System and method of dynamically optimizing a transmission mode of wirelessly transmitted information

• US 6,802,035 B2
• Filed: 04/01/2002
• Issued: 10/05/2004
• Est. Priority Date: 09/19/2000
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Intel Corporation
• Inventors: Airy, Manish, Catreux, Severine, Gesbert, David
• Primary Examiner(s): MOISE, EMMANUEL LIONEL
• Application Number:
  US10/072,359
• Publication Number:
  US 20020147953A1
• Time in Patent Office: 918 Days
• Field of Search: 714/746, 714/704, 714/708, 714/748, 714/751, 714/776, 370/252, 370/345, 370/206, 375/259, 375/261, 375/267, 455/102
• US Class Current: 714/746
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0016 involving special memory structures, e.g. look-up tables
• CPC Class Codes: H04L 1/0021 in which the algorithm uses adaptive thresholds
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0033 arrangements specific to the transmitter
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 1/20 using signal quality detector
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365

Abstract

The present invention includes a method of optimizing a transmission mode of wirelessly transmitted data. The method includes selecting a first transmission mode based on a predetermined channel database and a first channel characterization. The first channel characterization can be based upon signals transmitted in an initial mode. An error factor is generated based on a difference between an estimated performance characteristic, and an expected performance characteristic. A subsequent transmission mode is selected based upon the predetermined channel database, the error factor and a subsequent channel characterization. The predetermined channel database can include a predetermined look-up-table that provides transmission mode selections based upon the channel characterizations. The look-up-table generally includes a plurality of quality parameter thresholds that determine the selection of a transmission mode. Another method includes receiving transmission signals that include data encoded in an initial transmission mode. A first quality parameter of the received transmission signals is measured. A subsequent transmission mode is selected based upon the quality parameter. Transmission signals are received having data encoded in the subsequent transmission mode. A second quality parameter is measured. A parameter is adjusted within selection criteria of another subsequent transmission mode based upon the second quality parameter.

Claims

1. A method of optimizing a transmission mode of wirelessly transmitted data, the method comprising:

selecting a first transmission mode based on a predetermined channel database and a first channel characterization;

generating an error factor based on a difference between an estimated performance characteristic of data signals transmitted according to the first transmission mode, and an expected performance characteristic of data signals transmitted according to the first transmission mode; and

selecting a subsequent transmission mode based upon the predetermined channel database, the error factor and a subsequent channel characterization.

2. The method of optimizing a transmission mode of wirelessly transmitted data of claim 1, wherein the first channel characterization is based upon signals transmitted in an initial mode.

3. The method of optimizing a transmission mode of wirelessly transmitted data of claim 1, wherein the predetermined channel database comprises a predetermined lookup-table that provides a transmission mode selection based upon a channel characterization.

4. The method of optimizing a transmission mode of wirelessly transmitted data of claim 3, wherein the look-up-table comprises a plurality of quality parameter thresholds that determine the selection of a transmission mode.

5. The method of optimizing a transmission mode of wirelessly transmitted data of claim 4, wherein selecting a subsequent transmission mode based upon the predetermined channel database, the error factor, and a subsequent channel characterization comprises:

adjusting the quality parameter thresholds within the predetermined look-up-table with the error factor; and

selecting the subsequent transmission mode based upon the adjusted look-up-table and the subsequent channel characterization.

6. The method of optimizing a transmission mode of wirelessly transmitted data of claim 1, wherein the error factor is generated once for every received data packet.

7. The method of optimizing a transmission mode of wirelessly transmitted data of claim 6, wherein the error factor is set to a first value if a data packet is properly received, and the error factor is set to a second value f the data packet is improperly received.

8. The method of optimizing a transmission mode of wirelessly transmitted data of claim 6, wherein the quality parameter thresholds within the predetermined look-up-table are adjusted by the error factor after the reception of each data packet.

9. The method of optimizing a transmission mode of wirelessly transmitted data of claim 1, wherein the error factor is generated once per a predetermined amount of time.

10. The method of optimizing a transmission mode of wirelessly transmitted data of claim 9, wherein the error factor is set to a first value if an average packet error rate is greater than an upper bound threshold, and the error factor is set to a second value if the average packet error rate is less than an lower bound threshold.

11. The method of optimizing a transmission mode of wirelessly transmitted data of claim 3, wherein the selecting a subsequent transmission mode based upon the predetermined channel database, the error factor and a subsequent channel characterization comprises:

adjusting the subsequent channel characterization with the error factor;

x and

selecting the subsequent transmission mode based upon the look-up-table and the adjusted subsequent channel characterization.

12. The method of optimizing a transmission mode of wirelessly transmitted data of claim 1, further comprising:

individually selecting a first transmission mode based on a predetermined channel database and a first channel characterization for each of a plurality of transmission streams, each of the plurality of transmission streams being received by the same receiver, allowing spatial multiplexing;

generating an error factor based on a difference between an estimated performance characteristic, and an expected performance characteristic, for the plurality of transmission streams; and

selecting a subsequent transmission mode based upon the predetermined channel database, the error factor and a subsequent channel characterization, for the transmission streams.

13. The method of optimizing a transmission mode of wirelessly transmitted data of claim 12, wherein the transmission streams are transmitted from a plurality of base stations.

14. The method of optimizing a transmission mode of wirelessly transmitted data of claim 13, wherein an error factor is selected for each base station.

15. The method of optimizing a transmission mode of wirelessly transmitted data of claim 13, wherein, a subsequent transmission mode is selected for each of the transmission streams.

16. A method of optimizing a transmission mode of wirelessly transmitted data, the method comprising:

receiving transmission signals that include data encoded in an initial transmission mode;

measuring a first quality parameter of the received transmission signals;

selecting a subsequent transmission mode based upon the quality parameter;

receiving transmission signals having data encoded in the subsequent transmission mode;

measuring a second quality parameter; and

adjusting a parameter within selection criteria of another subsequent transmission mode based upon the second quality parameter.

17. The method of optimizing a transmission mode of wirelessly transmitted data of claim 16, wherein selecting a subsequent transmission mode based upon the quality parameter comprises referencing a predetermined look-up-table that provides a subsequent transmission mode selection based upon the first quality parameter.

18. The method of optimizing a transmission mode of wirelessly transmitted data of claim 17, wherein the look-up-table comprises a plurality of quality parameter thresholds that determine the selection of a subsequent transmission mode.

19. The method of optimizing a transmission mode of wirelessly transmitted data of claim 18, wherein adjusting a parameter within a selection criteria of the subsequent transmission mode based upon the second quality parameter comprises:

adjusting the quality parameter thresholds within the predetermined look-up-table.

20. The method of optimizing a transmission mode of wirelessly transmitted data of claim 18, wherein the second quality parameter is obtained once for every received data packet.

21. The method of optimizing a transmission mode of wirelessly transmitted data of claim 20, wherein obtaining the second quality parameter comprises incrementing a table correction factor by a first value if a data packet is properly received, and incrementing the table correction factor by a second value if the data packet is improperly received.

22. The method of optimizing a transmission mode of wirelessly transmitted data of claim 21, wherein the quality parameter thresholds within the predetermined look-up-table are adjusted by the table correction factor after the reception of each data packet.

23. The method of optimizing a transmission mode of wirelessly transmitted data of claim 21, wherein a magnitude of the first value and a magnitude of a second value are dependent upon a convergence time.

24. The method of optimizing a transmission mode of wirelessly transmitted data of claim 16, wherein a subsequent transmission mode based upon the quality parameter is periodically selected.

25. The method of optimizing a transmission mode of wirelessly transmitted data of claim 16, wherein adjusting a parameter within a selection criteria of the subsequent transmission mode based upon the second quality parameter comprises:

adjusting a value of the first quality parameter before referencing the predetermined look-up-table.

26. A method of optimizing a transmission mode of wirelessly transmitted data, the method comprising:

receiving a data signal from a transmitter, data of the data signal arranged according to a first transmission mode based on a predetermined channel database and a first channel characterization;

generating an error factor based on a difference between an estimated performance characteristic of the received data signal, and an expected performance characteristic of the received data signal; and

aiding in selection of a subsequent transmission mode based upon the predetermined channel database, the error factor and a subsequent channel characterization.

27. A method of optimizing a transmission mode of wirelessly transmitted data, the method comprising:

transmitting a data signal from a transmitter, data of the data signal arranged according to an initial transmission mode based on a predetermined channel database and an initial channel characterization;

the transmitter receiving an error factor based on a difference between an estimated performance characteristic of the transmitted data signal, and an expected performance characteristic of the transmitted data signal; and

selecting a subsequent transmission mode based upon the predetermined channel database, the error factor and a subsequent channel characterization.

28. A method for dynamically adjusting a transmission mode, the method comprising:

generating an error factor associated with the difference between an estimated performance characteristic of data signals transmitted according to a first transmission mode, and an expected performance characteristic of data signals transmitted according to the first transmission mode; and

selecting a subsequent transmission mode based, at least in part, on a channel database and the generated error factor.

29. A method according to claim 28, wherein the channel database comprises a lookup table that provides a number of transmission modes indexed, at least in part, by channel characterization.

30. A method according to claim 28, the element of selecting a subsequent transmission mode comprising:

adjusting one or more quality parameter thresholds in the lookup table based, at least in part, on the generated error factor; and

selecting the subsequent transmission mode based upon the adjusted lookup table and subsequent channel characterization.

31. A receiver comprising:

a storage medium to store executable content; and

control logic, coupled with the storage medium to selectively execute at least a subset of the executable content to generate an error factor associated with the difference between an estimated performance characteristic of data signals transmitted according to a first transmission mode, and an expected performance characteristic of data signals transmitted according to the first transmission mode, and to select a subsequent transmission mode based, at least in part, on a channel database and the generated error factor.

32. A transmitter comprising:

a controller, to apply a select transmission mode to a wireless transmission of information; and

a mode selection unit, coupled to the controller, to receive an indication of an error factor based, at least in part, on a difference between an estimated performance characteristic of data signals transmitted according to a prior transmission mode, and an expected performance characteristic of data signals transmitted according to the prior transmission mode, and to select a subsequent transmission mode based upon the predetermined channel database, the error factor and a subsequent channel characterization.

33. A transmitter according to claim 32, further comprising:

a transmit processing unit, coupled to the controller, to receive the select transmission mode and apply it to received information for wireless transmission.

34. A transmitter according to claim 33, further comprising:

a spatial mapping element, coupled to the controller, to receive the select transmission mode and selectively apply a spatial processing to information received from the transmit processing unit.

35. A transmitter according to claim 34, further comprising:

a radio frequency (RF) amplification stage, coupled with the spatial mapping unit, to receive information processed with the select transmission mode and generate a wireless transmission signal for transmission via one or more antenna(e).

36. A transmitter according to claim 32, wherein the transmission mode is comprised of one or more of a modulation rate, a coding rate, and a spatial transmission mode.

37. A transmitter according to claim 32, wherein the indication of an error factor is received from a remote receiver.

38. A transmitter according to claim 32, wherein the indication of an error factor is received from a receiver co-located with the transmitter.

39. A wireless communication device comprising:

one or more omnidirectional antenna(e); and

a transmitter, selectively coupled with at least a subset of the one or more omnidirectional antennae, to generate a wireless transmission signal, the transmitter including a controller, to apply a select transmission mode to a wireless transmission of information, and a mode selection unit, coupled to the controller, to receive an indication of an error factor based, at least in part, on a difference between an estimated performance characteristic of data signals transmitted according to a prior transmission mode, and an expected performance characteristic of data signals transmitted according to the prior transmission mode, and to select a subsequent transmission mode based upon the predetermined channel database, the error factor and a subsequent channel characterization.