Research On Mechanism Of Reducing Papr In60Ghz Millimeter-Wave Communication Systems

With the demand for high-speed high-quality wireless communications services as well as the rapid development of wireless communication technology, ultra-wideband (UWB) wireless technology and the IEEE802.11n standard can only be provided at a rate of hundreds of Mbps, has been unable to meet the demand for the development of wireless technology. Moreover, low-frequency wireless communication band (2.4GHz ISM band) has been particularly crowded, and this greatly limiting the development of new technologies.60GHz millimeter wave band on its huge license-free bandwidth resources to support up to Gbps data rate.Two modulation schemes, namely Single-Carrier (SC) and Orthogonal Frequency Division Multiplexing (OFDM), are adopted in the draft of60GHz millimeter waves IEEE802.11ad. Low Density Parity Check (LDPC) codes is adopted in the draft in terms of its much better performance in correcting errors comparing other FEC codes. However, OFDM system is vulnerable to be influenced by60GHz power amplifier (PA) nonlinear distortion for its high peak to average power ratio (PAPR).In this paper, we first utilize the selected mapping principle (SLM) combined with the fact of the high density of LDPC generator matrix. When the bit rate is relatively large, we further propose a novel non-system code to build a way to maximize system performance. For multi-ary modulation, we utilize a non-binary LDPC codes, compared to the binary LDPC codes, this can further improve system performance. Experimental results confirm LDPC has much better performance in reducing PAPR and resisting PA nonlinear distortion comparing other FEC codes. We also we utilize a promising companding transform (CT) algorithm which is also combined with predistortion scheme. Not only can well reduce nonlinear distortion, can it also solve the issue of PA power efficiency. This can effectively alleviate the PA nonlinear distortion, improving system performance.The proposed algorithm that combined SLM and LDPC to reduce the PAPR, and exploratory proposed combination based the companding transform and predistortion algorithm. The algorithm not only suitable for the60GHz millimeter wave communication system, and for other OFDM systems with universality; and the non-systematic code, we can still obtain performance when the code rate is larger, moreover the algorithm is relatively simple, and can be parallel computing, and thus has great practical value in the actual high-speed60GHz millimeter-wave system.