Methods for improving range for multicast wireless communication

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.

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)=[x 0 (t), x 1 (t−τ D ), . . . , x Nt−1 (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)=[x 0 (t), x 1 (t−τ D ), . . . , x Nt−1 (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 .