Efficient multicasting for packet data systems

The invention claims wireless grouping data system in the effective broadcast method and device for. In order to a group of subscriber the broadcast without using single mac id. By using the subscriber group of the channel quality information base station determines with worst channel condition of the subscriber identifier of. And then the multi-point transmission timing and transmission format so as to have worst channel condition of the subscriber can recover transmission. If choosing with worst channel condition of the subscriber of the timing and transmission format is able to the subscriber it also can recover transmission. So it is the single broadcast only need to use the individual mac id and it is not to a plurality of subscriber transmits a plurality of transmission.