in the g + box r.
9. 9. A method according to claim 7, characterized in that the frame g + r of the second communication channel is processed if an error occurred with respect to the transmission flag in the g-frame of the first communication channel. A method according to claim 8, characterized in that it comprises the additional step of: transmitting a reception flag in the frame f on a third communication channel, to indicate whether a recipient is ready to receive the data box in the g + r box transmitted on the second communication channel.