Mitigation of wireless transmit/receive unit (WTRU) to WTRU interference using multiple antennas or beams

• US 7,630,688 B2
• Filed: 12/29/2004
• Issued: 12/08/2009
• Est. Priority Date: 03/31/2004
• Status: Active Grant

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Zeira, Eldad
• Primary Examiner(s): Nguyen; Duc
• Assistant Examiner(s): Rego; Dominic E
• Application Number:
  US11/025,252
• Publication Number:
  US 20050221861A1
• Time in Patent Office: 1,805 Days
• Field of Search: 455/562.1, 455/63.1, 455/114.1, 455/278.1, 455/296, 455/67.13, 455/135, 455/161.3, 455/277.2, 455/13.3, 455/25, 455/63.4, 455/82, 455/575.7, 370/310, 370/328, 370/330, 370/332
• US Class Current: 455/63.1
• CPC Class Codes: H04B 7/0408 using two or more beams, i.e. beam diversity
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0695 using beam selection
• CPC Class Codes: H04B 7/088 using beam selection
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

Multiple antenna elements of a WTRU are used to form an adaptive antenna beam pattern for receiving signals in the downlink direction. The WTRU utilizes the formed antenna beam to form a transmission antenna beam for transmitting signals in the uplink direction. In an alternate embodiment, the multiple antenna elements are used to form a plurality of fixed, predetermined antenna beams. The WTRU then selects and switches to the one of the predetermined beams that yields the best downlink reception signals. The WTRU utilizes the selected beam pattern to transmit signals in the uplink direction. In an alternate embodiment, the WTRU receives spectral arrangement information and utilizing this information to avoid transmitting in the direction of spectrally adjacent WTRUs.

Claims

1. A method for mitigating wireless transmit/receive unit (WTRU) to WTRU interference in wireless communications, the method comprising:

monitoring received signals at a WTRU including a downlink (DL) communication signal and an interfering uplink (UL) communication signal from another WTRU;

determining a signal quality of the DL communication signal;

calculating reception antenna weights based on the signal quality;

forming a directed antenna beam for receiving signals based on the reception antenna weights such that a reception beam is directed toward a source of the received DL communication signal and a null beam is directed toward a source of the interfering UL communication signal;

deriving transmission antenna weights from the reception antenna weights; and

forming a directed transmission beam for transmitting UL signals based on the derived transmission antenna weights.

2. The method of claim 1 wherein the transmission antenna weights are derived to be equal to the reception antenna weights.

3. The method of claim 1 further comprising dynamically adapting the formed antenna beams to current radio conditions.

4. The method of claim 1 wherein the reception antenna weights are calculated to increase signal-to-noise ratio (SNR) or signal-to-noise plus interference ratio (SNIR).

5. The method of claim 1 wherein the reception antenna weights are calculated to reduce received interference.

6. The method of claim 1 wherein the reception antenna weights are calculated to reduce received interference while maintaining a constant received signal level of the DL communications signal.

7. The method of claim 1 further comprising directing multiple nulls in directions other than that of the source of the DL communications signal.

8. A wireless transmit/receive unit (WTRU) comprising:

an antenna array configured to receive signals including a downlink (DL) communication signal and an interfering uplink (UL) communication signal from another WTRU;

a signal processing unit configured to determine a signal quality of the DL communication signal and calculate reception antenna weights based on the signal quality;

the antenna array operatively associated with a signal weighting unit to form a directed antenna beam for receiving downlink (DL) signals based on the reception antenna weights such that a reception beam is directed toward a source of the received DL communication signal and a null beam is directed toward a source of the interfering UL communication signal;

the signal processing unit configured to derive transmission antenna weights from the reception antenna weights; and

the antenna array operatively associated with the signal weighting unit to form a directed transmission beam for transmitting uplink (UL) signals based on the transmission antenna weights.

9. The WTRU of claim 8 wherein the signal processing unit is configured to derive the transmission antenna weights to be equal to the reception antenna weights.

10. The WTRU of claim 8 wherein the signal processing unit, the antenna array, and the signal weighting unit are configured to dynamically adapt the formed antenna beams to current radio conditions.

11. The WTRU of claim 8 wherein the signal processing unit is configured to calculate the reception antenna weights to increase signal-to-noise ratio (SNR) or signal-to-noise plus interference ratio (SNIR).

12. The WTRU of claim 8 wherein the signal processing unit is configured to calculate the reception antenna weights to reduce received interference.

13. The WTRU of claim 8 wherein the signal processing unit is configured to calculate the reception antenna weights to reduce received interference while maintaining a constant received signal level of the DL communications signal.

14. The WTRU of claim 8 wherein the antenna array is operatively associated with the signal weighting unit to form the directed antenna beam such that multiple nulls are directed in directions other than towards the source of the DL communications signal.