Improving Bluetooth EDR Data Throughput Using FEC and Interleaving

							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 !