Orthogonal frequency domain multiplexing (OFDM) communication system

摘要

An OFDM communication system employs a cell time division time frame for a plurality of overlapping cells wherein the time frame comprises time slots with each time slot allocated to one of the overlapping cells and each time slot being either an information exchange time slot or a data time slot. Remote nodes (101-105) transmit resource requests for at least one subcarrier in a data time slot to one or more of the central nodes (107, 109) in the information exchange time slots of those nodes (107, 109). The central nodes (107, 109) broadcast information of uplink channel characteristics received in the request messages and the remote nodes (101-105) use this to determine whether to abandon or continue the resource request. Eventually, the remote node may decide to use the resource and thus to transmit in the associated data time slot. A distributed multi-cell resource allocation can be achieved based on distributed decisions in the remote stations.

主权项

1. An Orthogonal Frequency Domain Multiplexing (OFDM) communication system employing a cell time division time frame for a plurality of cells, the time frame comprising time slots with each time slot allocated to one of the plurality of cells and each time slot being either an information exchange time slot or a data time slot, the communication system comprising:
a plurality of remote nodes each comprising a computing device and non-transitory memory in communication with the computing device, the non-transitory memory storing instructions that, when executed by the computing device, cause each of the remote nodes to implement:
a resource processor for determining a requirement for uplink resource;a node selection processor for determining a first central node from which to request uplink resource, wherein the node selection processor can select the first central node as any central node of a plurality of central nodes each of which supports a cell of the plurality of cells;a channel characteristic processor for determining a channel characteristic for the uplink communication channel between the remote node and the first central node;a time slot controller for determining a first information exchange time slot of the time frame allocated to the first central node;a request message controller for transmitting a resource request for at least one subcarrier of a data time slot to the first central node in the first information exchange time slot, the resource request comprising an indication of the channel characteristic;an indication message controller for receiving an indication message from the first central node in the first information exchange time slot, the indication message comprising a combined channel indication of the received channel conditions for all received resource requests for the at least one subcarrier in the first information exchange time slot;a resource controller for performing a sequence comprising:
when the resource controller determines the channel quality for an uplink communication from the remote node is below a threshold, abandoning the request; andwhen the resource controller determines the channel quality for the uplink communication from the remote node is above the threshold, repeating the transmission of the resource request and continuing to contend for the requested resource:wherein the resource controller performs one or more additional iterations of the sequence using a successively higher threshold for each iteration until either the resource controller decides to abandon the request or the resource controller decides to use the at least one subcarrier in the data time slot; anda data communication controller for transmitting uplink data to the first central node on the at least one subcarrier in the data time slot when the resource controller decides to use the at least one subcarrier in the time slot;wherein at least one of the plurality of remote nodes is arranged to transmit resource requests to a plurality of central nodes in a single time frame.