Design and real-time measurement of HSDPA equalizers

The high speed downlink packet access (HSDPA) is an extension to UMTS that is tailored to high packet data throughput up to 14.4 Mbps. In order to reach these high data rates, it is indispensable for the receiver to cancel multiple access interference (MAI) as to obtain a sufficiently high channel quality. In practice this renders the usage of conventional RAKE receivers impossible and makes equalization attractive to circumvent these problems. This paper describes and compares known equalization schemes (MMSE, selected adaptive techniques) as well as new proposals (MMSE-RAKE). Other than related publications, the performance evaluation is based on measurements over a physical channel at 2.45 GHz and is hence truly representative for a real HSDPA system. Further, the comparison is drawn both on performance and complexity, keeping a real-time implementation in focus.