Authors: Tuomo Hänninen Janne Janhunen Markku Juntti
Publish Date: 2013/09/13
Volume: 78, Issue: 3, Pages: 645-655
Abstract
We summarize our recent stateoftheart programmable and reconfigurable detector and QR decomposition QRD implementations targeting 3G long term evolution LTE downlink and uplink requirements The downlink transmission is based on the orthogonal frequency division multiplexing whereas the uplink transmission uses a singlecarrier frequencydivision multiple access The downlink implementations are based on the programmable transport triggered architecture TTA which provides a flexible and energy efficient architecture template In TTA detector implementation the LTE detection rate requirements up to 20 MHz bandwidth and 4 × 4 antenna system with 64QAM are achieved by using 1–6 programmable cores in parallel Each core runs at 277 MHz clock frequency and consumes 555–640 mW depending on the detector configuration The downlink detector is based on the selective spanning with fast enumeration algorithm The uplink fieldprogrammable gate array FPGA detector implementation is targeted for 4 × 4 antenna system and 64QAM achieving a detection rate requirement for 20 MHz bandwidth The used FPGA board for uplink implementation is Xilinx Virtex6 and the implementation has been carried out using Xilinx Vivado high level synthesis tool Two different detector architectures are implemented The first one achieves the detection rate requirement with a single processing block running at 231 MHz and the latter one with four blocks in parallel each running at 247 MHz The implemented detector is based on the Kbest algorithm A multipleinput multipleoutput receiver requires QRD to produce valid inputs for the detector In addition to detector implementations QRD is also implemented on both TTA and FPGA Modified Gram–Schmidt algorithm is used in both QRD implementationsThe authors would like to thank Xilinx Inc especially J Noguera B Ozgul and J Keskinen for the possibility to evaluate Xilinx Vivado High Level Synthesis tool and for their cooperation The authors would also like to thank J Ketonen for her efforts related to this paper
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