Link adaptation with load-dependent BLER target value

摘要

The prior art link adaptation has been designed to adapt the modulation scheme according to the SINR, in order to achieve a stable transmission error rate, e.g. 10% retransmission. However this strict algorithm used to be too robust and could not work well in case of congestion, which results into huge buffer queuing and also starvation to each other. Thus a problem is that when the user equipment in congestion e.g. a bad channel condition, the base station cannot provide a certain VolP user equipment with the required bit rate. The consequence is that the QoS requirement of such a VolP user equipment will not be met regardless of which scheduling algorithm has been used, and all the scheduled resources allocated to this user equipment are useless and wasted. This problem is solved by increasing the value of the BLER of the link adaptation in relation to the initial value to be more aggressive (304). Then the buffer in the user equipment is cleared to free resources which may be used by other user equipments, which in turn enhances the performance in the wireless communications network.