Wireless Communication System Mapping Data Bits to Symbol Bit Positions According to Error Rates of Those Bit Positions and Data Content

• US 20110176590A1
• Filed: 10/20/2010
• Published: 07/21/2011
• Est. Priority Date: 10/20/2009
• Status: Active Grant

• Current Assignee: Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Original Assignee: Wisconsin Alumni Research Foundation (University of Wisconsin System)
• Inventors: Sen, Sayandeep, Banerjee, Suman
• Granted Patent: US 8,948,286 B2
• Time in Patent Office: Days
• US Class Current: 375/224
• CPC Class Codes: H04L 1/007 Unequal error protection for format H04L1/0078; for codes per se H03M13/35
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/203 Details of error rate determination, e.g. BER, FER or WER
• CPC Class Codes: H04N 19/89 involving methods or arrangements for detection of transmission errors at the decoder
• CPC Class Codes: H04W 28/04 Error control
• CPC Class Codes: H04W 4/18 Information format or content conversion, e.g. adaptation by the network of the transmitted or received information for the purpose of wireless delivery to users or terminals

Abstract

A transmitter-receiver pair encode data as transmitted symbols according to knowledge about variations in noise immunity between different bit positions of the symbols as a decoded. High usefulness data may be preferentially encoded at those bit positions having greatest noise immunity to improve transmission effectiveness.

Claims

1. A wireless transmitter comprising:

a physical transmitter transmitting symbols characterized by one or more parameters of a transmitted wireless signal that together define a constellation of symbols each mapping to multi-bit data units under an encoding system, bits of the multi-bit data units having bit positions;

a prioritizer dividing received multi-bit data units into at least two categories of relative high and low usefulness;

and interleaver receiving the multi-bit data units as divided into high and low usefulness and creating mixed multi-bit data units incorporating both high usefulness bits from high usefulness data units and low usefulness bits from low usefulness data units;

an encoder mapping the mixed multi-bit data units to symbols and providing the symbols to the physical transmitter for transmission according to the encoding system;

wherein the interleaver and encoder cooperate to map high usefulness bits to bit positions of symbols having relatively lower date error rates and to map low usefulness bits to bit positions of symbols having relatively higher bit error rates under the encoding system.

2. The wireless transmitter of claim 1 wherein the interleaver creates the mixed multi-bit data units according to a determination of bit error rates for mapping of multi-bit data units to symbols of the constellation under the encoding system so that high usefulness bits are mapped to bits having lower bit error rates and low usefulness bits are mapped to bits having higher bit error rates.

3. The wireless transmitter of claim 2 wherein the transmitter transmits periodic pilot symbols to a receiver whose value is known by the receiver independent of the transmission to determine bit error rates based on an evaluation of the pilot symbol by the receiver.

4. The wireless transmitter of claim 3 wherein the transmitter selects among the encoding system from a set of different encoding systems based on an evaluation of the bit error rates under the different encoding systems for the given channel conditions.

5. The wireless transmitter of claim 1 wherein the transmitter is a quadrature amplitude modulation transmitter and the constellation represents different amplitude values of two sinusoidal waves that are 90°

out of phase with each other.

6. The wireless transmitter of claim 1 wherein the received multi-bit data unit is an encoded video stream having frames of a plurality of multi-bit data units whose decoding depends on multi-bit data units from other frames and a usefulness is given to a given multi-bit data unit so that multi-bit data units having relatively greater numbers of dependencies have relatively lower usefulness.

7. The wireless transmitter of claim 1 wherein the encoding systems are selected from the group consisting of Grey, Block I, and Block II encoding.

8. A wireless receiver comprising:

a physical receiver, receiving from a transmitter wireless symbols characterized by one or more parameters of a transmitted wireless signal that together define a constellation of symbols each mapping to multi-bit data units under an encoding system, the multiple bits having bit positions;

a decoder mapping parameters of each received symbol to a multi-bit data unit according to an encoding system;

an error detector detecting an error in an erroneous multi-bit data unit received from the decoder but determined to be different from a corresponding multi-bit data unit transmitted by the transmitter;

an extractor receiving the erroneous multi-bit data unit characterized as having an error to extract bits from the given multi-bit data unit, the extracted bits having relatively lower data error rates for a particular encoding system than those bits not extracted;

a collector collecting extracted bits from multiple multi-bit data units to provide new multi-bit data units to be output from the receiver.

9. The wireless receiver of claim 8 wherein in the error detector detects the error through an error correction code associated with the given multi-bit data unit.

10. The wireless receiver of claim 8 wherein the receiver receives periodic pilot symbols from the transmitter whose value is known by the receiver independent of the transmission, and wherein the receiver determines bit error rates based on an evaluation of the pilot symbols as received against their known value and provides this information to a transmitter so that the extracted bits are in bit positions having low bit error rates.

11. The wireless receiver of claim 10 wherein the receiver evaluates the bit error rates using multiple encoding systems and wherein the encoding system used by the decoder is based on this evaluation.

12. The wireless receiver of claim 8 wherein the receiver is a quadrature amplitude modulation receiver and the constellation represents different amplitude values of two sinusoidal waves that are 90°

out of phase with each other.

13. The wireless receiver of claim 8 wherein the received symbols represent multi-bit data units of an encoded video stream having frames of a plurality of multi-bit data units whose decoding depends on multi-bit data units from other frames and wherein the extracted bits are portions of multi-bit data units having a fewer number of dependencies than the unextracted bits.

14. The wireless receiver of claim 8 wherein the encoding system is selected from the group consisting of Grey, Block I, and Block II encoding.

15. A transmitter and receiver system comprising:

a transmitter mapping multi-bit data units to individual symbols within a symbol constellation, the symbols representing discrete values within a range of physical parameters of a transmitted signal, the transmitter receiving multi-bit data units having different relative priorities and mixing bits from different multi-bit data units with different relative priorities to form multi-bit data units to be mapped to symbols;

at least one receiver detecting the symbols and mapping them to received multi-bit data units and detecting errors in the received multi-bit data units and extracting a portion of the bits of the multi-bit data units that are in error related to relatively higher usefulness multi-bit data units received by the transmitter.

16. The transmitter and receiver system of claim 15 wherein the transmitter and receiver cooperate to map bits from multi-bit data units having relatively higher priorities to bit positions of the symbols less susceptible to transmission error.

17. The transmitter and receiver system of claim 15 wherein the transmitter and receiver cooperate to test for bit error rates in different bits of multi-bit data units of the symbols for different encodings to select a preferred encoding and mapping within that encoding.

18. The transmitter and receiver system of claim 15 wherein the transmitter and receiver cooperate to test for bit error rates in different bit positions of the symbols for different encodings to select a preferred encoding and mapping within that encoding.