Error Rate Results of OFDM from Bluetooth Interference 11/29/2018 doc.: IEEE 802.11-00/xxx May 2001 Error Rate Results of OFDM from Bluetooth Interference John Terry, Ph.D. (john.terry@nokia.com) Nokia Research Center Irving, TX J. Terry, Nokia Sunghyun Choi, Philips Research

Outline Motivation Model used for analysis and simulation May 2001 Outline Motivation Model used for analysis and simulation Simulation results Conclusions J. Terry, Nokia

Motivation for Analysis May 2001 Motivation for Analysis March 2001, IEEE802.11 TGg meeting considerable discussion took place concerning the performance of PBCC and OFDM in the face of Bluetooth (BT) interference Nokia was one of the four founding members of Bluetooth SIG and has a considerable stake in the technology Nokia currently has IEEE802.11b products in the 2.4 GHz band with product road maps for both 2.4 and 5 GHz IEEE802.11 WLAN products Both BT and IEEE802.11 are important to Nokia J. Terry, Nokia

May 2001 Questions Does OFDM have any special properties to cancel BT interference? What is the packet loss rate in the face of BT pico nets? What benefit is provided by using erasures? How much does the performance of OFDM system further degrades in the presence of multiple BT interferers? Do the sychronization algorithms used at the receiver have an impact on the erasures' performance? What are the SIR and SNR levels where the all packets are loss? J. Terry, Nokia

Approach to Answer Question May 2001 Approach to Answer Question Focus on effects of BT interference on OFDM first as NRC Dallas has detailed simulation models down to the fixed point level for IEEE802.11a “Off the shelf” OFDM receiver design based upon IEEE802.11a is used for baseline (no Barker preamble) Performance without any special interference canceling algorithms are applied in the OFDM receiver for simulation study for various SIR levels Performance with erasures specified at the receiver. J. Terry, Nokia

BT Interference Model GFSK modulation operating at 1 Msps May 2001 BT Interference Model GFSK modulation operating at 1 Msps BT=0.5 with 1600 hops/sec Power levels simulated were [-20 -10 0 10 20] dB 11 Erasures are used Total of 11*312.5KHz=3.44 MHz of spectrum is removed 1 and 3 BT pico net environments are examined Phop=17/79=21.5% for 1 BT Phop ~ 50% for 3 BT Extracted from document IEEE 802.11-01/061r0 J. Terry, Nokia

Symbol Constellation w/ 0 dB BT Interference May 2001 Symbol Constellation w/ 0 dB BT Interference J. Terry, Nokia

Symbol Constellation w/ 0 dB BT Interference and Erasures May 2001 Symbol Constellation w/ 0 dB BT Interference and Erasures J. Terry, Nokia

802.11a Simulation Parameters May 2001 802.11a Simulation Parameters 24 Mbps mode 16 QAM, rate 1/2 convolutional coding, and bit Interleaving 48 Mbps mode 64 QAM, rate 2/3 punctured convolutional coding, and bit interleaving Includes packet detection, frequency offset correction, channel estimation/correction, fine time estimation Channels: Exponential Decay 5 tap Rayleigh channel Packet Length of 100 Bytes Subcarrier spacing 312.5 KHz J. Terry, Nokia

Scenario #1 Environment: 1 BT pico net Channel: 5 tap Rayleigh channel May 2001 Scenario #1 Environment: 1 BT pico net Channel: 5 tap Rayleigh channel SIR: [20, 10, 0, -10, -20] Data Rate: 24 Mbps J. Terry, Nokia

24 Mbps PER Simulations May 2001 J. Terry, Nokia 10 11 12 13 14 15 16 17 18 19 20 -3 -2 -1 Packet Error Rate, IEEE802.11a 24Mbit mode, Rayleigh 5 tap PER BT Interference SIR= -20 dB No Interference BT Interference SIR= -10 dB Bluetooth Interference SIR=0 dB BT Interference SIR=10 dB BT Interfernce SIR=20 dB SNR J. Terry, Nokia

Scenario #2 Environment: 1 BT pico net with Erasures May 2001 Scenario #2 Environment: 1 BT pico net with Erasures Channel: 5 tap Rayleigh channel SIR: [20, 10, 0, -10, -20] Data Rate: 24 Mbps J. Terry, Nokia

24 Mbps PER Simulation May 2001 J. Terry, Nokia 10 11 12 13 14 15 16 17 18 -3 -2 -1 SNR PER Packet Error Rate, IEEE802.11a 24Mbit mode, Rayleigh 5 tap BT Interference SIR= -20 dB BT Interference SIR= -10 dB BT Interference SIR= 0 dB BT Interference SIR= 20 dB Perfect Sync BT Interference SIR= 20 dB No Interference J. Terry, Nokia

Channel: 5 tap Rayleigh channel May 2001 Scenario #3 Environment: 1 BT pico net comparison of erasure w/perfect and imperfect synchronization Channel: 5 tap Rayleigh channel SIR: [10, 0] Data Rate: 24 Mbps J. Terry, Nokia

24 Mbps PER Simulation May 2001 J. Terry, Nokia 10 11 12 13 14 15 16 17 18 19 20 -2 -1 SNR PER Packet Error Rate, IEEE802.11a 24Mbit mode, Rayleigh 5 tap BT Interference SIR= -10 dB Perfect Sync BT Interference SIR= -10 dB BT Interference SIR= 0 dB Perfect Sync BT Interference SIR= 0 dB J. Terry, Nokia

May 2001 Scenario #4 Environment: 1 BT pico net comparison with and without Erasures Channel: 5 tap Rayleigh channel SIR: [20, 0, -20] Data Rate: 24 Mbps J. Terry, Nokia

24 Mbps PER Simulations May 2001 10 11 12 13 14 15 16 17 18 19 20 SNR -2 -1 SNR PER Packet Error Rate, IEEE802.11a 24Mbit mode, Rayleigh 5 tap BT Interference SIR= -20 dB w/Erasures BT Interference SIR= -20 dB BT Interference SIR= 0 dB w/Erasures BT Interference SIR= 0 dB BT Interference SIR= 20 dB w/Erasures BT Interference SIR= 20 dB J. Terry, Nokia

Scenario #5 Environment: 1 and 3 BT pico net comparison May 2001 Scenario #5 Environment: 1 and 3 BT pico net comparison Channel: 5 tap Rayleigh channel SIR: [20, 0, -20] Data Rate: 24 Mbps J. Terry, Nokia

PER vs # BT Interference May 2001 PER vs # BT Interference 10 11 12 13 14 15 16 17 18 19 20 -2 -1 SNR PER Packet Error Rate, IEEE802.11a 24Mbit mode, Rayleigh 5 tap BT3 Interference SIR= -20 dB BT Interference SIR= -20 dB BT3 Interference SIR= 0 dB BT Interference SIR= 0 dB BT3 Interference SIR= 20 dB BT Interference SIR= 20 dB J. Terry, Nokia

Scenario #6 Environment: 1 BT pico net Channel: 5 tap Rayleigh channel May 2001 Scenario #6 Environment: 1 BT pico net Channel: 5 tap Rayleigh channel SIR: [20, 10, 0, -10, -20] Data Rate: 48 Mbps J. Terry, Nokia

48 Mbps PER Simulation May 2001 J. Terry, Nokia 19 20 21 22 23 24 25 26 27 10 -3 -2 -1 SNR PER Packet Error Rate, IEEE802.11a 48Mbit mode, Rayleigh 5 tap BT Interference SIR= -20 dB No Interference BT Interference SIR= -10 dB Bluetooth Interference SIR=0 dB BT Interference SIR=10 dB BT Interfernce SIR=20 dB J. Terry, Nokia

May 2001 Conclusions Bluetooth interference severely degrades the PER performance of OFDM systems for SIRs of 10 dB and smaller. An error floor equals to the probability that a BT hops in-band occurs. Erasures provide very little additional protection when all the receiver algorithms are used. Higher data rates such as 48 Mbps are more susceptible to the interference than lower rates. More sophiscated interference suppression techniques are needed to improve performance. J. Terry, Nokia