BROADCAST SYSTEM INTERFERENCE PROTECTION METHOD AND APPARATUS

• US 20090161608A1
• Filed: 12/21/2007
• Published: 06/25/2009
• Est. Priority Date: 12/21/2007
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Royer, Claude, Steer, David
• Granted Patent: US 8,699,444 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks

Abstract

A method and transceiver in a secondary system for utilizing channel bandwidths allocated to a primary system. A secondary system transceiver receives a primary system signal, re-transmits a delayed version of the primary system signal, and communicates with secondary system equipment utilizing secondary system signals within at least part of a bandwidth of at least one channel of the primary system. The re-transmission of the primary system signal allows the use of primary system channels by the secondary system without adversely affecting the primary or secondary system users.

Claims

1. A method in a secondary system for utilizing channel bandwidths allocated to a primary system, comprising:

in a secondary system transceiver;

receiving a primary system signal;

re-transmitting a delayed version of the primary system signal; and

communicating with secondary system equipment utilizing secondary system signals within at least part of a bandwidth of at least one channel of the primary system.

2. The method of claim 1, further comprising:

fitting a channel plan for the secondary system within at least some of the channel bandwidths of the primary system.

3. The method of claim 1, wherein re-transmitting a delayed version of the primary system signal comprises re-transmitting the delayed version of the primary system signal with a power selected to preserve a signal-to-interference ratio of the primary system signal at primary system receivers.

4. The method of claim 1, wherein timing of the delayed version of the primary system signal is selected to be within multipath delay capability of primary system receivers.

5. The method of claim 1, further comprising:

making use of the received primary system signal to at least partially reduce interference to the secondary system signals.

6. The method of claim 5, wherein making use of the received primary system signal to at least partially reduce interference to the secondary system signals comprises coding the secondary system signals making use of knowledge of the primary system signal.

7. The method of claim 6, wherein coding the secondary system signals comprises coding the secondary system signals using dirty paper coding.

8. The method of claim 1, wherein communicating with secondary service equipment comprises transmitting secondary service signal waveforms that reduce interference to primary system receivers.

9. The method of claim 8, wherein the secondary system signals have symbol rates that are synchronized to a symbol rate of the primary system signal.

10. The method of claim 1, wherein the method is executed in any one of:

a base station and user equipment.

11. The method of claim 10, wherein the user equipment comprises any one of a mobile telephone station, a personal digital assistant, a wireless local area network access point and a wireless-capable personal computer.

12. The method of claim 1, wherein the primary system signal has an orthogonal frequency division multiplexing (OFDM) signal format.

13. The method of claim 12, wherein timing of the delayed version of the primary system signal is selected such that the primary system signal and the re-transmitted delayed version of the primary system signal arrive at primary system receivers within a cyclic prefix interval of the OFDM signal format.

14. The method of claim 12, wherein the OFDM signal format comprises any one of:

Digital Video Broadcast (DVB) signal format, Forward Link Only (FLO) signal format and WiMAX signal format.

15. The method of claim 1, wherein the primary system signal has a single carrier signal format.

16. The method of claim 15, wherein timing of the delayed version of the primary system signal is selected such that the primary system signal and the re-transmitted delayed version of the primary system signal arrive at primary system receivers within an equalizer window.

17. The method of claim 16, wherein the single carrier signal format comprises any one of:

National Television System Committee (NTSC) signal format, Advanced Television System Committee (ATSC) signal format and Advanced Vestigial Side-Band (A-VSB) signal format.

18. The method of claim 1, wherein receiving a primary system signal comprises receiving a plurality of primary system signals, and wherein re-transmitting a delayed version of the primary system signal comprises re-transmitting a delayed version of the plurality of primary system signals.

19. A secondary system transceiver for utilizing in a secondary system channel bandwidths allocated to a primary system, comprising:

a primary system portion that;

receives at least one primary system signal; and

re-transmits a delayed version of the at least one primary system signal; and

a secondary system portion that communicates with secondary system equipment utilizing secondary system signals within at least part of a bandwidth of at least one channel of the primary system.

20. The secondary system transceiver of claim 19, further comprising:

a primary system signal power controller that conditions power level of the at least one primary system signal that is received by the primary system signal receiver such that the re-transmitted delayed version of the at least one primary system signal has a power selected to preserve a signal-to-interference ratio of the at least one primary system signal at primary system receivers.