Granted Patent B2

US 8,102,946 · App. 12/168,480 · Granted Jan 24, 2012

Abstract

Claims (48)

1. A communication system comprising:

a soft-output detector configured to receive a transmit signal and output reliability information regarding the received signal, wherein the detector comprises a symbol combiner configured to operate in both a repetition mode and a non-repetition mode, wherein repetition mode comprises receiving a plurality of signals for the transmit signal, wherein the detector further comprises:

a rescaling block configured to scale a real and imaginary component of the received transmit signal by a factor to de-normalize the received signal and rescale the signal to a point in an odd integer 1-D grid; and

a saturation block configured to saturate the de-normalized received signal.

2. The system of claim 1 , wherein the received signal is a single-input single-output (SISO) signal in a WiMAX (Worldwide Interoperability for Microwave Access) environment, and wherein the reliability information comprises bit-wise log likelihood ratio (LLR).

3. The system of claim 1 , wherein the symbol combiner is configured to combine a plurality of received signals associated with the transmit signal into a single signal in response to receiving the transmit signal in repetition mode.

4. The system of claim 3 , wherein the symbol combiner combines the plurality of received signals by performing maximum ratio combining (MRC) to generate a single signal, and wherein the symbol combiner is further configured to perform zero-forcing (ZF) equalization on the transmit signal in response to receiving the transmit signal in non-repetition mode.

5. The system of claim 4 , wherein the detector further comprises a demodulator, wherein the demodulator is configured to receive the single signal from the symbol combiner and demodulate the single signal and output reliability information.

6. The system of claim 5 , wherein the demodulator comprises one or a plurality of amplitude shift key (ASK) demodulators.

7. The system of claim 1 , wherein the factor is based on a modulation order of the transmit signal such that the factor comprises:

2

4

for a modulation order of 2;

√{square root over (10)} for a modulation order of 4; and

√{square root over (42)} for a modulation order of 6.

8. The system of claim 1 , wherein the received signal is saturated to ±√{square root over (2 M )}, wherein M represents a modulation order of the transmit signal.

9. A method comprising:

receiving a WiMAX (Worldwide Interoperability for Microwave Access) transmit signal;

in response to receiving the transmit signal via a repetition protocol, combining a plurality of signals received via the repetition protocol into a single signal;

scaling a real and imaginary component of the single signal by a factor to de-normalize the received signal and rescale the signal to a point in an odd integer 1-D grid single symbol;

performing saturation on the de-normalized received signal by saturating the de-normalized received signal to ±√{square root over (2 M )}, wherein M represents a modulation order of the transmit signal;

demodulating the single signal; and

providing reliability information regarding the demodulated symbol.

10. The method of claim 9 , wherein the received signal is a single-input single-output (SISO) signal, and wherein the reliability information comprises bit-wise log likelihood ratio (LLR).

11. The method of claim 9 , wherein the factor is based on a modulation order of the transmit signal such that the factor comprises:

2

4

for a modification order of 2;

√{square root over (10)} for a modulation order of 4; and

√{square root over (42)} for a modulation order of 6.

12. The method of claim 9 , wherein demodulating the single signal comprises demodulating the scaled and saturated received signal.

13. The method of claim 9 , wherein combining the plurality of signal into a single signal comprises performing maximum ratio combining (MRC).

14. The method of claim 9 , further comprising: in response to receiving a single signal for the transmit signal, performing zero-forcing (ZF) equalization on the transmit signal.

15. A communication system comprising:

means for receiving a transmit signal in a WiMAX (Worldwide Interoperability for Microwave Access) environment;

means for combining a plurality of signals into a single signal when the plurality of signals is received for the transmit signal;

means for performing zero-forcing (ZF) equalization on the transmit signal when a single signal is received;

means for scaling a real and imaginary component of the single signal by a factor to de-normalize the received signal and rescale the signal to a point in an odd integer 1-D grid single symbol; and

means for performing saturation on the de-normalized received signal by saturating the de-normalized received signal to ±√{square root over ( )}(2^M), wherein M represents a modulation order of the transmit signal.

16. The system of claim 15 , wherein the factor is based on a modulation order of the transmit signal such that the factor comprises:

2

4

for a modulation order of 2;

√{square root over (10)} for a modulation order of 4; and

√{square root over (42)} for a modulation order of 6.

17. The system of claim 15 , further comprising:

means for demodulating the scaled and saturated received signal; and

means for providing a bit-wise log likelihood ratio (LLR) for the transmit signal.

Assignments (8)