Interference Cancellation for Evolved EDGE on the RazorEDGE baseband ASIC
With the latest standard extension EGPRS2, GSM can provide downlink data rates up to 1.2 Mb/s. Such performance improvements demand tight constraints regarding transmit power and signal to interference ratio compared to legacy GPRS receivers. Especially in urban areas todays cellular networks are interference limited rather than noise limited. Interference in cellular radio systems can be divided into co-channel interference and adjacent channel interference. The latter is mainly arising from users being served by the same base station, while the former arises from users of neighboring cells.
The introduction of mobile station receive diversity in the latest GSM specifications (DARP phase 2), is helpful in order to achieve the high performance requirements. Receive diversity enables sophisticated interference cancellation concepts to be applied, which are computationally more demanding than single antenna interference cancellation approaches. Dedicated hardware implementations are suited for such computationally intense algorithms and might prove more efficient in terms of power than DSP based implementations.
In this project a two-stream interference canceller was implemented as part of the RazorEDGE baseband ASIC. RazorEDGE is a PHY modem for EGPRS2 Level A employing advanced baseband signal processing algorithms including interference cancellation, channel equalization and decoding.