Bluetooth voice access networks

In this thesis we first consider the potential for SCO (Synchronous Connection Oriented) link sharing in Bluetooth-based telephony base stations. A design referred to as the Bluetooth Distributed Voice Access Protocol (DVAP) is introduced. In DVAP, Bluetooth mobiles (BM's) collect connectivity information which is provided to the base station infrastructure. Mobile node migration is then used to reduce blocking when a Bluetooth base station (BBS) is carrying a full load of active SCO links. A simple heuristic referred to as Dynamic Base Station Selection (DBS) is used to make the base station assignment. Simulation results are presented which show that DVAP has better voice call blocking performance than existing Bluetooth base station collaboration designs [XT01]. It is also shown that intelligent base station selection can support much higher levels of traffic loading at a given voice call blocking rate compared to an arbitrary base station assignment.; However, when coverage is such that significant Bluetooth link/base station sharing is possible, SCO packet loss rates are unacceptable. The alternative is to operate such a network using voice over Bluetooth ACL (Asynchronous Connection-Less) links (VoACL) with ARQ retransmission. The use of VoACL is investigated in this thesis for its high capacity voice access. Proper statistical measures of voice loss rate are very important in this type of system, where intermittent interferers may lead to unacceptable worst-case packet loss. A finite windowed loss rate model is used to characterize these networks. Analytic and simulation models show that VoACL can result in acceptable voice packet loss performance compared with SCO voice designs, and that the call blocking rate is about the same for both ACL and SCO systems.; Since Bluetooth strictly defines the maximum number of active slave members in each single piconet to 7, each BBS can only support up to seven voice connections simultaneously. However, with the implementation of a reduced rate of voice codecs in Bluetooth radios, it is possible that each BBS can provide more than 7 voice connections simultaneously. This results in the blocking of all available voice connections beyond that number. Multihop design is developed to solve this limitation. A BM can act as a relaying station in such a network to relay a voice connection between its BBS and another BM. Clearly, a BM increases its power consumption when it acts as a relaying station. Therefore, a power saving scheme is developed to save power consumption over all BM's. The analytic model shows that the power consumption of BM's can be limited by the upper and lower bounds.