标题: 好书！Signal Processing Requirements for WiMax 802.16e Base Station [打印本页] 作者: szdhl 时间: 2008-6-1 11:34 标题: 好书！Signal Processing Requirements for WiMax 802.16e Base Station Abstract
802.16e provides specifications for non line of sight, mobile wireless communications in the frequency range of 2-6 GHz. It is well implemented by using OFDMA as its physical layer scheme. The OFDM symbol time (sT) is to be selected depending on the channel conditions, available bandwidth and, simulations provide a means of selecting right values of sTin different channel conditions. Additionally it has been shown that certain values of sT outperform others in all conditions, thus invalidating their use. Moreover, a solution proposed by INTEL is also analyzed.
One of the major requirements of OFDM is high synchronization. Detecting the timing offset of a new mobile user, entering the network, which is not time aligned using cross-correlation and ‘auto-correlation’ in time domain and cross-correlation in frequency domain at the base station has been simulated. Results point that the processing load can be significantly reduced by using frequency domain correlation of the received data or by using ‘auto-correlation’ followed by cross-correlation on localized data.
The use of adaptive antenna system in 802.16e improves the system performance, where beamforming is implemented in the direction of desired user. Capon’s method and MUSIC method have been simulated to compute the direction of arrival for OFDMA uplink. A new user, while in the ranging process, transmits data with unknown time offset and unknown direction. The thesis describes the procedure to find the two unknown one after another.
PART 0: INTRODUCTION....................................................................................................1
0.1 GOAL OF THE THESIS.........................................................................................................3
0.2 REPORT OUTLINE...............................................................................................................3
0.3 INTRODUCTION TO WIMAX..............................................................................................3
0.3.1 802.16c.................................................................................................................................3
0.3.2 802.16a.................................................................................................................................4
0.3.3 802.16d.................................................................................................................................4
0.3.4 802.16e.................................................................................................................................4
0.4 OFDM SYSTEM DESCRIPTION............................................................................................5
0.4.1 Effects of Receiver performance............................................................................................7
PART 1: CHANNEL ESTIMATION.....................................................................................9
1.1 INTRODUCTION..................................................................................................................9
1.2 UP LINK TRANSMISSION....................................................................................................9
1.3 THE BLOCK DIAGRAM.....................................................................................................10
1.3.1 Transmitter.........................................................................................................................11
1.3.2 Channel...............................................................................................................................12
1.3.3 Receiver..............................................................................................................................15
1.4 PROBLEM DESCRIPTION...................................................................................................17
1.5 SIMULATION RESULTS.....................................................................................................18
1.5.1 Performance in AWGN channel..........................................................................................18
1.5.2 Performance in a Rayleigh Fading Channel.......................................................................20
1.5.3 Effect of mobile speed..........................................................................................................23
1.5.4 Performance in presence of Multipath................................................................................24
1.5.5 Effect of multipath delay spread..........................................................................................28
1.5.6 Effect of Channel coding.....................................................................................................30
1.6 DISCUSSION.....................................................................................................................32
PART 2: RANGING..............................................................................................................34
2.1 INTRODUCTION................................................................................................................34
2.2 PROBLEM DESCRIPTION...................................................................................................35
2.3 TIMING OFFSET CALCULATION.........................................................................................35
2.3.1: Cross-correlation in time domain......................................................................................35
2.3.2: Auto-correlation in time domain........................................................................................36
2.3.3: Correlation in frequency domain.......................................................................................37
2.4 FREQUENCY AND POWER OFFSET CALCULATION.............................................................39
2.5 SIMULATION RESULTS.....................................................................................................39
2.6 PROCESSING LOAD CALCULATION...................................................................................42
PART 3: ANTENNA BEAMFORMING.............................................................................46
3.1 INTRODUCTION................................................................................................................46
3.2 BEAMFORMING BASICS....................................................................................................47
3.3 TYPES OF BEAMFORMING.................................................................................................48
3.4 PARAMETERS EFFECTING BEAMFORMING........................................................................50
3.5 ADAPTIVE ANTENNA SYSTEM FOR OFDMA IN 802.16E..................................................50
3.6 DIRECTION OF ARRIVAL COMPUTATION (DOA)...............................................................53
3.6.1 Capon’s method...................................................................................................................53
3.6.2 MUSIC algorithm................................................................................................................54
3.7 SIMULATION RESULTS.....................................................................................................54
3.8 CONCLUSION...................................................................................................................57
A. REFERENCES..................................................................................................................60
B. ACRONYMS......................................................................................................................62 ix作者: unclebearbear 时间: 2008-6-1 13:54
谢谢 ，很好作者: unclebearbear 时间: 2008-6-1 13:56
谢谢 ，很好作者: 注册公司6 时间: 2008-6-1 22:40 标题: 拳王
