In conventional digital cellular mobile radio communication systems a mobile station communicates with only one base station at each given time. However, recently it has been suggested to use so called macro diversity in such systems. This concept means that in the down link direction several base stations send the same information blocks to a mobile station, which combines the sent blocks into a final received block. In the up link direction a mobile station transmits an information block which is received at several base stations. The received blocks are transmitted to a common node in the land system, for example a mobile services switching center, where the received blocks are combined into a final received block. These procedures increase the reliability of the received information blocks, since the information has now travelled along different paths, one of which may distort the information less than the other.
A drawback of these up link diversity methods is that the received information blocks from several base stations have to be sent to the mobile services switching center, which reduces the capacity of the land system.