Adaptive antenna systems and EGPRS data protocol aspects

Antenna systems, which can adapt their radiation pattern dynamically, are often referred to as adaptive antenna systems. By using adaptive antenna systems in a cellular network the interference can be minimized since it is possible to transmit only in the direction of the mobile that needs the information. However, a complication in some packet data networks is that the data packets transmitted on the downlink may contain information intended for two or more mobiles, which might be located in different parts of the cell. An example of this is the data payload and the signaling message for uplink transmission permission in GPRS/EGPRS systems. A number of design concepts that mitigate this transmission direction issue are presented and evaluated in a cellular network simulator. The most promising concept preserves the large system gains from adaptive antenna systems, offering performance within 5 percent of that of an ideal adaptive antenna system without any transmission direction complications.