Research On Channel Access Algorithms For MBOA UWB MAC Systems

As the development of wireless communication technology, people have more and more requirements to the wireless networks, such as high transmitting rate, ubiquitous, seamless switch and etc. IEEE has developed different standards and technologies according to the various demands and environments. For example, the 802.16 series are focus on the WMAN: Wireless Metropolitan Area Network, the 802.11 series are about the WLAN: Wireless Local Area Network and the 802.15 series are concerned on the WPAN: Wireless Personal Area Network. UWB (Ultra Wide Band) technology belongs to the 802.15 series. It outperforms Bluetooth in its high transmission rate, low power consuming, strong anti-interference ability and compatibility. Therefore, it's the most promising technology for the next generation WPAN standard. At present there are two camps of UWB standards: MBOA (Multi-band ODFM Alliance) camp which is led by Intel and TI, DS-UWB (Direct Sequence-UWB) camp led by Motorola and its fellows. These two camps have developed their specifications for both Physics and Mac Layer respectively. This dissertation concentrates on the performance analysis of channel access and resource allocation algorithms in MBOA-UWB MAC standard. MBOA-UWB Mac layer is a distributed Ad Hoc structure where time is divided into fixed length super frames. Every device coordinates with its neighbors and accesses the channel using either contention based CSMA scheme or reservation based scheme. In reservation scheme, the sender should reserve corresponding free time slots for the traffic requirements. However, there are lots of available time slots distributed throughout the super frame and the sender should also take into account the affectation of its neighbors. Therefore, the transmitter has to regulate its reservation scheme for certain requirements, such as maximum throughput and minimum end-to-end delay, so that it can improve both the local and overall network utilization performance. This dissertation proposes a mathematics model based on embedded Markov chain which can accurately predict the end-to-end delay performance and packet loss rate under different reservation schemes. Also we could estimation the performance in the transmitter so that we could guide the channel access reservation scheme. At last, we deduce the optimal reservation scheme under MBOA-UWB MAC specification. All the formulas are under precisely derivation and simulation validation.