Framing for an adaptive modulation communication system

• US 8,165,046 B2
• Filed: 02/22/2008
• Issued: 04/24/2012
• Est. Priority Date: 11/15/2000
• 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: Stanwood, Kenneth L., Klein, Israel Jay, Lin, George, Chen, An
• Primary Examiner(s): GREY, CHRISTOPHER P
• Application Number:
  US12/035,549
• Publication Number:
  US 20080144585A1
• Time in Patent Office: 1,523 Days
• Field of Search: 370/276, 370/280, 370/281, 370/294, 370/295, 370/334, 370/345, 370/347, 370/442, 370/503, 370/509, 455/561, 455/562.1
• US Class Current: 370/280
• CPC Class Codes: H04B 7/15557 Selecting relay station operation mode, e.g. between amplify and forward mode, decode and forward mode or FDD - and TDD mode
• CPC Class Codes: H04B 7/212 Time-division multiple access [TDMA]
• CPC Class Codes: H04B 7/2615 using hybrid frequency-time division multiple access [FDMA-TDMA]
• CPC Class Codes: H04B 7/2656 for structure of frame, burst
• CPC Class Codes: H04B 7/2681 Synchronisation of a mobile station with one base station
• 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 5/16 Half-duplex systems; Simplex/duplex switching; Transmission of break signals non-automatically inverting the direction of transmission
• CPC Class Codes: H04W 56/0085 detecting a given structure in the signal
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal

Abstract

A system and method for mapping a combined frequency division duplexing (FDD) Time Division Multiplexing (TDM)/Time Division Multiple Access (TDMA) downlink subframe for use with half-duplex and full-duplex terminals in a communication system. Embodiments of the downlink subframe vary Forward Error Correction (FEC) types for a given modulation scheme as well as support the implementation of a smart antennae at a base station in the communication system. Embodiments of the system are also used in a TDD communication system to support the implementation of smart antennae. A scheduling algorithm allows TDM and TDMA portions of a downlink to efficiently co-exist in the same downlink subframe and simultaneously support full and half-duplex terminals. The algorithm further allows the TDM of multiple terminals in a TDMA burst to minimize the number of map entries in a downlink map. The algorithm limits the number of downlink map entries to not exceed 2n+1, where n is the number of DL PHY modes (modulation/FEC combinations) employed by the communication system.

Claims

1. A base station for wirelessly communicating with a plurality of terminals, comprising:

a transmitter configured to encode data into a downlink sub-frame, and a receiver configured to receive data from an uplink sub-frame, the downlink sub-frame having

control information including a preamble for synchronizing the base station with terminals which are scheduled to receive data in the downlink sub-frame and a frame map which contains information on at least two scheduled events and respective associated, physical (PHY) modes, and

at least two data blocks with downlink data for the scheduled terminals, each data block having a bandwidth allocation in accordance with the frame map and being encoded according to the respective PHY mode; and

an antenna system comprised of smart antennas for transmitting the downlink sub-frame, wherein the downlink data is transmitted to at least one of the scheduled terminals using beam-forming,

wherein the control information is transmitted to the scheduled terminals using a PHY mode which includes a most robust PHY mode compatible with the scheduled terminals.

2. A base station according to claim 1, wherein the smart antennas are configured such that a first smart antenna transmits a first downlink sub-frame, and a second smart antenna transmits a second downlink sub-frame substantially simultaneously.

3. A base station according to claim 1, wherein the frame map comprises a downlink sub-frame map with downlink events for downlink data transmitted to the scheduled terminals and an uplink sub-frame map with uplink events pertaining to terminals scheduled for uplink transmission.

4. A base station according to claim 3, wherein the receiver is configured to decode uplink data received from the terminals scheduled for uplink transmission according to the uplink sub-frame map.

5. A base station according to claim 1, wherein the transmitter is configured to encode the frame map as a TDM signal.

6. A base station according to claim 1, wherein the transmitter is configured to encode the frame map as an OFDM signal.

7. A base station according to claim 1, wherein the at least two data blocks with downlink data are modulated on sub-carriers.

8. A terminal for wirelessly communicating with a base station, comprising:

an antenna system for receiving, from a base station, a downlink sub-frame having

control information including a preamble for synchronizing the terminal with the base station and a frame map with information on scheduled events pertaining to the terminal and respective associated physical (PHY) modes; and

one or more data blocks with downlink data for the terminal, each data block having a bandwidth allocation in accordance with the frame map and being encoded according to the respective PHY mode established for the respective terminal; and

a receiver configured to decode the frame map and to decode downlink data for the terminal from the one or more data blocks ascribed to the terminal, based on the scheduled events provided in the frame map,

wherein the control information is transmitted to the terminal in the downlink sub-frame map using a PHY mode which includes a most robust PHY mode compatible with terminals scheduled to receive data.

9. A terminal according to claim 8, further comprising a transmitter for mapping data to an uplink sub-frame for transmission to the base station.

10. A terminal according to claim 8, wherein the frame map is decoded from a TDM signal.

11. A terminal according to claim 8, wherein the frame map is decoded from an OFDM signal.

12. A terminal according to claim 8, wherein the data blocks are received over sub-carriers assigned to the terminal.

13. A terminal according to claim 8, wherein the terminal is a mobile device.