Power control of point to multipoint physical channels

Abstract

A method and apparatus are used to determine an efficient transmit power for point to multipoint (PtM) transmissions by maintaining a database at a base station which specifies which of a plurality of wireless transmit/receive units (WTRUs) are members of each PtM group. The transmit power of each WTRU's downlink dedicated channel is adjusted to the minimum required power necessary and the PtM transmit power for each PtM group is set such that the PtM transmit power of a PtM group is equal to the greatest of a WTRU in the PtM group plus a PtM power offset.

What is claimed is: 
     
         1 . A base station configured to transmit point to multipoint (PtM) channels in wireless communications, the base station comprising:
 a receiver configured to receive transmit power control (TPC) commands from a plurality of wireless transmit receive units (WTRUs);   a processor configured to:
 categorize each WTRU of the plurality of WTRUs according to the TPC commands and a database created on the basis of an association of a WTRU with a Ptm channel, wherein the database includes groups of WTRUs from the plurality of WTRUs that are associated with each PtM channel; 
 adjust a transmit power level of a downlink (DL) channel associated with each WTRU of the plurality of WTRUs; 
 set a transmission power level for each of the groups of WTRUs wherein the transmission power level for a PtM channel equals a maximum transmission power level required for a WTRU of the group adjusted by an offset parameter; 
   a PtM transmitter configured to produce a PtM channel with the transmission power level;   an amplifier configured to control the transmission power level of the PtM channel; and   an antenna configured to radiate the PtM channel from a wireless interface.