Interference management and handoff techniques

Intersector interference management is crucial in universal frequency reuse systems like OFDMA. In this article, we described advanced interference management techniques for future OFDMA communication systems. Such techniques include dynamic frequency reuse, intersector interference-based power control, and effective intersector handoff using disjoint FL and RL and beacon signaling. Dynamic frequency reuse provides flexible tradeoff between overall capacity and sector edge capacity, resulting in higher sector edge performance and smoother handoff while still keeping the reuse factor close to one. Dynamic frequency reuse scheduling dynamically allocates subcarriers to users for efficient interference control. This article also describes how effective power control can be utilized to tightly manage intersector interference for maintaining system stability in a universal frequency reuse OFDMA system. Transmit power of different ATs is shaped according to the amount of interference they cause to neighbor cells. The proposed handoff algorithm allows fast and seamless intersector handoffs. In addition, two unique techniques are used for enhanced handoff performance and interference reduction. Disjoint links and fast handoff ensure best link performance and minimum interference to other sectors. Beacon signaling is a novel way of transmitting small control messages in an OFDM system. The proposed handoff techniques make use of beacon signaling to transmit pilots in other carrier frequencies, allowing for fast and seamless handoff in a multicarrier deployment and/or an asynchronous deployment, enabling early discovery of neighbor sectors, thereby minimizing handoff delay.