Multi-rate channel design in wireless networks exploiting multi-channel beamforming techniques

The use of multi-beam antennas provides a wireless network node with the capability of concurrent communications with multiple nodes in different directions. Multi-beam antennas have been shown to improve network throughput as well as reliability. In this paper, we consider an array processing based framework in which channel collision is avoided for improved efficiency while interference to ongoing links is tolerable. In particular, new request of communication links is made through a lower-power packet with its data spreading over time. Such service requests can be transmitted any time when the target node is in a receive mode, irrespective to whether the target node is communicating with other nodes or not. Signal spreading ensures that the service request packets do not measurably interfere to the ongoing communication links yet it can be robustly decoded at the target node. The target node will determine the acceptance or denial of a service request based on the request signals.