Research Of The MAC Protocol In Ad Hoc Network Based On MIMO Technology

Ad Hoc networks are wireless communication systems with special structure，they don’tdepend on any pre-existing infrastructure, but only mutually cooperation of the nodes withseveral hops, so they can be deployed in complicate environment. However, Ad Hocnetworks are generally subjected to more restrictions than cellular networks due to multi-pathfading and the lack of a fixed network topology, so it is difficult to maintain high throughput.As a key technology of high-speed communication networks of next generation, MIMOsystem is applied to Ad Hoc network. It can improve network throughput under the doublewith not increasing the bandwidth. However, there are still many open questions on how toapply MIMO techniques effectively to Ad Hoc networks such as medium access control(MAC) protocols, but the current protocols are mostly designed for SISO, so the combinationof MIMO transmission with MAC for Ad hoc networks will be the focus of this dissertation.By analyzing on the MIMO technology, there are some key points for combination ofMIMO transmission with MAC design. Parallel RTS Processing MAC (PRP-MAC) wasdetailed in this dissertation, which can be applied to heterogeneous MIMO-based ad hocnetworks. However, when the number of receiving antennas in one link is much larger thanthe other link’s, the throughput is limited greatly. That’s because the number of data streamscan be transmitted must be less or equal to the number of receiving antennas in each link. Tosolve this problem, this paper proposed Extended PRP-MAC (EPRP-MAC), the main featureof this protocol is the transmitter can realize interference-free transmission through precodingtechnology when the receiver does not have enough space to eliminate interference, so thatmore parallel transmissions can occur. The EPRP-MAC follows the framework of PRPprotocol, but the EPRP protocol determines whether to pre-equalization at the transmitterbased on link interference condition, so we use MATLAB to simulate the two protocols underdifferent dynamic range of the number of antennas to carry out a quantitative comparison onnetwork performance, we can see the EPRP protocol has better overall throughput and delayperformance.