september 1999 doc: ieee 802.15-091r0 carlos rios september 13, 1999 a proposal for 802.11b and...

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September 1999September 1999 Doc: IEEE 802.15-091r0Doc: IEEE 802.15-091r0

Carlos RiosCarlos RiosSeptember 13, 1999September 13, 1999

A Proposal for 802.11b and Bluetooth A Proposal for 802.11b and Bluetooth Coexistence in Enterprise EnvironmentsCoexistence in Enterprise Environments

AbstractAbstract

Operational ScenarioOperational Scenario

CoexistenceCoexistence

Obvious QuestionsObvious Questions

Extension to Small BusinessExtension to Small Business

SummarySummary

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September 1999 September 1999 Doc: IEEE 802.15-091r0Doc: IEEE 802.15-091r0

SubmissionSubmission Carlos RiosCarlos Rios

AbstractAbstract

• A scheme for simultaneous, collocated IEEE 802.11High Rate A scheme for simultaneous, collocated IEEE 802.11High Rate DSSS and Bluetooth (BT) communications in environments DSSS and Bluetooth (BT) communications in environments managed by an MIS infrastructuremanaged by an MIS infrastructure– Typically a large enterpriseTypically a large enterprise

• The concept is to guarantee frequency orthogonality at all timesThe concept is to guarantee frequency orthogonality at all times

• Applicable to next generation productsApplicable to next generation products– Bluetooth 2.0 (BTv2), as modification of present protocols is requiredBluetooth 2.0 (BTv2), as modification of present protocols is required– 802.11b APs need configurability, manageability mods also802.11b APs need configurability, manageability mods also

• Some possible implementations require no modification of the Some possible implementations require no modification of the presently envisioned, first generation hardwarepresently envisioned, first generation hardware– ““Just firmware changes…”Just firmware changes…”

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Operational ScenarioOperational Scenario

• Assume an enterprise with installed wired and (2.4 GHz) wireless Assume an enterprise with installed wired and (2.4 GHz) wireless LANs providing high speed connectivityLANs providing high speed connectivity

• Both managed by a common NMS, maintained by the MIS/IT folkBoth managed by a common NMS, maintained by the MIS/IT folk– NMS monitors and configures fixed nodes, APs and mobile clientsNMS monitors and configures fixed nodes, APs and mobile clients– Controls network accessControls network access– Gathers statistics, gauges trends, monitors trafficGathers statistics, gauges trends, monitors traffic

• The MIS department “owns the airwaves”The MIS department “owns the airwaves”– Has the charter to provide reliable, secure, uninterrupted wireless Has the charter to provide reliable, secure, uninterrupted wireless

network access, microwave ovens notwithstandingnetwork access, microwave ovens notwithstanding– Typically engage in “search and destroy” missions to ferret out Typically engage in “search and destroy” missions to ferret out

interfering clandestine WLANs and cordless telephonesinterfering clandestine WLANs and cordless telephones

• To these MIS managers, Bluetooth devices would be decidedly To these MIS managers, Bluetooth devices would be decidedly unwelcomeunwelcome– BT is an excellent 802.11b jammerBT is an excellent 802.11b jammer– Post “No Bluetooth” decals at building entrances?Post “No Bluetooth” decals at building entrances?

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But,But,

• Nobody really wants thatNobody really wants that

• Bluetooth is compelling in the enterpriseBluetooth is compelling in the enterprise– BT enabled PDA connectivity to the internet, corporate email, intranetBT enabled PDA connectivity to the internet, corporate email, intranet– BT enabled laptops in a conference room sharing files, presentation BT enabled laptops in a conference room sharing files, presentation

materials over one or more piconetsmaterials over one or more piconets– BT enabled WAN access independent of the corporate netBT enabled WAN access independent of the corporate net

• Bluetooth Access Points are comingBluetooth Access Points are coming– Complement to the WLAN APsComplement to the WLAN APs– Act as either master or slave in BT piconetsAct as either master or slave in BT piconets– Located in conference rooms, meeting areas, cafeterias and other high Located in conference rooms, meeting areas, cafeterias and other high

traffic areas to provide access to the corporate net, gatewaystraffic areas to provide access to the corporate net, gateways– Are key to Bluetooth and 802.11 coexistence in the enterpriseAre key to Bluetooth and 802.11 coexistence in the enterprise

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Enterprise BT and 802.11 CoexistenceEnterprise BT and 802.11 Coexistence

10/100 BASE10/100 BASE--TT

Ethernet Hub/SwitchEthernet Hub/Switch

NetworkNetworkManagementManagement

SystemSystem

802.11b802.11bAccessAccessPointPoint

802.11b Clients802.11b Clients

BT ClientsBT ClientsBluetoothBluetooth

AccessAccessPointPoint

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Harmonic Coexistence, part 1Harmonic Coexistence, part 1

• Modify the Bluetooth 1.0 air protocols such that the hopping Modify the Bluetooth 1.0 air protocols such that the hopping sequence avoids, using adaptive FH, designated 25 MHz sections of sequence avoids, using adaptive FH, designated 25 MHz sections of the spectrumthe spectrum– Define 5 sets of BT “forbidden FH channels” that happily coincide with Define 5 sets of BT “forbidden FH channels” that happily coincide with

the North American and European non overlapping 802.11b DS (.11bv2) the North American and European non overlapping 802.11b DS (.11bv2) channel spacings (chs 1, 6, 7, 11, 13)channel spacings (chs 1, 6, 7, 11, 13)

– Derive 5 BTv2 “Optional Hop Modes (OHMs)” from these sets, yielding Derive 5 BTv2 “Optional Hop Modes (OHMs)” from these sets, yielding hopping sequences that occupy 59 (84 - 25) channels onlyhopping sequences that occupy 59 (84 - 25) channels only

– Rather than hopping into a “forbidden FH channel” the BTv2 frequency Rather than hopping into a “forbidden FH channel” the BTv2 frequency would be mapped to one of the other 59 “permitted” channelswould be mapped to one of the other 59 “permitted” channels

• Configure the BTv2 and .11bv2 emitters to operate in the Configure the BTv2 and .11bv2 emitters to operate in the complementary OHMs and DS channels at any given timecomplementary OHMs and DS channels at any given time– The .11bv2 signals blithely occupy the 25 Mhz vacated by BTv2The .11bv2 signals blithely occupy the 25 Mhz vacated by BTv2– There are no throughput hits to either wireless networkThere are no throughput hits to either wireless network

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Harmonic Coexistence, part 2Harmonic Coexistence, part 2

• However, need to keep the FCC folks happy with the FH average However, need to keep the FCC folks happy with the FH average time of occupancy requirementstime of occupancy requirements– FH emitters need occupy a minimum 75 channels for no more than FH emitters need occupy a minimum 75 channels for no more than

400 ms total over a 30 second interval400 ms total over a 30 second interval

• So, hop the .11bv2 emitters over the 3 non overlapping US DS So, hop the .11bv2 emitters over the 3 non overlapping US DS channels, switching between them every 10 secondschannels, switching between them every 10 seconds– Existing 802.11 beacon mechanisms support this Existing 802.11 beacon mechanisms support this

• In concert, alternate BTv2 hopping between the corresponding 3 In concert, alternate BTv2 hopping between the corresponding 3 OHMs that provide the frequency orthogonality with the .11bv2 setOHMs that provide the frequency orthogonality with the .11bv2 set

• Compliance with the FCC occupancy time requirements is assured Compliance with the FCC occupancy time requirements is assured with a judicious BTv2 frequency mapping algorithm taken over the with a judicious BTv2 frequency mapping algorithm taken over the 3 nonoverlapping OHMs3 nonoverlapping OHMs– Simplest idea is “shell game” where the 25 OHM1 forbidden Simplest idea is “shell game” where the 25 OHM1 forbidden

frequencies map into those of OHM2, the OHM2 forbidden channels frequencies map into those of OHM2, the OHM2 forbidden channels map into OHM3’s, and then OHM3’s map back into OHM1’smap into OHM3’s, and then OHM3’s map back into OHM1’s

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Obvious QuestionsObvious Questions• How to bind BTv2 and .11bv2 networks in a sensible manner?How to bind BTv2 and .11bv2 networks in a sensible manner?

– Pair BTv2 and .11bv2 APs on a one to one basis, perhaps with only Pair BTv2 and .11bv2 APs on a one to one basis, perhaps with only enough physical separation to avoid desensitization and ACIenough physical separation to avoid desensitization and ACI

– Configure the Bluetooth AP as a “BTv2 Pilot” associated with its “.11bv2 Configure the Bluetooth AP as a “BTv2 Pilot” associated with its “.11bv2 Partner” APPartner” AP

• ““BTv2 Pilot”?BTv2 Pilot”?– Need to preclude activation of full band FH emissions by BT radios Need to preclude activation of full band FH emissions by BT radios

wandering about in their standby state, without a priori knowledge of the wandering about in their standby state, without a priori knowledge of the specific spectrum sharing protocol at any given locationspecific spectrum sharing protocol at any given location

– With no BT nets established, the BTv2 Pilot operates exclusively in Inquire With no BT nets established, the BTv2 Pilot operates exclusively in Inquire mode, issuing continuous, successive pages in order to locate all BT radios mode, issuing continuous, successive pages in order to locate all BT radios in range as they emerge from standby. in range as they emerge from standby. » BTv2 pages need to incorporate OHM data for proper response by waking radiosBTv2 pages need to incorporate OHM data for proper response by waking radios» BTv2 pages will be subject to mapping out of Inquiry Hop Frequency SetBTv2 pages will be subject to mapping out of Inquiry Hop Frequency Set

– BT radios respond to the Pilot, piconets are established and the Pilot BT radios respond to the Pilot, piconets are established and the Pilot remains connected in order to, as a minimum, relay OHM cycling remains connected in order to, as a minimum, relay OHM cycling information to the piconet participantsinformation to the piconet participants

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More Obvious QuestionsMore Obvious Questions• And the “.11bv2 Partner”?And the “.11bv2 Partner”?

– Provides the successive Optional Hopping Mode cycle data (“Next Up, Provides the successive Optional Hopping Mode cycle data (“Next Up, OHM mode 3”) and necessary timing marks (“Engage now”) to the BTv2 OHM mode 3”) and necessary timing marks (“Engage now”) to the BTv2 Pilot, consistent with its own agile channel changes.Pilot, consistent with its own agile channel changes.

• Just how would the OHM and DSSS frequency agility be coordinated?Just how would the OHM and DSSS frequency agility be coordinated?– Best left as an exercise to the implementerBest left as an exercise to the implementer– Likely first option is use the wireline backbone to link paired BTv2 Likely first option is use the wireline backbone to link paired BTv2

and .11bv2 APs. The resulting timing uncertainty due to propagation and .11bv2 APs. The resulting timing uncertainty due to propagation through the network may not be critical if OHMs cycle only every 10 through the network may not be critical if OHMs cycle only every 10 secondsseconds

– Or, implement a short wired connection (RS-232?) between paired APs.Or, implement a short wired connection (RS-232?) between paired APs.

• And coordination of all interacting 802.11APs within one building?And coordination of all interacting 802.11APs within one building?– If organized in the classic non overlapping 3 cell structure, likely have the If organized in the classic non overlapping 3 cell structure, likely have the

NMS centrally coordinate the .11bv2 AP frequency agility, with the same NMS centrally coordinate the .11bv2 AP frequency agility, with the same attendant timing concerns as aboveattendant timing concerns as above

– Maybe OK to not hop 802.11 APs if they are not paired with a BTv2 APMaybe OK to not hop 802.11 APs if they are not paired with a BTv2 AP» Would overlap only 1/3 of the time with a contiguous, hopping .11bv2 AP- the Would overlap only 1/3 of the time with a contiguous, hopping .11bv2 AP- the

throughput hit due to mutual CCA deferrals could be acceptablethroughput hit due to mutual CCA deferrals could be acceptable

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Extension to Small BusinessExtension to Small Business

• Small businesses don’t have MIS departments or sophisticated Small businesses don’t have MIS departments or sophisticated NMS systemsNMS systems

• Are probably more likely than enterprises to want both BT and Are probably more likely than enterprises to want both BT and 802.11 networks on site802.11 networks on site

• Networks are much smaller in scaleNetworks are much smaller in scale

• Possible implementation scenarioPossible implementation scenario– One “master” .11bv2 AP would be configurable to coordinate the One “master” .11bv2 AP would be configurable to coordinate the

frequency agility of its brother 802.11 APs.frequency agility of its brother 802.11 APs.– Hopping coordination propagates from AP to AP through the wired Hopping coordination propagates from AP to AP through the wired

backbone, or also over the air to “Wireless APs” and/or repeatersbackbone, or also over the air to “Wireless APs” and/or repeaters– Frequency coordination propagates to the BTv2 APs via their .11bv2 Frequency coordination propagates to the BTv2 APs via their .11bv2

Partners, as in the enterprisePartners, as in the enterprise

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SummarySummary

• A method for providing simultaneous, collocated enterprise A method for providing simultaneous, collocated enterprise 802.11b and Bluetooth communications was presented802.11b and Bluetooth communications was presented

• Modifications to the existing Bluetooth 1.0 spec are needed to Modifications to the existing Bluetooth 1.0 spec are needed to make it workmake it work

• The existing 802.11b specs needs no changeThe existing 802.11b specs needs no change

• Coordination of 802.11b AP frequency agility is needed at the Coordination of 802.11b AP frequency agility is needed at the network level. These APs would in turn coordinate complementary network level. These APs would in turn coordinate complementary hopping of Bluetooth piconets.hopping of Bluetooth piconets.

• All the above are conceivably implementable without changes to All the above are conceivably implementable without changes to first generation hardwarefirst generation hardware

• An extension to small business environments was also thrown inAn extension to small business environments was also thrown in

september 1999 doc: ieee 802.15-091r0 carlos rios september 13, 1999 a proposal for 802.11b and...

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