Exploiting multiuser diversity through phase modulation multiplexing
A method and apparatus for combining signals of multiple users onto a common channel is disclosed. In one embodiment, the method comprises identifying one or more traffic channels that are of one or more predetermined quality levels to a plurality of subscriber units based on channel profiles of the plurality of subscriber units and transmitting phase modulation multiplexed signals to the plurality of subscriber units through a common set of one or more channels having higher quality than the one or more predetermined quality levels.
1 . A method comprising:
identifying at least one traffic channel having a maximum achievable data rate above a predetermined threshold, said traffic channel being utilized below said threshold;
identifying a plurality of low rate subscriber units, said identification of low rate subscriber units based, at least in part, upon a data rate of said subscriber unit over a period of time; and
transmitting phase modulation multiplexed signals on said at least one identified traffic channel to said plurality of identified low rate subscriber units, wherein said at least one traffic channel is shared by said plurality of low rate subscribers.
2 . The method of claim 1 wherein said identification of low rate subscriber units is based upon collecting the channel profiles of said low rate subscriber units.
3 . The method of in claim 1 wherein the low rate subscriber units comprise voice only subscriber units.
4 . The method of claim 1 wherein identifying at least one traffic channel is based on periodic traffic pattern analysis.
5 . (canceled)
6 . The method of claim 1 further comprising one of said plurality of low rate subscriber units demodulating at least a portion of the modulated multiplexed signals to obtain data for the one subscriber unit.
7 . The method of claim 6 wherein the one subscriber unit demodulates and decodes all of the modulated multiplexed signals to obtain data designated for the one subscriber unit.
8 - 16 . (canceled)
17 . A communication system comprising:
a base station transmitting phase modulation multiplexed signals to a plurality of low rate subscriber units over at least one traffic channel, at least two of said plurality of low rate subscriber units sharing at least one of said traffic channels;
said base station also transmitting signals to high rate subscriber units utilizing adaptive code modulation;
wherein said plurality of low rate subscriber units are identified as those having a data rate over a period of time below a threshold; and
wherein said high rate subscriber units are identified as those having a data rate over a period of time above said threshold.
18 . The communication system of claim 17 wherein the base station comprises:
a multiplexer to multiplex phase modulated signals for a plurality of low rate subscriber units onto a shared traffic channel; and
an adaptive coded modulation unit to transmit adaptive code modulated signals to high rate subscriber units.
19 . The communication system of claim 18 wherein the adaptive coded modulation unit jointly encodes the data stream to generate encoded data and maps the encoded data onto a QAM constellation.
20 . The communication system of claim 18 wherein the adaptive coded modulation unit comprises:
a channel encoder to channel code data from the data stream to generate encoded data; and
a modulator to perform modulation on the encoded data for wireless transmission on the traffic channel.
21 . The communication system of claim 20 wherein the modulator comprises a QAM modulator.
22 . The communication system of claim 21 wherein the channel encoder comprises a convolutional code encoder.
23 . The communication system of claim 21 wherein the channel encoder comprises a LDPC encoder.
24 . The communication system of claim 21 wherein the channel encoder comprises a Turbo encoder.
25 . The communication system of claim 21 wherein the channel encoder comprises a TPC encoder.
26 .- 46 . (canceled)
47 . A method comprising:
receiving, at a subscriber unit, low rate data transmissions from a base station;
transmitting, at said subscriber unit, channel profile information to said base station;
receiving, at said subscriber station and in response to said transmitting, phase modulation multiplexed signals from said base station on at least one traffic channel, said at least one traffic channel being shared by at least one other subscriber unit; and
decoding and demodulating said phase modulated multiplexed signals at said subscriber station.
48 . The method of claim 47 wherein said subscriber unit decodes and demodulates a portion of the modulated multiplexed signals to obtain data for said subscriber unit.
49 . The method of claim 47 wherein said subscriber unit decodes and demodulates all of the modulated multiplexed signals to obtain data for said subscriber unit.