An ON-OFF Synchronous Sectored Operation for Packet Data Transmission in Cellular Systems

In this paper, the throughput maximization and fairness problems in the downlink of a sectorized CDMA cellular system are studied. We focus in maximizing the data rate for users on the cell border. An optimum data transmission with power control allocates the maximum allowable rate to only one user with the highest SINR. However, this throughput maximizing rate allocation strategy causes high unfairness. On the other hand, if more service time or slots are assigned to the lower SINR users for fairness, system throughput will be decreased. Thus, we propose the operation of a system in a four time interval duty cycle that increases system throughput and fairness at the same time. In the first interval, users close to the base stations are served, one at a time in every sector. In the rest of the time intervals, for users close to the cell border, an ON-OFF synchronous sectored operation is achieved. In this operation only one sector of each cell is allowed to transmit per each interval to only one user. The results show that the average data rate at the cell border is increased 130% relative to the traditional one-by-one transmission in each sector. On the other hand, the average data rate over the sector area is increased 13-27% depending on the required quality of service.