HIPERLAN

Tim Wilkinson

HP Labs Europe

What is HIPERLAN?

HIPERLAN - HIgh PErformance RadioLANHIPERLAN is a new standard for Radio

LANs developed in Europe by ETSIHIPERLAN is an interoperability standard

which specifies a common air interfaceMAC and PHY layers in OSI modelHIPERLAN will be a family of standardsHIPERLAN 1 is described in detail

HIPERLAN - reference model

Medium Access Control(MAC) Sublayer

Channel Access Control(CAC) Sublayer

Physical (PHY) Layer

Application Layer

Presentation Layer

Session Layer

Transport Layer

Network Layer

Data Link Layer

Physical Layer

higher layer protocols

OSIReference Model

HIPERLANReference Model

Early wireless LANs operating in theISM bands (900MHz and 2.45GHz)Low data rate (~1Mbps) - an indirect result of the FCCspread spectrum rules part 15.247Severe interference environment - from unlike wirelessLANs and other ISM band systemsLack of standards - IEEE 802.11 was initiated to satisfythis need but it was taking time to developETSI set up RES10 to develop a standard thatwould be equal in performanceto wired LANs such as Ethernet

Origins of HIPERLAN

HIPERLAN 1 - history

O ETSI set up RES10 group - mid 1991O RES10 start work on standard - early 1992O CEPT allocate spectrum - early 1993O RES10 complete draft standard - mid 1995O ETSI publish final standard - late 1995O RES10 start work on type approval - early 1996O HIPERLAN passes public enquiry - mid 1996

HIPERLAN 1 - spectrum

CEPT identified vacant spectrum at 5GHz5.00-5.25GHz was allocated worldwide

to aviation authorities on a primary basisfor MLS but only 5.00-5.15GHz was usedCEPT allocated 5.15-5.25GHz to

HIPERLAN on a secondary basis with itsstatus as non-interference, non-protectedAn extension of the band from 5.25-

5.3GHz is available in most countries

HIPERLAN - applicationsEarly ideas

with infrastructure without infrastructure

Others include - many vertical applications, wireless dockipublic access to the NII, home networks

O Short range - 50mLow mobility - 1.4m/sNetworks with and without infrastructureSupport isochronous trafficaudio 32kbps, 10ns latencyvideo 2Mbps, 100ns latencySupport asynchronous trafficdata 10Mbps, immediate access

HIPERLAN 1 - requirements

High transmission rate - 23.5294MbpsModulation - non diff GMSK, BT = 0.3Error control - FEC, BCH(31,26)Packet failure rate - 0.01 (4160 data bits)Low transmission rate - 1.470588MbpsModulation - FSK, freq dev = 368kHzChannelisation - 5 channels, 5.15-5.30GHzTransmit power - +10, +20, +30dBmReceive sensitivity - -50, -60, -70dBm

HIPERLAN 1 PHY - specifications

HIPERLAN 1 PHY - packets

SYNCH SEQUENCE450bits

DATA BLOCK496 bits

LOW RATE HEADER35bits (560bits)HEADER DATA BLO C

496bits

LOW RATE 1.5Mbps HIGH RATE 23.5Mbps

DATA PACKET

ACK PACKET

LOW RATE ACK23bits (368bits)

NO MAC HEADERIMMEDIATE TRANS

LOW RATE 1.5Mbps

1-47 BLOCKS

HIPERLAN 1 - modem optionsco

mpl

exity

performance

DIFFDET

COHERENTDEMOD

ADVANCEDDIVERSITY

DFE

MLSE

dock

ing

room floor

A HIPERLAN can only use one ChannelThere is no mechanism for changing channelAntenna diversity an option but...Must use same antenna for CCAand transmission for correct MAC functionMust reduce transmit power by antenna gainto maintain EIRP as specified by CEPTPower saving with...Low rate header for modem power savingPower saving cycle strategies sleep/wake modes

HIPERLAN 1 PHY - quirks

Fully distributed MACNetworks with and without infrastructurePermits multi-hop relaying via neighboursBased on LBT - uses CCAwith adaptive thresholdEY-NPMA - Elimination Yield Non-pre-emptiveMultiple AccessPrioritiy assertion using listen-talkContention resolution using talk-listenImmediate packet acknowledgment

HIPERLAN 1 MAC - concept

HIPERLAN 1 MAC - hidden nodes

tx

rxcommunication

range

sense/interferencerange

MAC avoids this

tx

HIPERLAN 1 MAC - function

Station 1

Station 2

Station 3

Station 4

Time

data packet

s tops

stops

stops

prioritisa tion contention transmission

Listen

Ta lk

Listen

Listen

Listen

Ta lk

Ta lk

Ta lk

Prioritisation1-5 slots of 168bits (talk)ContentionElimination - 0-12 slots of 212bits (talk),1 slot of 256bits (listen), prob(talk-listen) = 0.5Yield - 0-9 slots of 168bits (listen), prob(n) = 0.1Tx to Rx turn around time 6 µs256 contenders, 3.5% collision probabilityTotal of 0-5152bits (0-219 µs) MAC header

HIPERLAN 1 MAC - phase

Priority is a function of lifetime and user priority

HIPERLAN 1 MAC - priority

NORMALISEDRESIDUALLIFETIME

HIGHUSER

DEFINEDPRIORITY

LOWUSER

DEFINEDPRIORITY

NRL < 10ms 0 110ms < NRL<

20ms1 2

20ms < NRL <40ms

2 340ms < NRL <

80ms3 4

NRL > 80ms 4 4

If lifetime expires packet is discarded in theMAC

Either best effort latency for isochronoustraffic

Or best effort integrity for asynchronous traffic

Simulations show that the HIPERLAN MAC cansimultaneuosly support25 audio links @ 32kbit/s, 10ms delivery25 audio links @ 16kbit/s, 20ms delivery1 video link @ 2Mbit/s, 100ms deliveryAsynch file transfer @ 13.4Mbit/s

HIPERLAN 1 MAC - performance

Two European collaborative projectsLAURA - not fully standards compliantDemonstrated some conceptsNo ASICs developedHIPERION - fully standards compliantASICs designed for...RF MCM with GaAs and Si by GPSModem, Codec, D/A, A/D by AppleMAC controller by ARM

HIPERLAN 1 - testbeds

HIPERLAN 2 - WATM

Idea is to be compatible with ATM– Support QoS guarantees– Efficiently handle ATM cells

Requires additional spectrum in EuropeSharing rules under development by

WINForum for NII/SUPERNET bandin the US aim to support

– HIPERLAN 1 and HIPERLAN 2This effort involves interaction between

– ETSI RES10, WINForum, ATM Forum

HIPERLAN family (ETSI RES10)

DLC

PHY(5 GHz)

20 + Mb/sec

MAC

PHY(5 GHz)

20 + Mb/sec

HIPERLANType 1

Wireless LAN

HIPERLANType 2

Wireless ATMIndoor access

DLC

PHY(17 GHz)

150 + Mb/sec

HIPERLANType 4

Wireless ATMInterconnect

PHY(5 GHz)

20 + Mb/sec

DLC

HIPERLANType 3

Wireless ATMRemote Access

HIPERLAN vision (ETSI RES10)

ATMpremisesswitch

Other networks

Otherlocalconnections

wirelessaccesspoint

wirelessaccesspoint

wirelessaccesspoint

5 GHz HIPERLAN Type 1

5 GHz Type 2

5 GHz Type 2 5 GHz Type 1

17 GHz, Type 4

5 GHz Type 3

wirelessterminationpoint

localconnections