Frame structure for an adaptive modulation wireless communication system

• US 9,007,897 B2
• Filed: 08/27/2010
• Issued: 04/14/2015
• Est. Priority Date: 08/03/1999
• Status: Expired due to Fees

• Current Assignee: Quarterhill Inc. (f/k/a Wi-LAN Inc.)
• Original Assignee: Quarterhill Inc. (f/k/a Wi-LAN Inc.)
• Inventors: Klein, Israel Jay, Stanwood, Kenneth L., Pollmann, Steve, Price, Frederick W., Hadar, Rami, Arviv, Eli, Gazelle, David, Gilbert, Sheldon
• Primary Examiner(s): Ngo, Ricky
• Assistant Examiner(s): SAMUEL, DEWANDA A
• Application Number:
  US12/870,620
• Publication Number:
  US 20100323733A1
• Time in Patent Office: 1,691 Days
• Field of Search: 370/329, 370/337, 370/346, 370/347, 370/477, 370/229, 370/442
• US Class Current: 370/229
• CPC Class Codes: H04B 7/2656 for structure of frame, burst
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0004 applied to control information
• CPC Class Codes: H04L 1/0057 Block codes H04L1/0061, H04L1/0064 take precedence
• CPC Class Codes: H04L 1/0059 Convolutional codes
• CPC Class Codes: H04L 1/0065 Serial concatenated codes
• CPC Class Codes: H04L 1/0083 Formatting with frames or packets; Protocol or part of protocol for error control
• CPC Class Codes: H04L 2025/0342 QAM
• CPC Class Codes: H04L 2025/03477 not time-recursive
• CPC Class Codes: H04L 25/03038 with a non-recursive structure H04L25/03031 takes precedence
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A method of simplifying the encoding of a predetermined number of bits of data into frames including adding error coding bits so that a ratio of the frame length times the baud rate of the frame times the bit packing ratio of the data divided the total bits of data is always an integer. The method may also convolutionally encode the bits of data so that the same equation is also always an integer.

Claims

1. A method for transmitting control information in a downlink portion of a data frame between a base station and a plurality of wireless mobile subscriber units over a wireless link, the data frame having a plurality of downlink slots, the method comprising:

determining a respective modulation scheme for wireless mobile subscriber units of the plurality of wireless mobile subscriber units that will receive downlink data in a current data frame, a modulation scheme for a wireless mobile subscriber unit being determined as a function of at least channel interference;

determining the least complex modulation scheme supported by each of the plurality of wireless mobile subscriber units;

identifying a least complex modulation scheme supported by all wireless mobile subscriber units of the plurality of wireless mobile subscriber units to be used for transmitting control information to all of the plurality of wireless mobile subscriber units;

providing control information to be transmitted to all of the plurality of wireless mobile subscriber units, the control information including at least addresses and the modulation schemes determined for the wireless mobile subscriber units of the plurality of wireless mobile subscriber units that will receive downlink data in the current data frame;

modulating the control information using the identified least complex modulation scheme;

modulating data of data blocks to be transmitted to the wireless mobile subscriber units of the plurality of wireless mobile subscriber units that will receive downlink data in the current data frame, using the modulation schemes determined for the wireless mobile subscriber units, and parsing the modulated data of the data blocks into an integer number of downlink slots of the current data frame; and

transmitting the current data frame, including the modulated control information, from the base station to the plurality of wireless mobile subscriber units over the wireless link.

2. A method as claimed in claim 1, wherein identifying the least complex modulation scheme supported by all wireless mobile subscriber units of the plurality of wireless mobile subscriber units is based on the capabilities of the wireless mobile subscriber units.

3. A method as claimed in claim 1, wherein modulating data of data blocks further comprises

encoding data in a data block by selecting a number L of downlink data bits to be parsed into the data block such that a ratio Z between the number of symbols in the current data frame and the number S of symbols in the data block is an integer.

4. A method as claimed in claim 1, wherein a data block is allocated to a wireless mobile subscriber unit based on one or more traffic parameters.

5. A method as claimed in claim 3, wherein encoding data in the data block further comprises adding a number x of error correction bits to a number Ld of user data bits.

6. A method as claimed in claim 5, wherein encoding data in the data block further comprises modulating the Ld+x data bits using the modulation scheme determined for the wireless mobile subscriber unit.

7. A method as claimed in claim 5, wherein a maximum bit per symbol rate (Bi) of the modulation scheme is selected based upon a specified error rate for the transmitted data.

8. A method as claimed in claim 7, wherein Bi is selected as a function of channel interference and implementation complexity of the wireless mobile subscriber unit.

9. A method as claimed in claim 5, wherein encoding data in the data block includes adding forward error correction (FEC) information.

10. A method as claimed in claim 9, wherein encoding data in the data block further includes convolution encoding Ld bits of data using a ratio x/y prior to FEC encoding.

11. A method as claimed in claim 1, further comprising:

providing an unreserved uplink data block for enabling any of the wireless mobile subscriber units to transmit uplink data to the base station; and

modulating the data transmitted by any of the plurality of wireless mobile subscriber units in the unreserved uplink data block using the identified least complex modulation scheme supported by all wireless mobile subscriber units.

18. A method as claimed in claim 1 wherein the control information indicates where modulation transitions occur within the data frame.

19. A method as claimed in claim 18 wherein the data frame is the current data frame.

22. A method as claimed in claim 4, wherein the traffic parameters include a data path quality parameter measured for a data path established between the base station and each wireless mobile subscriber unit.

23. A method as claimed in claim 10, further comprising interleaving the convolutionally encoded data of the downlink data block.

12. A method for wireless transmission of data and control information from a base station to a plurality of wireless mobile subscriber units over a wireless link, the method comprising:

for each wireless mobile subscriber unit of the plurality of wireless mobile subscriber units that will receive downlink data in a current data frame;

assigning a downlink data block in the downlink portion of the current data frame, based on an amount of data awaiting transmission to the wireless mobile subscriber unit,

determining a modulation scheme at least as a function of channel interference, and identifying a number L of data bits to be transmitted in the downlink data block based on the respective modulation scheme,

encoding the data bits to be transmitted in the downlink data block using a number x of error correction bits determined based on the size of the downlink data block, and

parsing the data and error correction bits into the downlink data block;

modulating control information to be transmitted to the plurality of wireless mobile subscriber units using a least complex modulation scheme supported by all of the plurality of wireless mobile subscriber units; and

transmitting the current data frame, including the modulated control information from the base station to the plurality of wireless mobile subscriber units over the wireless link.

13. A method as claimed in claim 12, wherein identifying the least complex modulation scheme available to all of the plurality of wireless mobile subscriber units is based on the capabilities of the wireless mobile subscriber units.

14. A method as claimed in claim 12, wherein determining the modulation scheme for the downlink data block comprises

selecting the number L of downlink data bits including the Ld data bits to be parsed into the downlink data block such that a ratio Z between the number of symbols in the current data frame and the number of symbols in for the data L is an integer.

15. A method as claimed in claim 14, wherein encoding the data bits comprises adding a number x of error correction bits to the Ld data bits.

16. A method as claimed in claim 12 wherein the control information indicates where modulation transitions occur within a data frame.

17. A method as claimed in claim 16 wherein the data frame is the current data frame.

20. A method as claimed in claim 12, wherein the modulation scheme used by the wireless mobile subscriber unit varies as a function of channel interference.

21. A method as claimed in claim 12, wherein the control information is encoded using one of QAM4 and BPSK modulation schemes.