Controlling communications

摘要

Devices communicating on a shared communication channel using a frame structure are allocated a certain number of time slots at the start of each frame to listen for interference from other devices using the channel. Each device then makes a decision on whether to transmit using the remaining frame symbols based on any detected interference. The allocation may be made by a NodeB or other control device depending on the network used. The number of time slots is preferably different for each device or cell, so that devices spend different amounts of time listening for interference and the chance of collisions is therefore reduced. The number of time slots may change for successive sub-frames of a frame, or for transmission in the uplink and downlink directions.