Abstract: A method and apparatus for a self-correcting bandwidth request/grant protocol in a broadband wireless communication system is disclosed. The self-correcting bandwidth request/grant protocol utilizes a combination of incremental and aggregate bandwidth requests. In accordance with the present inventive protocol, CPEs primarily transmit incremental bandwidth requests to their associated base stations, followed by periodic transmissions of aggregate bandwidth requests. The use of incremental bandwidth requests reduces risks that a base station erroneously issues duplicate bandwidth allocations to the same CPE for the same connection. Race conditions that may have occurred using only aggregate bandwidth requests are eliminated by requiring the CPEs to request bandwidth in an incremental manner. However, use of periodic aggregate bandwidth requests (that express the current state of their respective connection queues) allows the present bandwidth allocation method and apparatus to be “self-correcting”.

Abstract: A method for allocating fractional bandwidth in a fixed-frame communication system is described. The method includes calculating the integral cells per frame required at a connection, calculating the fractional cells per second required at the connection, setting a counter, adding the fractional cells per second to the counter, determining if the counter is above a preset limit, allocating an additional cell when the counter exceeds the preset limit, and reducing the counter a predetermined amount to reflect allocating the cell.

Abstract: A system and method for enhancing the performance of an equalizer in a modem. Multiple techniques are disclosed which improve the modem performance. A first technique uses stored parameters for each burst from each remote site to demodulate a received data stream. A second technique compensates for the gain droop caused by storing parameters across each burst. A third technique minimizes errors caused by adapting the equalizer coefficients for each data burst by analyzing the SN ratio and error rate of the received burst. A fourth technique improves the convergence of the equalizer by using a two-part preamble, whereby both parts are transmitted using different modulation techniques. A fifth technique is provided which performs a soft reset of the modem without performing a complete reset of the modem. A sixth technique determines a modem adaptation factor based on the expected modulation type of an incoming burst transmission.

Abstract: A system that provides a redundant wireless broadband connection between a base station and customer sites is described. The system includes a redundancy system, for example, a standby modem interface card and a plurality of standby outdoor units that are incorporated into the base station. Upon receiving a fault message from a base station component, the redundancy system performs fault correlation to determine whether the fault is indicative of a system level fault. The system also determines whether the fault message affects system operation and performs a switch over based on the determination.

Abstract: On embodiment of the system and method provides asymmetric adaptive modulation which allows uplink and downlink subframes of data to be transmitted between a base station and a CPE with different modulation schemes, thus increasing the efficiency of downlink transmissions while maintaining the stability of uplink transmissions. In systems with multiple CPEs, each CPE and base station pair can independently select their uplink and downlink modulation techniques. The system and method are also adaptive in that they adjust the modulation schemes based on, for example, signal to noise ratio measurements or bit error rate measurements.

Abstract: Disclosed is a novel method and system for efficiently synchronizing, transmitting, and receiving data between a base station and a plurality of customer premises. A MAC coprocessor (MCP) is implemented, which works in conjunction with the MAC in order to produce a robust, high throughput communication system. The MAC coprocessor performs many of the tasks typically performed by prior art MAC's, including: during a downlink, storing a data frame, sorting the data frame according to modulation type or other criteria, determining when the data frame is full, and appending a set of CPE settings to the data frame. During an uplink, the MAC coprocessor receives all data and routes the data either to the MAC or a network backhaul. A MAC coprocessor may be used in both the base station and Customer Premises. In both the downlink and uplink processes, having a MAC coprocessor working in conjunction with the MAC may significantly increase the communication system's throughput.

Abstract: An adaptive time division duplexing (ATDD) method and apparatus for duplexing transmissions on a communication link in wireless communication systems. Communication link efficiency is enhanced by dynamically adapting to the uplink and downlink bandwidth requirements of the communication channels. Time slots are flexibly and dynamically allocated for uplink or downlink transmissions depending upon the bandwidth needs of a channel. Communication link bandwidth requirements are continuously monitored using sets of pre-determined bandwidth requirement parameters. Communication channels are configured to have either symmetric or asymmetric uplink/downlink bandwidths depending upon the needs of the channel. Channel bandwidth asymmetry can be configured alternatively in favor of the uplink transmissions (i.e., more time slots are allocated for uplink transmissions than for downlink transmissions) or in favor of the downlink transmissions (i.e.