A novel co-existence algorithm for unlicensed fixed power devices

In the unlicensed spectrum, any device can transmit without a license. Such spectrum has major benefits, but serious challenges must first be overcome. Foremost is the risk of drastic performance degradation due to a lack of incentive to conserve shared resources. Previous work has shown this problem for devices that transmit for longer duration than necessary. This paper demonstrates this problem for devices always transmitting at maximum power to improve the throughput. For devices with fixed transmit powers, the problem is solved if devices defer transmission when the received interference exceeds defined thresholds. We propose a co-existence algorithm designed to optimize system throughput when each of two devices can transmit at the maximum power allowed. We show device performance with current unlicensed band regulations is rarely optimal, and that the proposed algorithm is better.