Abstract: This paper proposes a sectorized distributed antenna system for the orthogonal frequency division multiplexing system in order to both reduce the co-channel interference introduced by frequency reuse and maintain high spectral efficiency. The proposed system is composed of many 120-degree sectorized antennas that are uniformly distributed throughout the whole coverage area. Three adjacent sectors from different antennas share the same frequency band, which can be reused on the adjacent antennas. The new structure provides downlink interference divergence that greatly reduces co-channel interference and improves the system capacity, compared to the traditional cell structure with frequency reuse factor equal to 3. Multiple antennas broadcasting the same signal for a user using the same frequency, known as simulcasting, has been widely studied in distributed antenna systems. However,this paper demonstrates that simulcasting is not suitable for the close interfering structure. Multiple input multiple output distributed antenna systems might be a better choice. 18 Refs. In English.

Key words: Distributed Antenna System; CCI; OFDM; OFDMA