METHODS FOR IMPROVING RANGE FOR MULTICAST WIRELESS COMMUNICATION

• US 20090285146A1
• Filed: 08/04/2009
• Published: 11/19/2009
• Est. Priority Date: 03/01/2002
• Status: Abandoned Application

• Current Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Original Assignee: IPR Licensing Incorporated (InterDigital, Inc.)
• Inventors: Vaidyanathan, Chandra, Sugar, Gary L.
• Application Number:
  US12/535,200
• Publication Number:
  US 20090285146A1
• Time in Patent Office: Days
• US Class Current: 370/312
• CPC Class Codes: H04B 7/0615 of weighted versions of same signal
• CPC Class Codes: H04B 7/0669 using different channel coding between antennas space-time coding H04L1/0618
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• CPC Class Codes: H04B 7/0845 per branch equalization, e.g. by an FIR-filter or RAKE receiver per antenna branch rake receivers as such H04B1/7115
• CPC Class Codes: H04B 7/0854 using error minimizing algorithms, e.g. minimum mean squared error [MMSE], "cross-correlation" or matrix inversion
• CPC Class Codes: H04B 7/0857 using maximum ratio combining techniques, e.g. signal-to- interference ratio [SIR], received signal strenght indication [RSS]
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 2025/03445 Time domain
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

An extended range mode for wireless communication of a multicast data signal from an access point (AP) to multiple stations (STAs) may be enabled or disabled. When the extended range mode is enabled, the AP transmits the data signal up to a total of N times using a transmit delay diversity, where N is the number of transmit antennas.

Claims

1. A method for transmitting a multicast data signal from an access point (AP) having a plurality of N antennas to multiple stations (STAs), comprising:

determining whether an extended range mode is enabled in the AP;

transmitting the data signal once through the N antennas, on a condition that the extended range mode is disabled; and

transmitting the data signal up to a total of N times using transmit delay diversity through the N antennas, on a condition that the extended range mode is enabled.

2. The method as in claim 1, wherein the extended range mode comprises using antenna processing techniques to maximize the range of communication between the AP and the STAS, the antenna processing techniques including composite beamforming.

3. The method as in claim 1, wherein the transmit delay diversity includes a delay between the transmissions of the data among a plurality of AP antennas according to a transmit vector x(t)=[x₀(t), x₁(t−

τ

_D), . . . , x<sub>Nt−

1</sub>(t−

Nt−

1))τ

_D], where τ

_D is a transmit delay parameter.

4. The method as in claim 3, further comprising sending the data signal from each antenna such that the maximum delay spread between any two antennas is (N−

1)τ

_D.

5. An access point (AP) configured to transmit a multicast data signal to multiple stations (STAs), comprising:

a plurality of N antennas;

a processor configured to determine whether an extended range mode is enabled in the AP; and

a transmitter configured to transmit a data signal once through the N antennas on a condition that the extended range mode is disabled, and further configured to transmit the data signal up to a total of N times using transmit delay diversity through the N antennas on a condition that the extended range mode is enabled.

6. The AP as in claim 5, wherein the processor is further configured to execute the extended range mode for the AP using antenna processing techniques to maximize the range of communication between the AP and the STAs, the antenna processing techniques including composite beamforming.

7. The AP as in claim 5, wherein the processor is further configured to determine the transmit delay diversity as a delay between the transmissions of the data among the N antennas according to a transmit vector x(t)=[x₀(t), x₁(t−

τ

_D), . . . , x<sub>Nt−

1</sub>(t−

Nt−

1))τ

_D], where τ

_D is a transmit delay parameter.

8. The AP as in claim 5, wherein the processor is further configured to determine the maximum delay spread between any two antennas as (N−

1)τ

_D.