Antenna sector-time division multiple access system for indoor wireless communications

by Macedo, Aleandro Soares

This thesis proposes a new mvltiple access system for indoor wireless communicatioris based on sectored antennus. Unlike previous sectored ante~a indoor systerns, this system incor- porates the capability of reusing spectrum in different antenna sectors of the base station. It is show that portable terminals located in diaerent sectors of the indoor microcell rnay transmit/receive simultaneous data packets on the same frequency if their mutual inter- ference is below a threshold level that guarantees an acceptable packet error rate. An experiment was devised to rneasm the mutual interference among portables located in some typical indoor environmenks. An algorithm is proposed for scheduling simultaneous padiet transmissions, and its maximum throughput is investigated in the measured indoor locations. Experimental investigation was perfonned using ten sectors; a statistical mode1 is used to investigate different sectorization levels. A new multi-carrier modulation scheme that requires less processing power is proposed, and the system throughput is investigated when operating mith this new scheme and with the conventional multi-carrier scheme. The proposed system can significantly increase capacity when compared with systems that can transmit a single data packet per time slot. For example, while previous systems can tram- mit only one packet at a tirne, the proposed system cas traasmit on average more than four packets per the dot when operating with multi-carrier modulation and ten antenna sectors in an open indoor location. This sâme system configuration can transmit on average close to three packets per time slot in a closed indoor location with interna1 wds of concrete blocks.