Transmission medium, or channel, is one of the major components in a digital communications system. The transmitted signal must pass through channel reach the receiver. Channel is also where where the impairments to signal including, distortions and Additive noise and interference. To achieve best possible performance, it is necessary for a communications to have the knowledge of the channel characteristics as precise as possible. Thus, one important task of receiver design and implementation is to accurately estimate various parameters of the communication channel. It is not exaggerating to say that accurate estimation of channel characteristics is the key to combat the introduced impairments in order to achieve best possible system performance.
In a wireless communication system, channel estimation is even more important. It is because due to the nature of the wireless communication channel, it is always time varying. It’s characteristics can change rapidly. Thus, it is impossible to track the magnitude and phase of the channel by using classical means used in wireline communication systems, e.g., phase locked loop. In that sense, channel estimation is also an integrated part of synchronization.
Recently, using self-interference cancellation to achieve full-duplex communication in wireless systems has attracted attention in the wireless research community and industry. The level of achievable cancellation of the linear component of the interference is totally determined by the accuracy of the interference channel estimation. Thus, it is essential to understand the limit of the channel estimation in the design and implementation of this technology.
In this presentation, these aspects of channel estimation and their theoretical foundations are discussed.
The presentation can be viewed or downloaded from here.