Receiver synchronization and Radio Link Monitoring (RLM) support important functions in the typical wireless communication network. For example, in wireless communication networks operating according to Long Term Evolution (LTE) standards, (primary and secondary) synchronization signals transmitted from eNBs allow mobile terminals or other items of User Equipment (UE) to detect and synchronize with new cells, for signal quality/strength measurements that enable good handover (HO) decisions. Similarly, RLM allows individual terminals to detect radio link failure and other communications problems, and take or otherwise trigger appropriate actions, such as reconnection or link recovery processing.
However, for a number of reasons including energy efficiency on the network side and battery life improvements on the terminal side, the developing wireless communication standards make increasing use of DTX (discontinuous transmission) and/or DRX (discontinuous reception). For example, in LTE the eNBs may DTX to save power, or for other reasons, and, likewise, the UEs may use DRX, both of which complicate channel quality estimations due to limited measurement opportunity. In the LTE standard, the RLM function requires UE to regularly monitor the serving cell quality and based on the estimated quality detect “in sync” and “out of sync” status of the radio link of the serving cell. The reference signals are used to derive the serving cell quality for the purpose of the RLM. The power saving in LTE eNB may lead to reduction in reference signal transmission and would therefore negatively impact the RLM performance.