在無線隨意區域網路(wireless ad hoc network)系統裏，媒體存取層的設計與實體層的能力充分影響著系統的效能與容量。本論文將提供一全新以CDMA為基礎的無線隨意區域網路系統，並且設計一媒體存取協定來配置各通信節點(node)在資料通道(data channel)上分割的時槽(time slot)之演算法以及在控制通道(control channel)上競爭存取的方式來加強系統的效能與容量。在資料通道裏，我們將一個時框(frame)分為164個時槽，每個時槽可以依照固定式時槽配置演算法(fixed time slot allocation; FTSA)和混合式時槽配置演算法(mixed time slot allocation; MTSA)分配的結果傳送固定位元速率(constant bit rate; CBR)，變動位元速率(variable bit rate; VBR)或是可用位元速率(available bit rate; ABR)的流量類別。當節點在競爭通道上取得虛擬雜訊碼(pseudo noise code; PN code)與傳送的時槽後，將同時保證傳送的頻寬。通常在同一時槽裡，CBR最多可以有41組節點同時傳送資料，而VBR最多可以有17組節點同時傳送資料，ABR則最多可以有11組節點同時傳送資料。在控制通道裏，我們使用碰撞避免式載波偵測多重存取(carrier sense multiple access with collision avoidance; CSMA/CA)的競爭方式讓各節點取得傳送的PN Code以及配置的時槽，然後在資料通道使用。經過模擬程式的結果，證明系統的效能與容量提升了數倍。

In wireless ad hoc network system, the design of medium access control (MAC) layer and the ability of the physical layer sufficiently affects the performance and capacity of the system. In this paper, we propose a new MAC layer protocol in the wireless ad hoc network system based on code division multiple access (CDMA). The channel has been divided into control channel and data channel, in which a data channel is divided into 164 slots. The proposed MAC layer protocol may allocate the slots in each frame for every node by two different slot allocation algorithms: fixed time slot allocation (FTSA) and mixed time slot allocation (MTSA). Each slot can be used to transmit different traffic types such as constant bit rate (CBR), variable bit rate (VBR), and available bit rate (ABR). A node obtains a guaranteed bandwidth to transmit its packets after obtaining a set of pseudo noise code (PN code). Generally 41 sets of PN codes can be used to transmit CBR traffic in the same slot, while 17 and 11 sets of PN codes are used to transmit VBR and ABR traffics, respectively. In the control channel, we use carrier sense multiple access with collision avoidance (CSMA/CA) for each node to contend the PN code from the available PN code table and the data slots in each frame used in data channel. Simulation results show that the system performance has been improved.

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