Research On RNS/RRNS-based Parallel Transmission Methods

With the rapid development of the communication, the communication transmission faces bigger challenge of spectrum resources scarcity, extremely high data rate and high power-efficiency. It needs some technologies which can use spectrum efficiently and make a breakthrough in capacity improvement. The parallel transmission technologies, such as orthogonal frequency division multiplexing(OFDM), multiple-input multiple-output(MIMO) and MIMO-OFDM, have become the key technologies for the future communication transmission. These technologies make ultimate use of spectrum resources to improve the spectrum efficiency and guarantee to fight against a variety of unfavorable factors for realizing the high-bit-rate low-error-rate communication. However, some intrinsic drawbacks of such technologies are still problems to be solved. Among the drawbacks, the high peak to average power ratio(PAPR), one of the representative problems, will bring a contradiction between performance and cost. Meanwhile, MIMO will bring a contradiction between parallelism and complexity. When the antenna’s number of MIMO increases, the PAPR problem would become worse, and would even degrade the system’s performance. Therefore, the PAPR problem has become one of the bottlenecks for the future communication technologies. These years, great interest has been focus on PAPR reduction.Residue number system(RNS), which utilizes the parallel property to convert input signals into the parallel smaller residue signals, can realize the system’s parallel directly. Unlike traditional methods, RNS can improve the parallelism with efficiently control of the system scale. Due to the signal-processing properties of parallel, carry-free, and fault-tolerant, RNS can be adapted to fulfill the high-speed, reliable, low-power transmission requirements. Recently, more attention has been paid to applying RNS in communication systems, particularly, using RNS for encoding or resource allocation for reliability improvement of the system.Based on the problems mentioned above, we will further explore the properties of RNS and focus but not limited on the description, some basics and system performance the RNS-based parallel transmission method. The dissertation intends to provide an alternative to reduce the scale of parallel system and complexity, meanwhile to provide an efficient solution to alleviate the common problems of parallel system. The main research work is as follows:1. An RNS based parallel transmission method is proposed. The proposed method utilizes the parallelism of RNS to realize the parallel transmission, which can limit the general system’s complexity and reduce the complexity of each residue sub-channel.2. The construction of RNS based parallel transmission method is demonstrated using the representative OFDM as an example. The transmission bandwidth and spectrum efficiency of the proposed method are analyzed. It implies that the proposed method doesn’t increase the cost of spectrum resources and possibly would seek a tradeoff between power and bandwidth by adjusting the dynamic range.3. An RNS based PAPR reduction method is proposed without the need of reducing the power of output or using the high linear amplifier. The proposed PAPR reduction method reduce the PAPR without distortion with full use of the existing linear region of amplifier.With the proposed method, the PAPR of original OFDM is improved above 5dB and outperforms the popular lossless PAPR reduction methods(SLM, PTS) without sideband information.4. Compared with the traditional methods which trade the scale for the performance in multi-antenna scenario of MIMO-OFDM, we explore the parallelism characteristics of RNS, which realize the parallel transmission from the front-end modules. It has shown the proposed RNS is capable of limiting the scale and complexity of multi-antenna systems efficiently. When the number of antennas increases, the PAPR performance of MIMO-OFDM gets worse than that of the single antenna OFDM. When the traditional lossless PAPR reduction schemes are applied in MIMO scenarios, the scale and complexity of systems doubles, when the number of antennas increases. However, the flexible RNS-PAPR method improves the PAPR reduction performance in MIMO-OFDM significantly and maintains the advantage of the low complexity.