Increasing HSDPA throughput by employing space-time equalization

In the downlink of wideband code division multiple-access (WCDMA) systems, users are assigned orthogonal spreading codes. A multipath radio channel distorts the spreading waveforms causing interference between users. This so-called multiple-access interference is especially harmful in case of data transmission which may require both high quality and high transfer speed. Since the interference is caused by the channel, the most straightforward way of suppressing the interference is to apply linear channel equalization. We apply linear chip-level equalization to high-speed downlink packet access (HSDPA) signal. Moreover, we study the performance improvement when dual-antenna receivers are used in the mobile terminal. Data throughput gains are evaluated in a multipath environment both at link level and at system level for which we present a simple simulation technique.