Other Research Activities
Network Synchronization
The telecommunications infrastructure currently installed consists basically of digital switches and transmission links of Plesiochronous Digital Hierarchy (PDH), Synchronous Optical Networks (SONET), or Synchronous Digital Hierarchy (SDH). The efficient implementation of a switching fabric requires a synchronous multiplexed frame format. Before the signal is fed into the multiplexer, the signal frames are phase aligned in an elastic store of the synchronizer, in order to implement the synchronous multiplexing. The frequency (or bit rate) offset due to synchronization failure is accommodated in the elastic store and results in slips. In order to control the slip rate performance, ITU-T Recommendation G.822 and G823 give the basis for jitter and wander specifications.
The network synchronization quality has an impact on the jitter and wander performance, which may increase the bit error rate or frame slips. Thus, we have made efforts on the study of jitter and wander. The jitter and wander reduction mechanisms are under studied. The development of frequency synchronization technology in the telecommunication networks is also in progress