Digital Compensation for Analog Front-Ends: A New Approach to Wireless Transceiver Design

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Introduction

1.1 Wireless transceiver functional description

Emerging wireless communication systems are carefully designed to optimize at the same time the offered user capacity, the average spectral efficiency and the cell coverage. A set of complementary functions are successively implemented at the transmitter and at the receiver to support the communication while still respecting the power consumption and spectral occupancy constraints. Figure 1.1 gives a functional description of a typical wireless transceiver. Part of the functions are implemented on a digital processor (block (A) at the transmitter and block (D) at the receiver). The other part of the functions are implemented in the analog front-end (block (B) at the transmitter and block (C) at the receiver). In the following paragraphs, we give a synthetic description of the main transceiver functional blocks.

The channel coder adds structured redundancy to the bit stream at the transmitter that can be used at the receiver by the channel decoder to detect and ultimately correct the bit detection errors generated by various sources of signal distortion in the system. The interleaver/deinterleaver pair makes sure that the errors happen at random locations in the bit stream (bursts of errors are avoided).

At the transmitter, the constellation mapper converts the stream of coded bits into a stream of complex symbols. The necessary physical bandwidth is directly proportional to the symbol rate, so that high constellation ...