On 3G LTE Terminal Implementation - Standard, Algorithms, Complexities and Challenges

Currently, 3GPP standardizes an evolved UTRAN (E-UTRAN) within the Release 8 Long Term Evolution (LTE) project. Targets include higher spectral efficiency, lower latency, higher peak data rate when compared to previous 3GPP air interfaces. The air interface of E-UTRAN is based on OFDMA and MIMO in downlink and on SCFDMA in uplink Main challenges for a terminal implementation include efficient realization of the inner receiver, especially for channel estimation and equalisation, and the outer receiver including a turbo decoder which needs to handle data rates of up to 75 Mbps per spatial MIMO stream. We show that the inner receiver can nicely and straightforwardly be parallelized due to frequency domain processing. In addition to the computational complexity of even a simple linear equaliser, one of the challenges is an efficient implementation considering necessary flexibility for different MIMO modes, power consumption and silicon area. This paper will briefly overview the current LTE standard, highlight a functional data flow through the single entities of an LTE terminal and elaborate more on possible first implementation details, including sample algorithms and first complexity estimates.