Research On Enhancing The Transmission Performance Of Bluetooth And Baseband IC Design

As a short distance wireless communication technology, using in wirelessconnection between mobile device and immovable device, and with the merits of lowpower consumption, low cost, easy networking, qualified for voice transmission,Bluetooth is one of the most rapid growth wireless communication technology. Thispaper studied and analyzed the performance of Bluetooth data throughput such asbluetooth scatternet data throughput, internetwork interference of the piconet、thepolling algorithm and also this paper designed the Bluetooth baseband SoC IC.According to the research from the Bluetooth baseband IC design to up level protocoland the application profile, this paper supplies the good reference for the research ofthe short range wireless communication technology.To enhance the data transmission throughput and anti-interference abilityefficiently, a method of adding DM packet type to the Bluetooth2.0+EDR specificationwas proposed. The packet characteristic of DM was put forward. The relationship ofBluetooth2.0+EDR specification’s DH packet types and new added DM packet typeswith signal-to-noise ratio(SNR) were analyzed in AWGN channel. The simulation resultshows that adding DM packet types to Bluetooth2.0+EDR specification will improvethe anti-interference ability and enhance data transmission throughput greatly inAWGN channel.The method of adding BCH encoding packets to Bluetooth specification waspresented in this paper to improve the performance of Bluetooth data transmission,and then the transmission throughput of new added packet types with BCH encodingwas analyzed. The simulation result shows that adding BCH coding packet to Bluetoothspecification can improve the transmission performance obviously.Taking quasi-static Rayleigh fading channel as the channel model, a Bluetoothdata transmission mathematical model in noisy environments was established in thisthesis. relations between bit error rate and average received signal-to-noise ratio(SNR)were derived for GFSK，π/4-DQPSK and8DPSK modulations modes.The function expressions of packet retransmission probability and averagereceived SNR of ACL packets were put forward in this thesis. The transmissionperformances of ACL packets, including average throughput, average retransmissiontimes and average transmission delay, were investigated through the characteristicsand retransmission probabilities of packets. To reduce the times of retransmission and enhance the performance of Bluetoothbroadcasting in noisy environments, the method of adding BCH encoding packet toBluetooth specification was presented in this thesis. Based on the relationship ofpacket retransmission probability and average received SNR, the adaptive packetselection policy was presented for the packets with BCH encoding and Bluetoothspecification’s own packets in different SNRs, that is selecting proper packet indifferent SNRs to get the least retransmission times and the maximal broadcastingthroughput. The compared result shows that the packets broadcasting performancewith BCH encoding method is much better than that of Bluetooth specification’s ownpackets.There are several kinds of packet types in Bluetooth specification to enhance thedata transmission performance in different noisy channels. The impact of payloadlength on Bluetooth data transmission throughput was obtained. Simulation resultscontained in this thesis can be severed as a good benchmark against researches onhow to enhance Bluetooth data transmission throughput.IEEE802.11b(Wi-Fi) wireless local area network (WLAN) works in the same2.4GHzISM frequency with Bluetooth devices, to research the data transmission performanceof Bluetooth in presence of Wi-Fi, the collision in time and frequency betweenBluetooth and Wi-Fi was analyzed. The mathematical model of Bluetooth data packetsretransmission probability in interfered channel was set up on the basis of datapackets performance analyzing. Then the Bluetooth’s data transmission performancewas induced, including the data transmission throughput and time delay. Simulationwas made and the simulation results present reference to the research of theexistence of Bluetooth and Wi-Fi.The pure round robin polling scheme in Bluetooth specification is inefficient inthroughout and average delay. To improve the performance of Bluetooth piconet, anew dynamic polling scheme based on memory (MBRR) was put forward. This projectis enlightened by the action that ants search for food, the efficiency of the piconet wasraised by increasing the polling times to the slaves which has much more payloads.Meanwhile, this project maintains the fairness of each slave. Comparison was madebetween the performance of PRR, ERR and MBRR schemes. The simulation resultshows that MBRR scheme excels in throughput and delay behavior, and has a goodfairness.At last, Based on the research of Bluetooth baseband protocol, we designed the Bluetooth baseband IP, and with the IP design results of other research team partners,the SOC system of Bluetooth baseband was proposed. According to the software andhardware simuliation platform, the Bluetooth device inquiry function and the ACL andSCO link connection were tested. The flatform of Bluetooth SOC system testing was setup, with help of this flatform the function of Bluetooth data communication wasrealized.