在無線通訊中，為了提升頻譜使用效率，雙向中繼傳輸是一個有效的傳輸方式，而雙向中繼傳輸是利用兩個使用者中間的中繼點，在同一時間以及同一頻帶來幫忙傳輸；不管是傳統的傳輸方式或者是近幾年來備受關注的合作式通訊，在某個使用者傳送訊息給另外一個使用者時，如果兩個使用者彼此的距離太遠，我們就必須考慮利用多重跳躍機制來傳輸，才不會使系統傳輸的錯誤率太低。
　　在此篇論文中，我們提出了一個新的雙向解碼轉送中繼網路之合作式多重跳躍傳輸機制，此機制分成了兩個部分，第一個部分為轉送點選擇，第二部分為中繼點選擇，轉送點選擇是為了減少系統傳輸跳躍的次數，中繼點選擇則是為了提升傳輸通道的品質來降低系統傳輸錯誤率；在這兩種選擇中，為了提升我們選擇的效率，我們將基於漸近的符元錯誤機率條件去找出一個可選擇的集合或是範圍，我們從每次找出的集合中來選出轉送點或是中繼點，並且建構出系統的傳輸路徑；最後我們也推導出整體系統漸近的符元錯誤機率。

Two-way relaying is a promising technique to improve the spectral efficiency of wireless communications, where a relay or a set of relays are used to realize information exchange between two sources at the same time and frequency. For long distance transmission, two-way relaying needs to be further combined with a multihop routing mechanism for efficient information exchange. In this thesis, we propose a new cooperative multihop transmission scheme for two-way decode-and-forward relay networks, in which multiple single-antenna relays are considered and distributed between two sources. The proposed scheme mainly consists of a forwarder selection part and a relay selection part; the former aims to minimize the number of transmission hops, and the latter is used to improve the reliability of communication links. We obtain the coverage regions of available relays and forwarders based on an asymptotic symbol error probability (SEP) analysis, and then combine the results with geographic information for minimum-SEP relay selection and maximum-coverage forwarder selection. It is shown that the proposed approach provides better effective throughput performance than a related method. In addition, an asymptotic overall end-to-end SEP for the proposed scheme is derived with a closed-form expression. Simulation results are given to validate the analyses as well as to demonstrate the effectiveness of the proposed approach.

Abstract i
Contents iii
List of Figures v
List of Tables vii
Chapter 1 Introduction 1
Chapter 2 A Symbol Error Probability for Two-Way Decode-and-Forward Relaying Systems [20] 6
2.1 System Description 6
2.2 Symbol Error Probability Analysis 7
2.3 Discussions 12
Chapter 3 A Multihop Transmission Scheme with Detect-and-Forward Protocol and Network Coding in Two-Way Relay Fading Channels [19] 13
3.1 Network Description 13
3.2 Bit Error Rate Analysis 16
3.3 Discussions 20
Chapter 4 A Cooperative Multihop Transmission Scheme for Two-Way Decode-and-Forward Relaying Networks 21
4.1 Motivation 21
4.2 Network Description 22
4.3 SEP-Based Radio Coverage 26
4.3.1 A Set of Available Forwarders 26
4.3.2 A Set of Available Relays 29
4.4 Cooperative Two-Way Routing 30
4.4.1 A Routing Protocol 30
4.4.2 Contention Timer Setting for Forwarder Selection 32
4.4.3 Contention Timer Setting for Relay Selection 34
4.5 An Asymptotic Overall End-to-End SEP Analysis 36
Chapter 5 Simulation Results 39
Chapter 6 Conclusions 48
References 50

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