Method and apparatus for maintaining a predefined transmission quality in a wireless network for a metropolitan area

Abstract

A technique for maintaining a predefined transmission quality in a wireless Metropolitan Area Network (MAN). Each of a plurality of Local Area Networks are coupled to a corresponding router. Each router is coupled to one or more transceivers for interconnecting the routers via wireless links. Each router stores a table representative of the topology of the MAN and receives detected indicia representative of the quality of the wireless links and representative of network traffic loads. The router adapts the manner of transmission and the path of transmission according to the indicia. As a result, the MAN is highly efficient, in terms of cost, power and bandwidth utilization. For example, a strength of a signal received over a wireless communication link is periodically monitored for maintaining the strength within a predefined range by adjusting the transmission power. In addition, an error rate for the data received over the link is monitored. If the received signal strength remains below the predefined range despite the transmit power having been adjusted to a maximum allowable level, and if the error rate approaches a predefined limit, one or more techniques are selectively employed to reduce the error rate while maintaining a sufficiently high network throughput. The adaptive techniques include changing the data rate, modulation level, error correction coding, and spectrum spreading. In addition, a path for the data is preferably selected according to an Open-Shortest-Path-First algorithm, though one or more alternate paths can be selected for transmitting at least a portion of the data.