Novel Receiver Architecture for LTE-A Downlink Physical Control Format Indicator Channel with Diversity

Physical control format indicator channel (PCFICH) carries the control information about the number of orthogonal frequency division multiplexing (OFDM) symbols used for transmission of control information in long term evolution-advanced (LTE-A) downlink system. In this paper, two novel low complexity receiver architectures are proposed to implement the maximum likelihood- (ML-) based algorithm which decodes the CFI value in field programmable gate array (FPGA) at user equipment (UE). The performance of the proposed architectures is analyzed in terms of the timing cycles, operational resource requirement, and resource complexity. In LTE-A, base station and UE have multiple antenna ports to provide transmit and receive diversities. The proposed architectures are implemented in Virtex-6 xc6vlx240tff1156-1 FPGA device for various antenna configurations at base station and UE. When multiple antenna ports are used at base station, transmit diversity is obtained by applying the concept of space frequency block code (SFBC). It is shown that the proposed architectures use minimum number of operational units in FPGA compared to the traditional direct method of implementation. 1. Introduction The goal of third generation partnership project (3GPP) long term evolution-advanced (LTE-A) wireless standard is to increase the capacity and speed of wireless data communication. The LTE-A physical layer is a highly efficient means of conveying both data and control information between an enhanced base station, popularly known as eNodeB, and mobile user equipment (UE). It supports both frequency division duplex (FDD) and time division duplex (TDD) configurations in uplink and downlink operations. Further, it provides a wide range of system bandwidths in order to operate in a large number of different spectrum allocations [1]. LTE-A standard has six physical channels for downlink. They are physical broadcast channel (PBCH), physical downlink shared channel (PDSCH), physical multicast channel (PMCH), physical downlink control channel (PDCCH), physical hybrid automatic repeat request (ARQ) indicator channel (PHICH), and physical control format indicator channel (PCFICH). PBCH carries the basic system information for the other channels to be configured and operated in the LTE-A grid. The PDSCH is the main data-bearing channel. PMCH is defined for future use. In LTE-A, the control signals are transmitted at the start of each subframe in the LTE-A grid. PDCCH is used to carry the scheduling information of different types such as downlink resource scheduling and uplink power