60 Ghz In Uwb System Research Of Beam Forming Algorithm

With the development of multimedia applications, wireless communicationincreases requirements of the transmission rate and signal bandwidth, which providemarket for60GHz wireless communications. However, because of its link budgetconstraints, the design of millimeter-wave band radio is facing some challenges. For60GHz systems, in order to overcome the enormous path loss, the use of beamformingwhile taking advantage of the antenna array in the transmitter and receiver is a veryimportant technology.This paper focuses on60GHz communication systems, in which the channelreciprocity based beamforming is used as a key technology. We briefly discuss severaltypical beamforming algorithms, and research on the most representative Eigen BasedBeamforming (EBB) algorithm. Considering the correlation between each subcarrier inthe frequency domain of MIMO-OFDM (Multi-Input Multi-Output—OrthogonalFrequency Division Multiplex) system, we propose a new First Order PerturbationCompensation based EBB (FOPC-EBB) algorithm and introduce the idea of blocking,just for the purpose of reducing the complexity of the system. Then, through studyingthe power iteration beamforming algorithm, we obtain the basic understanding ofiteration beamforming without channel estimation, and then propose the orthogonaliteration beamforming. Also, we validate and analyze the above algorithms throughcomputer simulation.In chapter one, we briefly discuss60GHz communication system, the researchbackground and current situation of beamforming technology and then introduce theidea of this study, the basic architecture and the author’s main work.In chapter two, for the need of the following algorithms design and simulation,firstly we discuss the signal model of single-user beamforming in MIMO-OFDMsystem, and then discuss the channel transmission characteristics, channel impulseresponse and power delay profile of one kind of60GHz systems-IEEE802.15.3cstandard, and so on. And also we research on several current typical beamformingtechnologies, in which we focus on the EBB algorithm. In chapter three, we mainly research on channel reciprocity based beamformingtechnology-EBB algorithm, FOPC (First Order Perturbation Compensation) and theidea of subcarrier blocking in TDD (Time Division Duplex) system. After synthesizingthem, we propose a FOPC-EBB-BLOCK beamforming algorithm, utilizing thecorrelation between the channel matrixes in the frequency domain to lower thecomplexity. Through blocking all the subcarriers and setting a corresponding threshold,the algorithm reduces the number of decomposition of the system matrices, therebyreducing the complexity of the system. Then, for60GHz indoor transmission system inboth LOS and NLOS scenes, we simulate the algorithm and analyze the performance.In chapter four, considering that the current beamforming technologies have to dochannel estimation and feedback the beamforming vectors, we study and analyze thepower iteration beamforming algorithm, discovering that it is of relatively highcomplexity to transmit multiple data streams, so we propose an orthogonal iterationbeamforming algorithm based on QR decomposition. The algorithm can calculatebeamforming vectors for multiple data streams, and is more suitable for the60GHzsystem, which has more transmit and receive antennas.Finally we summarize the work of this article, and point out possible researchdirections in the future.