Doppler-Free Digital Communications

| The existence of doppler has always been an inconvenience for digital communications. Several schemes have been proposed to deal with the problem, often involving some kind of doppler tracking and/or compensation algorithm. All these schemes do, however, increase the complexity of the receiver. Furthermore, the need for exactness in the doppler tracking scheme adds an extra dimension to the space of potential failures. In this article, we will follow a di erent approach. By using time-frequency methods in the detection/decoding stage, we will be able to design receivers which are, in fact, doppler insensitive. The existence or non-existence of doppler e ect becomes irrelevant as far as the receiver performance