MAXIMIZING DATA RATE BY ADJUSTING CODES AND CODE RATES

• US 20090135950A1
• Filed: 12/02/2008
• Published: 05/28/2009
• Est. Priority Date: 03/05/1999
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Inventors: Proctor, James A. Jr., Rouphael, Antoine J., Hoffmann, John E., Riley, Daniel I., Nelson, George Rodney Jr.
• Granted Patent: US 8,204,140 B2
• Time in Patent Office: Days
• US Class Current: 375/298
• CPC Class Codes: G11B 20/1833 by adding special lists or symbols to the coded information G11B20/1806, G11B20/1866 take precedence
• CPC Class Codes: H03M 13/35 Unequal or adaptive error protection, e.g. by providing a different level of protection according to significance of source information or by adapting the coding according to the change of transmission channel characteristics
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04J 13/00 Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0007 by modifying the frame length
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0048 in conjunction with detection of multiuser or interfering signals, e.g. iteration between CDMA or MIMO detector and FEC decoder for spatial equalizer H04L25/03286
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 1/1816 with retransmission of the same, encoded, message
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 2001/0096 Channel splitting in point-to-point links
• CPC Class Codes: H04L 25/14 Channel dividing arrangements , i.e. in which a single bit stream is divided between several baseband channels and reassembled at the receiver
• CPC Class Codes: H04L 27/22 Demodulator circuits; Receiver circuits
• CPC Class Codes: H04L 27/38 Demodulator circuits; Receiver circuits

Abstract

The present invention provides for making code rate adjustments and modulation type adjustments in a pseudonoise (PN) encoded CDMA system. Coding rate adjustments may be made by changing the number of information bits per symbol, or Forward Error Code (FEC) coding rate. A forward error correction (FEC) block size is maintained at a constant amount. Therefore, as the number of information bits per symbol are increased, an integer multiple of bits per epoch is always maintained. The scheme permits for a greater flexibility and selection of effective data rates providing information bit rates ranging from, for example, approximately 50 kilobits per second to over 5 mega bits per second (Mbps) in one preferred embodiment.

Claims

1. A subscriber unit comprising:

a forward error correction (FEC) decoder conFig.d to decode a plurality of data blocks, wherein each of the plurality of data blocks is a fixed size and encoded with an error correction code, and to generate a plurality of decoded segments based on the plurality of data blocks, wherein each of the decoded segments is a variable number of data bits.

2. The subscriber unit of claim 1, wherein the FEC decoder is conFig.d to decode each of the plurality of data blocks based on a decoding rate.

3. The subscriber unit of claim 2, wherein a size of each of the plurality of decoded segments is based on the decoding rate.

4. The subscriber unit of claim 3, further comprising:

a controller conFig.d to select a decoding rate and to signal the selected decoding rate to the FEC decoder.

5. The subscriber unit of claim 4, further comprising:

a segment disassembler conFig.d to generate a data frame based on the plurality of decoded segments

6. The subscriber unit of claim 1, further comprising:

a demodulator conFig.d to demodulate a received signal and to generate the plurality of data blocks.

7. The subscriber unit of claim 6, wherein the demodulator is conFig.d to demodulate the received signal using a Quadrature Phase Shift Keying (QPSK) modulation scheme.

8. The subscriber unit of claim 6, wherein the demodulator is conFig.d to demodulate the received signal using a Quadrature Amplitude Modulation (QAM) modulation scheme.

9. A method for use in a subscriber unit, the method comprising:

decoding a plurality of data blocks, wherein each of the plurality of data blocks is a fixed size and encoded with an error correction code; and

generating a plurality of decoded segments based on the plurality of data blocks, wherein each of the plurality of decoded segments is a variable number of data bits.

10. The method of claim 9, wherein the decoding is performed based on a decoding rate.

11. The method of claim 10, wherein a size of each of the plurality of decoded segments is based on the decoding rate.

12. The method of claim 10, further comprising:

selecting a decoding rate, wherein a size of each of the plurality of decoded segments is based on the decoding rate

13. The method of claim 9, further comprising:

generating a data frame based on the plurality of decoded segments.

14. The method of claim 9, further comprising:

demodulating a received signal to produce the plurality of data blocks.

15. The method of claim 14, wherein the demodulating uses a Quadrature Phase Shift Keying (QPSK) modulation scheme.

16. The method of claim 14, wherein the demodulating uses Quadrature Amplitude Modulation (QAM) modulation scheme.