Method and apparatus for receiving data in a wireless communications system

• US 20020145985A1
• Filed: 02/06/2002
• Published: 10/10/2002
• Est. Priority Date: 02/07/2001
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Love, Robert T., Classon, Brian K., Cudak, Mark C., Nikides, Robert S., Jalloul, Louay A.
• Granted Patent: US 7,158,482 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04L 1/1845 Combining techniques, e.g. code combining
• CPC Class Codes: H04L 12/56 Packet switching systems
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 92/10 between terminal device and access point, i.e. wireless air interface

Abstract

A communication system includes a forward link from a base station to multiple mobile units, the forward link having multiple shared channels (SHCH'"'"'s), multiple shared control channels (SHCCH'"'"'s), and multiple dedicated pointer control channels (DPTRCH'"'"'s), and utilizes HARQ error control for error detection and error correction. The mobile unit, when listening to the DPTRCH, uses a SHCCH pointed to by the DPTRCH to demodulate and decode data on the SHCH. Throughput problems may arise in the system when the mobile unit combines and decodes the wrong SHCH data, that is, SHCH data that is intended for a different mobile unit, or may incorrectly decodes SHCH data that is intended for the mobile unit. In order to improve the data throughput of the system, the systems employs a flush test and an energy detector test to prevent improperly decoded data blocks from corrupting properly decoded data blocks.

Claims

1. A method for receiving data in a wireless communication system comprising steps of:

receiving shared channel data over a shared channel;

storing the received shared channel data to produce stored shared channel data;

receiving shared control channel data over a shared control channel;

decoding the received shared control channel data to produce decoded shared control channel data;

determining whether the decoded shared control channel data differs from previously received shared control channel data; and

when the decoded shared control channel data differs from previously received shared control channel data, dispensing with at least one of the decoded shared control channel data and the stored shared channel data.

2. The method of claim 1, wherein the step of determining whether the decoded shared control channel data differs from previously received shared control channel data comprises a step of:

determining whether a decoding error has occurred with respect to the decoded shared control channel data; and

when no decoding error is determined to have occurred with respect to the decoded shared control channel data, determining whether the decoded shared control channel data differs from previously received shared control channel data.

3. The method of claim 2, further comprising steps of:

when a decoding error is determined to have occurred with respect to the received shared control channel data, performing an error detection test on the received shared control channel data;

when the error detection test detects an error, ignoring the received shared control channel data.

4. The method of claim 1, wherein the step of determining whether the decoded shared control channel data differs from previously received shared control channel data comprises a step of determining whether the decoded shared control channel data differs from previously received shared control channel data in a manner inconsistent with a protocol causing a protocol error.

5. The method of claim 1, wherein the data received over the shared control channel comprises a frame, wherein the step of determining whether the decoded shared control channel data differs from previously received shared control channel data comprises a step of determining whether the decoded shared control channel frame differs from a previously received shared control channel frame, and wherein the step of dispensing comprises a step of, when the decoded shared control channel frame differs from a previously received shared control channel frame, purging the stored shared channel data.

6. The method of claim 1, wherein the data received over the shared control channel comprises a frame, wherein the step of determining whether the decoded shared control channel data differs from previously received shared control channel data comprises a step of determining whether the decoded shared control channel frame differs from one or more frames of a plurality of previously received shared control channel frames, and wherein the step of dispensing comprises a step of, when the decoded shared control channel frame differs from the one or more frames of the plurality of previously received shared control channel frames, ignoring the decoded shared control channel frame.

7. The method of claim 1, wherein the step of receiving data over a shared control channel comprises a step of receiving each of a first frame and a second frame over a shared control channel, wherein the step of decoding the received shared control channel data comprises steps of decoding the first frame to produce a decoded first frame and decoding the second frame to produce a decoded second frame, wherein the step of determining whether the decoded shared control channel data differs from previously received shared control channel data comprises steps of:

comparing the decoded first frame to the decoded second frame to produce a comparison;

determining whether the decoded first frame differs from the decoded second frame;

when the decoded first frame differs from the decoded second frame but each of the decoded first frame and the decoded second frame appears to correspond to a same data packet, performing steps of;

computing a first energy level for the first frame;

computing a second energy level for the second frame;

comparing the first energy level to the second energy level to produce a comparison; and

wherein the step of dispensing comprises a step of ignoring one of the decoded first frame and the decoded second frame based on the comparison.

8. The method of claim 1, wherein the method further comprises steps of:

receiving dedicated pointer channel data over a dedicated pointer channel, wherein the dedicated pointer channel data comprises a plurality of dedicated pointer channel frames;

when the decoded shared control channel data differs from previously received shared control channel data;

computing a first energy level for a first dedicated pointer channel frame of the plurality of dedicated pointer channel frames;

computing a second energy level for a second dedicated pointer channel frames of the plurality of dedicated pointer channel frames;

comparing the first energy level to the second energy level to produce an energy metric;

comparing the energy metric to a threshold; and

ignoring the dedicated pointer channel when the energy metric compares unfavorably with the threshold.

9. The method of claim 1, wherein the method further comprises steps of:

receiving dedicated pointer channel data over a dedicated pointer channel data, wherein the dedicated pointer channel comprises a plurality of data fields and points to the shared control channel;

when the decoded shared control channel data differs from previously received shared control channel data;

computing a first energy level for a first data field of the plurality of data fields;

computing a second energy level for a second data field of the plurality of data fields;

comparing the first energy level to the second energy level produce an energy metric;

comparing the energy metric to a threshold; and

ceasing decoding of data received over at least one of the shared control channel and the shared channel when the energy metric compares unfavorably with the threshold.

10. A method for receiving data in a wireless communication system comprising steps of:

receiving data over a control channel to produce received data;

determining an energy metric for the received data;

comparing the determined energy metric to a threshold; and

ignoring the received data when the energy metric compares unfavorably with the threshold.

11. The method of claim 10, wherein the received data comprises a frame and wherein the step of determining an energy metric comprises a step of computing an energy corresponding to a data field of the frame.

12. The method of claim 11, wherein the control channel is a dedicated pointer control channel and the data field comprises a pointer bit field of a frame received over the dedicated pointer control channel.

13. The method of claim 10, wherein the control channel is a dedicated pointer control channel, wherein the received data comprises a frame having a plurality of data fields that is received over the dedicated pointer control channel, and wherein the step of determining an energy metric comprises steps of:

determining a first energy level of a first data field of the plurality of data fields and a second energy level of a second data field of the plurality of data fields; and

comparing the first energy level to the second energy level to produce an energy metric.

14. The method of claim 13, wherein the first data field is a power control bit field and the second data field is a pointer bit field.

15. The method of claim 10, wherein the step of receiving data over a control channel comprises steps of receiving shared control channel data over a shared control channel and receiving dedicated pointer control channel data over a dedicated pointer control channel, and wherein the step of determining an energy metric for the received data comprises steps of:

determining a first energy level corresponding to the received shared control channel data;

determining a second energy level corresponding to the received dedicated pointer control channel data; and

comparing the first energy level to the second energy level to produce an energy metric; and

wherein the step of ignoring the received data when the energy metric compares unfavorably with the threshold comprises a step of ignoring the dedicated pointer control channel data when the energy metric compares unfavorably with the threshold.

16. The method of claim 15, further comprising a step of ceasing decoding of data received over at least one of the shared control channel and the shared channel when the energy metric compares unfavorably with the threshold.

17. The method of claim 10, wherein the control channel is a shared control channel and wherein the received data comprises shared control channel data, wherein the method further comprises a step of receiving shared channel data over a shared channel, and wherein the step of determining an energy metric for the received data comprises steps of:

determining a first energy level corresponding to the received shared control channel data;

determining a second energy level corresponding to the received shared channel data; and

comparing the first energy level to the second energy level to produce an energy metric; and

wherein the step of ignoring the received data when the energy metric compares unfavorably with the threshold comprises a step of ignoring the shared control channel data when the energy metric compares unfavorably with the threshold.

18. The method of claim 17, further comprising a step of ceasing decoding of data received over the shared channel when the energy metric compares unfavorably with the threshold.

19. The method of claim 10, wherein the control channel is a shared control channel.

20. A communication device comprising:

a receiver that receives shared control channel data over a shared control channel and shared channel data over a shared channel;

a memory that stores previously received shared control channel data and further stores previously received shared channel data to produce stored shared channel data; and

a processor operably coupled to each of the receiver and the memory that decodes the received shared control channel data to produce decoded shared control channel data, determines whether the decoded shared control channel data differs from previously received shared control channel data, and when the decoded shared control channel data differs from previously received shared control channel data, dispenses with at least one of the decoded shared control channel data and the stored shared channel data.

21. The communication device of claim 20, wherein the data received over the shared control channel comprises a shared control channel frame, wherein the determination, by the processor, of whether the decoded shared control channel data differs from previously received shared control channel data comprises determining whether the decoded shared control channel frame differs from a previously received shared control channel frame, and wherein the processor purges the stored shared channel data when the decoded shared control channel frame differs from a previously received shared control channel frame.

22. The method of claim 20, wherein the data received over the shared control channel comprises a shared control channel frame, wherein the determination, by the processor, of whether the decoded shared control channel data differs from previously received shared control channel data comprises determining whether the decoded shared control channel frame differs from one or more frames of a plurality of previously received shared control channel frames, and wherein the processor ignores the decoded shared control channel frame when the decoded shared control channel frame differs from the one or more frames of the plurality of previously received shared control channel frames.

23. The communication device of claim 20, wherein the reception, by the receiver, of data over a shared control channel comprises receiving each of a first frame and a second frame over a shared control channel, wherein decoding, by the processor, of the received shared control channel data comprises decoding the first frame to produce a decoded first frame and decoding the second frame to produce a decoded second frame, and wherein the determination, by the processor, of whether the decoded shared control channel data differs from previously received shared control channel data comprises comparing the decoded first frame to the decoded second frame to produce a comparison, determining whether the decoded first frame differs from the decoded second frame, and when the decoded first frame differs from the decoded second frame but each of the decoded first frame and the decoded second frame appears to correspond to a same data packet, computing a first energy level for the first frame, computing a second energy level for the second frame, comparing the first energy level to the second energy level to produce a comparison, and wherein the processor ignores one of the decoded first frame and the decoded second frame based on the comparison.

24. The communication device of claim 20, wherein the receiver further receives dedicated pointer channel data over a dedicated pointer channel, wherein the dedicated pointer channel data comprises a plurality of dedicated pointer channel frames, and, wherein the processor, when the decoded shared control channel data differs from previously received shared control channel data, further computes a first energy level for a first dedicated pointer channel frame of the plurality of dedicated pointer channel frames computes a second energy level for a second dedicated pointer channel frame of the plurality of dedicated pointer channel frames, compares the first energy level to the second energy level to produce an energy metric, compares the energy metric to a threshold, and ignores the dedicated pointer channel when the energy metric compares unfavorably with the threshold.

25. The communication device of claim 20, wherein the receiver further receives dedicated pointer channel data over a dedicated pointer channel, wherein the dedicated pointer channel data comprises a plurality of data fields and points to the shared control channel, and wherein the processor, when the decoded shared control channel data differs from previously received shared control channel data, further computes a first energy level for a first data field of the plurality of data fields, computes a second energy level for a second data field of the plurality of data fields, compares the first energy level to the second energy level to produce an energy metric, compares the energy metric to a threshold, and ceases decoding of data received over at least one of the shared control channel and the shared channel when the energy metric compares unfavorably with the threshold.

27. The communication device of claim 26, wherein the receiver receives shared control channel data over a shared control channel and receives dedicated pointer control channel data over a dedicated pointer control channel, and wherein the determination, by the processor, of an energy metric for the received data comprises determining a first energy level corresponding to the received shared control channel data, determining a second energy level corresponding to the received dedicated pointer control channel data, and comparing the first energy level to the second energy level to produce an energy metric, and wherein the processor ignores the dedicated pointer control channel data when the energy metric compares unfavorably with the threshold.

28. The communication device of claim 27, wherein the processor further ceases decoding data received over at least one of the shared control channel and the shared channel when the energy metric compares unfavorably with the threshold.

29. The communication device of claim 26, wherein the control channel is a shared control channel and wherein the received data comprises shared control channel data, wherein the receiver further receives shared channel data over a shared channel, and wherein the determination, by the processor, of an energy metric for the received data comprises determining a first energy level corresponding to the received shared control channel data, determining a second energy level corresponding to the received shared channel data, and comparing the first energy level to the second energy level to produce an energy metric, and wherein the processor ignores the shared control channel data when the energy metric compares unfavorably with the threshold.

30. The communication device of claim 29, wherein the processor further ceases decoding data received over the shared channel when the energy metric compares unfavorably with the threshold.

26. A communication device comprising:

a receiver that receives data over a control channel to produce received data; and

a processor operably coupled to the receiver that determines an energy metric for the received data, compares the determined energy metric to a threshold, and ignores the received data when the energy metric compares unfavorably with the threshold.