WIRELESS DATA COMMUNICATION METHODS AND APPARATUS

• US 20110116569A1
• Filed: 10/05/2010
• Published: 05/19/2011
• Est. Priority Date: 10/05/2009
• Status: Active Grant

• Current Assignee: Simon Fraser University
• Original Assignee: Simon Fraser University
• Inventors: Vanderhelm, Ronald J., Lea, D. Andrew G., Vaughan, Rodney G.
• Granted Patent: US 9,264,111 B2
• Time in Patent Office: Days
• US Class Current: 375/295
• CPC Class Codes: H04B 1/0483 Transmitters with multiple parallel paths
• CPC Class Codes: H04B 7/04 using two or more spaced independent antennas
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04W 72/541 using the level of interference

Abstract

A data communication system has a station that includes multiple antenna elements. The station communicates to the antenna elements by way of digital data channels. Each antenna is connected to an RF module that receives data by way of a corresponding digital data channel, encodes and transmits the data. Adaptive beamforming may be performed for interference mitigation. Embodiments use the strength of pilot signals and/or error vector magnitudes as cost functions for an adaptive beamforming alogorithm such as optimum combining. Unused sub-carriers may be applied to provide in-band communication to facilitate channel switching, data reallocation and other interference mitigation strategies.

Claims

1. A data transmission system comprising a plurality of RF modules each connected to one or more antenna elements, wherein the RF modules are connected to a processor by digital links.

2. A system according to claim 1 wherein the antenna elements are arranged as a random array.

3. A system according to claim 1 wherein the RF modules are each connected to receive an RF carrier reference signal from the processor.

4. A system according to claim 1 configured to add a beacon signal to a transmitted signal in order to facilitate the adaptation of a smart antenna system receiving the transmitted signal.

5. A system according to claim 4 wherein the beacon signal is within a radio frequency bandwidth of the transmitted signal.

6. A system according to claim 4 comprising means for encoding information in the beacon signal.

7. A system according to claim 4 wherein the beacon signal is transmitted on one or more unused sub-carriers (USCs) in an OFDM scheme.

8. A system according to claim 4 wherein the beacon signal is added using digital signal processing capability in the RF modules.

9. A system according to claim 1 wherein the RF modules are arranged to provide a classical pattern beamforming array.

10. A system according to claim 1 comprising an adaptive antenna processor wherein the adaptive antenna processor is configured to control an antenna pattern by one or more of:

selecting from among a plurality of configurations of the antenna elements having corresponding directional patterns;

controlling amplitudes and/or phases of signals provided to and/or received at different ones of the antenna elements;

selecting among different sub-sets of the antenna elements;

altering positions orientations and/or configurations of one or more of the antenna elements.

11. A system according to claim 1 wherein the digital data links are wireless links.

12. A system according to claim 1 comprising an adaptive antenna processor configured to perform adaptive beamforming.

13. A data communication system according to claim 12 wherein at least some processing for the adaptive beamforming is provided by the RF modules.

14. A system according to claim 12 wherein the adaptive beamforming implements an optimal combining algorithm.

15. A data communication system according to claim 12 wherein the adaptive beamforming is performed in response to a cost function.

16. A system according to claim 13 wherein the cost function comprises a signal proportional to the strength of a signal being received.

17. A data communication system according to claim 13 wherein the cost function comprises a measure of one or more beacon signals appended to the received signal, or error vector magnitudes from the detection of the wanted signals, or a combination of these.

18. A system according to claim 15 wherein the cost function comprises a measure of one or more pilot signals carried on one or more unused sub-carriers within the signal spectrum of an OFDM signal.

19. A system according to claim 15 wherein the cost function comprises a measure of a beacon signal that is unique to a user such that signals which include a beacon signal of one user can be distinguished from other signals.

20. A system according to claim 15 wherein the cost function comprises a measure of a beacon signal and the beacon signal carries in-band control signals for antenna adaptation.

22. An adapter according to claim 19 wherein the adapter is configured to reassign data in an OFDM signal received from the antenna system on one or more sub-carriers of the received OFDM signal to other sub-carriers before passing the OFDM signal to the OFDM radio.

21. An adapter for use between an OFDM radio and an antenna system, the adapter comprising an OFDM demodulator a multiplexer and an OFDM modulator, the adapter configured to reassign data in an OFDM signal received from the OFDM radio on one or more sub-carriers of the received OFDM signal to other sub-carriers before passing the OFDM signal to an antenna system.