Reverse-link structure for a multi-carrier communication system

• US 20060268883A1
• Filed: 04/17/2006
• Published: 11/30/2006
• Est. Priority Date: 04/18/2005
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Via Telecom Co., Ltd.
• Inventors: Czaja, Stanislaw, Qian, Feng, Yang, Hong Kui
• Granted Patent: US 7,672,286 B2
• Time in Patent Office: Days
• US Class Current: 370/394
• CPC Class Codes: H04J 13/0048 Walsh
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/1607 Details of the supervisory signal
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems

Abstract

A method and system for providing acknowledgment and/or data rate control (DRC) information with respect to data packets conveyed on a plurality of active forward link (FL) carriers. The number of reverse link (RL) carriers employed for the acknowledgment and/or DRC information may be less than the number of active FL carriers, and may be a single carrier, even when the signaling protocol is, in the limit, consistent with presently-supported standardized CDMA protocols. Code multiplexing techniques are employed inventively to convey information for up to fifteen FL carriers on a single, standard CDMA channel designed to provide such signaling for only a single FL carrier at a time.

Claims

1. A method of asymmetrically receiving data from a particular data source station at a data receiver, comprising:

a) concurrently receiving a plurality of different data packets transmitted concurrently from the source via a corresponding plurality of different forward link channels that each modulate a different carrier frequency spectrum;

b) determining acknowledgment status for each data packet as ACK if it was received correctly, or as NAK if it was received incorrectly;

c) multiplexing acknowledgment symbols reflecting the different data packets onto a reverse link (RL) acknowledgment channel after imposing a corresponding different multi-bit orthogonal code cover on the acknowledgment symbols; and

d) transmitting the RL acknowledgment channel to the data source station by modulating a single carrier frequency spectrum.

2. The method of claim 1, wherein step (d) further comprises conforming to protocols standardized for a previous version of a CDMA communication system in that

i) the acknowledgment status of each of the data packets is mapped to a signal to form the basis of an acknowledgment symbol pattern,

ii) the reverse link acknowledgment channel carrier frequency has a same relationship to a first one of the forward link channels as in the previous version, and

iii) the reverse link acknowledgment channel is spread using a same orthogonal code and occupies a same transmit time interval (TTI) as in the previous version.

3. The method of claim 1, wherein the multi-bit orthogonal code covering and repetition of the acknowledgment symbols results in a sequence having a same duration, occupying a same transmit time interval (TTI), and being subsequently modulated by a same Walsh code as standardized for a previous version of a CDMA communication system.

4. The method of claim 3, wherein the multi-bit orthogonal code cover is a length-16 Walsh code cover, and the sequence after repetition has a length of 32 symbols.

5. The method of claim 4, wherein an order of the steps includes performing the length-16 Walsh code covering of the acknowledgment symbols derived from the acknowledgment status of each of the different packets and combining into a single length-16 sequence, then repeating the sequence, and then modulating with the same orthogonal code in step (d)(iii).

6. The method of claim 5, further comprising gating off length-16 Walsh covering corresponding to data packets on channels that did not receive a data packet.

7. The method of claim 1, wherein the multi-bit orthogonal code cover distinguishably combines acknowledgment status for data packets received on a multiplicity of different carriers, and also encodes an auxiliary bit for related purposes.

8. The method of claim 7, wherein the auxiliary bit indicates which of a plurality of signal mapping protocols has been applied to generate symbols reflecting acknowledgment status of the different data packets.

9. The method of claim 8, wherein the signal mapping protocols include indicating whether a majority of the data packets were received correctly or incorrectly, and discontinuing transmission for symbols reflecting such majority status for particular data packets, and employing an active symbol to reflect minority status for other particular data packets.

10. The method of claim 3, further comprising selecting the multi-bit orthogonal code for each forward link carrier acknowledgment on a Walsh tree basis such that as the number of forward link carrier data packets to be acknowledged increases, changes between adjacent values of the associated Walsh code cover sequence also increase.

11. The method of claim 3, further comprising selecting between using Walsh code W₄³² and W₁₂³² for the length-32 code of step (c)(iii) depending upon which version of CDMA standard the source station is configured to support.

12. The method of claim 4, wherein the symbol mapping of acknowledgment status of step (c)(i) further includes employing on/off signaling.

13. A method of communicating data asymmetrically between a data source station and a data receiving station, comprising:

a) transmitting a multiplicity of data packets concurrently on a plurality of different channels from the data source station to the data receiving station;

b) receiving the data packets at the receiving station and assigning binary acknowledgment status reflecting reception success or failure of each packet; and

c) transmitting, from the receiving station to the data source station, indications

i) as to whether a majority of the multiplicity of data packets were received correctly; and

ii) reflecting the acknowledgment status of each particular one of the multiplicity of data packets;

d) wherein majority acknowledgment status is indicated by an absence of signal irrespective of whether the majority status is positive or negative acknowledgment.

14. The method of claim 13, further comprising using a joint maximum likelihood algorithm to analyze, at the data source station, the acknowledgment status indicated by the transmission from the data receiving station.

15. A method of asymmetrically receiving data from a particular data source station at a data receiver, comprising:

a) receiving data packets transmitted from the source via a number of different forward link channels that each modulate a corresponding different carrier frequency spectrum;

b) determining a Data Rate Control (DRC) value for each of the different forward link channels;

c) transmitting the DRC value for each of the forward link channels via a reverse link DRC channel modulating a single carrier frequency spectrum, consistently with protocols standardized for a previous version of a CDMA communication system insofar as;

i) the DRC value of each of the forward link channels is reflected in a DRC code sequence based on a 4-bit DRC symbol with biorthogonal encoding and a 3-bit cover,

ii) the reverse link DRC channel carrier frequency has a same relationship to a first one of the forward link channels as in the previous version, and

iii) the reverse link DRC channel is spread using a same length-16 Walsh code as in the previous version; and

d) covering symbol sequences reflecting the DRC value for each of the different forward link carriers with an orthogonal code cover having a length K=2ⁿ, n the smallest integer such that K>

=the number of forward link channels, and combining to form a DRC sequence for spreading as required by step (c)(iii).

16. The method of claim 15, wherein the DRC sequence has a length less than or equal to a length of a standard slot.

17. The method of claim 15, wherein the DRC sequence has a length equal to two or more standard slots.

18. The method of claim 15, further comprising:

e) determining acknowledgment status for each data packet as ACK if it was received correctly, or as NAK if it was received incorrectly; and

f) multiplexing acknowledgment symbols reflecting the different data packets onto the reverse link acknowledgment channel after imposing a corresponding different multi-bit orthogonal code cover on the acknowledgment symbols.

19. The method of claim 15, further comprising gating off the DRC symbol sequence corresponding to each forward link channel for which DRC is unnecessary.

20. A system configured to transmit data asymmetrically, comprising:

a) a data source station configured to concurrently transmit each of a plurality of different data packets in a corresponding different forward link (FL) data channel that modulates a corresponding different FL carrier having a corresponding different frequency spectrum; and

b) a data receiving station including

i) a signal reception module configured to receive the packets transmitted on the plurality of different FL carriers,

ii) a data analysis module configured to determine acknowledgment status for each of the packets and a data rate control (DRC) value for each of the FL data channels,

iii) a DRC signal preparation module configured to establish a symbol sequence that includes the DRC value of each of the FL data channels encoded in a DRC code sequence based on a 4-bit DRC symbol with biorthogonal encoding and a 3-bit cover, and to cover the DRC code sequence for each FL channel with an orthogonal code cover having a length K=2ⁿ, n the smallest integer such that K>

=the number of FL channels, and

iv) a signal transmission module configured to transmit the determined acknowledgment status for the packets and the DRC symbol sequence for the plurality of FL data channels by modulating a single reverse link (RL) carrier having a single frequency spectrum.