By N.Golmie… Presented by: Sushanth Divvela 1"Agenda' Introduction  WPAN  WLAN  Simulation Models  Simulation results  Concluding remarks 2"Introduc.on' Coexistence of WPAN and WLAN  Performance evaluation WLAN and Bluetooth when operating in close proximity.  Results are based on MAC, PHY and Wireless channel  Results are done using analysis, simulation and experiment results. 3"Bluetooth' Short Range (0-10m) wireless technology  Operates in the ISM frequency (2.402 GHz-2.483GHz)  79 RF channels of 1 MHz  Antenna power is 1 mW  Binary Gaussian Frequency Shift Keying(GFSK)  Data rate 1 Mbps  TDM is used to divide the channels into 625 micro sec slots 4" Piconet" Master"and"Slave" The"Slave"always"follows"the"Master"packet"transmission" Slaves"in"the"piconet"synchronize"their"timing"and"frequency"once"the"connection"is"established"5"The"two"types"of"link"connections"":" Synchronous"Connection‐Oriented"(SCO)"‐ Symmetric"Point"–Point"conection"between"a"master"and"slave"where"master"sends"an"SCO"packet"in"one"TX"slot"at"regular"time"intervals,defined"by"Tsco"time"slots." Asynchronous"Connection‐Less"(ACL)"‐ Asymmetric"Point"–"Point"connection"between"a"master"and"slave"in"the"piconet"which"uses"ARQ"for"lost"packets."6" Both"ACL"and"SCO"have"the"same"frame"format"" It"consists"of"a"72‐bit"access"code"used"for"message"identification"and"synchronization,"a"54‐bit"header"and"a"variable"length"payload"that"contains"either"a"voice"or"a"data"packet"" A"repetition"code""is"applied"to"the"header,"and"a"block"code"is"applied"to"the"access"code"so"that"up"to"13"errors"can"be"detected"and"6"can"be"corrected." Uncorrected"errors"in"the"header"and"accesscode""lead"to"packet"drop." HV"packets"do"not"have"CRC"in"the"payloaad."7"IEEE'802.11b' The IEEE 802.11 standard defines both the physical (PHY) and medium access control (MAC) layer protocols for WLANs  The three different PHY specifications: frequency hopping (FH) spread spectrum, direct sequence (DS) spread spectrum, and IR.  The transmit power for DS and FH devices is defined at a maxi-mum of 1 W and the receiver sensitivity is set to −80 dBmW. Antenna gain is limited to 6 dB maximum. 8" The"basic"data"rate"for"the"DS"system"is"1"Mbit/s"encoded"with"differential"binary"phase"shift"keying"(DBPSK)."" Higher"rates"of"5.5"and"11"Mbit/s"are"also"available"using"techniques"combining"quadrature"phase"shift"keying"and"complementary"code"keying"(CCK)" All"the"systems"use"22"MHz"channels"9"MAC'layer' Coordinate the communication between stations and control the behavior of users who want to access the network.  The Distributed Coordination Function (DCF), which describes the default MAC protocol operation, is based on a scheme known as carrier-sense, multiple access, collision avoidance (CSMA/CA).  Both the MAC and PHY layers co- operate in order to implement collision avoidance procedures 10" Carrier sense is used to determine if the channel is busy.  A virtual carrier sense mechanism is also provided at the MAC layer. It uses the request-to-send (RTS) and clear-to- send (CTS) message exchange to make predictions of future traffic 11"! Simula(on!model' The PHY, and MAC layers developed in C and OPNET  For interference to occur, the packets must overlap in both time and frequency.  The bit errors in the packet depends on : (1) the signal-to-interference ratio (SIR) and the signal-to-noise ratio at the receiver (2) the type of modulation used by the transmitter and the interferer (3) the channel model 12" MAC"model:" Bluetooth"hopping"pattern"algorithm"is"implemented"using"OPNET." The"MAC/PHY"interface"module"is"used"for"802.11b"in"the"OPNET"library." "PHY"model:" The"receiver"at"the"Bluetooth"is"noncoherent"limiter‐discriminator"receiver." The"802.11b"uses""CCK"reciever." Channel"model:" Line"of"Sight"propagation"for"first"8m"and"a"propagation"exponent"of"3.3"for"distances"over"8m." AWGN"is"used"to"model"noise"at"recievers"13"Simula.on''Results' Factors"effecting"interference"‐ WLAN"transmission"power"‐ Offered"load"‐ Bluetooth"traffic"type"‐ Bluetooth"transmission"power" Realistic"interference"topologies"‐ WLAN"device"in"the"midst"of"Bluetooth"Piconets"‐ WLAN"access"point"acting"as"a"source"14" Scenaio"1:"The"WLAN"mobile"is"the"generator"of"data"and"WLAN"AP"is"the"sink." Scenario"2:"The"traffic"is"generated"at"the"AP"and"received"at"the"WLAN"mobile." For"Bluetooth""voice"and"data"applications"are"considered" Voice"–"64kbps"using"HV1"packet"encapsulation" The"packet"interarrival"time"is"Tb"is"exponentially"distributed." For"WLAN""11"Mbps"is"used"."The"packet"payload"is"fixed"to"12000"bits"and"vary"the"offered"load."15" WLAN"transmitted"power:" Saturation"around"10"mW" Between"1"mW"and"5"mW""a"small"change"in"WLAN"power"triples"the"Bluetooth"packet"loss." As"offered"load"increases"the"packet"loss"increases" Voice"has"the"lowest"packet"loss" The""packet"loss"decreases"as"the"WLAN"transmitted"power""increases"." Between"1"and"5"mW"there"is"a"bump"due"to"closed‐loop"interfernce."16"'Probability'of'packet'loss'for'Bluetooth'slave'17"''''''''''''''''Scenario'1''''''''''''''''''Scenario'2'18" Probability"of"packet"loss"for"WLAN"mobile"device"" The"packet"loss"decreases"as"the"WLAN"transmited"power"increases." Between"1"and"5"mW"there"is"a"bump""this"is"due"to"closed"loop"interference." Probability"of"packet"loss"for"WLAN"source" The"packet"loss"for"WLAN"does"not"change." Increase"in"power"does"not"necessarily"improve"the"performance."19"Offered"Load:" "In"scenario"1":"Bluetooth"is"interferer"and"WLAN"trannsmission"power"is"fixed"at"25"mW" The"WLAN"packet"loss"is"proportional"to"the"bluetooth"offered"load." It"also"depends"on"the"packet"sizes"of"both"systems." The"short"Bluetooth"voice"packets"lead"a"less"packet"loss"for"Bluetooth"but"cause"more"interference"for"WLAN."20"Realis.c'interference'topologies' Topology"1:" When""WLAN"system"is"not"operating"the"Bluetooth"packet"loss"is"negligible"