Improving Bluetooth EDR Data Throughput Using FEC and Interleaving Ling-Jyh Chen*, Tony Sun**, Yung-Chih Chen* *Institute of Information Science, Academia Sinica **Dept. of Computer Science, UCLA Introduction Wireless communication is inherently vulnerable to errors. Wireless channel errors are usually bursty and dependent in occurrences rather than independently/ identically distributed. Some robust link layer transmission schemes are required. Contribution We propose three link layer enhancements for Bluetooth v2.0 Adaptive Packet Type (APT) FEC coding Interleaving FEC (IFEC) The proposed solutions are applicable to other wireless technologies. Outline Bluetooth Overview Proposed Link Layer Enhancements Simulation Results Conclusion Bluetooth Overview The “enabler” of Personal Area Network (PAN) Low power, low cost, and smaller chips Packet Mode FEC Size (bytes) 17 121 Length (slots) 1 3 Asymmetric Throughput (kbps) 108.8 387.2 108.8 54.4 DM1 DM3 yes yes DM5 DH1 DH3 yes no no 227 27 183 5 1 3 477.8 172.8 585.6 36.3 172.8 86.4 DH5 no 339 5 723.2 57.6 Bluetooth packet types DH: Stop and Wait ARQ DM: ARQ as well as FEC codes FEC coding scheme: (15, 10) Shortened Hamming code Able to correct single bit error in each block. Bluetooth Enhanced Data Rate (EDR) EDR does not provide FEC enabled packet types (ie., no DM series types) Proposed Link Layer Enhancements 1. Adaptive Packet Type (APT) 2. 3. FEC coding Interleaving FEC (IFEC) Enhancement (I): APT Adaptive T: Packet Type (APT) Determine optimal packet type Theoretical Data throughput s: packet size/bits b: bit error rate n: packet length in Bluetooth slots p: packet error rate Enhancement (I): APT (Con’t) Enhancement (II) : FEC Propose to apply FEC to Bluetooth EDR Called 2DM1/3/5 & 3DM1/3/5 (15,10) shortened Hamming code that is able to correct single bit error Packet Error Rate : ( p: packet error rate, b: bit error rate s: packet size/bits ) Enhancement (II) : FEC (Con’t) Enhancement (III) – IFEC Wireless errors are mostly bursty in presence, previous techniques should be modified. Burst Error Model (aka Gilbert-Elliott model) Pbg Pgg Good Pgb Bad Pbb 1 Pbb Pg 1 Pbb Pgb Pb Pgb 1 Pbb Pgb Propose Interleaved FEC (IFEC) coding Called DMI 1/3/5, 2DMI 1/3/5, and 3DMI 1/3/5 Enhancement (III) – IFEC (Con’t) FEC coding Interleaved FEC coding Simulation Results Gilbert-Elliott model: Pgb= 0.005, Pbb from 0.9 to 0.9999 FEC coding IFEC coding Conclusion We proposed three link layer enhancement techniques (APT/FEC/IFEC) for BT EDR. We verified the proposed techniques using simulation. The proposed solutions are applicable to other wireless technologies. Thank you !
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