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Multi-Radio Coexistence: Co-Located Coexistence Class

Document Number: IEEE C80216m-09/559Date Submitted: 2009-02-24Source: Jing Zhu, Aran Bergman, jing.z.zhu@intel.com

Intel Corporation Re: 8.x IEEE 802.16m Air-Interface Protocol Structure: Multi-Radio CoexistenceBase Contribution: N/APurpose: to be discussed and adopted by TGm AWDNotice:

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Voice: +1-503-2647073Email: jing.z.zhu@intel.com

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Outline

• Co-Located Coexistence Class – overview– BS scheduling behavior – improvements over Rev2

• Proposed AWD Outline• Back Up

– co-ex usage scenarios

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Co-Located Coexistence (CLC) Class: Overview

• Fundamental– separate 802.16m and non-802.16m activities in time domain

(enhancing the Rev2 co-ex feature: PSC-based CLC)

• Definition– AMS conducts pre-negotiated periodic absences from the serving

ABS, and the time pattern of such periodic absence is referred by ABS and AMS as Co-Located Coexistence (CLC) class.

• Requirement– mandatory for ABS, optional for AMS

• Parameter– active interval / ratio / period, starting time, number of active classes

• Signaling– capability notification: CLC Limits TLV (REG-RSP)

– activation / deactivation: MOB_CLC-REQ / MOB_CLC-RSP

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Comparison of CLC Classes

Type I Type II Type III

Targeted non-16m radio activities

Bluetooth eSCO, Wi-Fi beacon, …

Bluetooth ACL, Wi-Fi data, …

Bluetooth page/inquiry, Wi-Fi passive scan, …

Unit of Active Interval subframe subframe second*

Unit of Active Ratio % % %

Unit of Active Period microsecond frame second

Unit of Starting Time subframe subframe frame

Owner of Starting Time AMS ABS ABS

*: 1 second = 200 frames

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BS scheduling behavior

• CLC Limits• Latency Limit• MAP and HARQ timing • Synchronous Allocation • SFH, Scan, Sleep, Idle, and HO

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CLC Limits

– BS shall accept a new CLC class request, and honor it (i.e. not unsolicited deactivate it after activation) if the CLC class meets the CLC Limits, and may reject it otherwise

– CLC limits shall be configured according to the above table to ensure the basic support for multi-radio co-ex

k-th active interval

k+1-th active interval

CLC active interval

CLC active period

CLC active ratio = CLC active interval

CLC active period

CLC LimitsMaximum Number of Active Classes of the Type

Maximum Active Ratio

Maximum Active Interval

Type I > or = 1 > or = 5% > or = 5ms

Type II > or = 1 > or = 30% > or = 40ms

Type III 1 1% 3 second

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Latency Limit

• The Maximum Latency parameter of an active service flow shall be guaranteed even if a CLC class is active

– Maximum Latency: the maximum interval between the entry of a packet at the CS and the forwarding of the SDU to its Air Interface.

• Latency Limit (s): the minimum value of the Maximum Latency parameters of all active service flows of the AMS

– Latency Margin (d) provides additional time for meeting Maximum latency requirement (d= 10ms)

DL UL

MAP Data ACKCLC Active Interval (t)

d + t s

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MAP and HARQ timing

DACK DACK

FDDDDL-MAP

DL

UL

DACK DACK

TDDDDL-MAP

•DACK = 4 and DDL-MAP = 1 (or 0) •UL MAP relevance not considered

CLC active interval CLC inactive interval w/o 16m data

• ABS shall not schedule an allocation, if Assignment IE (MAP), Data, or/and ACK of the allocation overlaps with an CLC active interval,

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Synchronous Allocation

Data Nack

Overlap with CLC active interval

Data Nack Data Nack Data Ack

• ABS and AMS shall cancel a synchronous allocation locally if its data or/and ACK overlaps with an CLC active interval that is no longer than a frame, and reschedule it after the end of the CLC active interval.

• How to indicate the rescheduled allocation?– Option 1: dynamic rescheduling (new Assignment IE)

• Pro: lower latency ; Con: control overhead

– Option 2: static rescheduling (next available subframe)• Pro: no control overhead; Con: higher latency (with the same subframe index)

Dynamic Rescheduling

Static Rescheduling (with the same subframe index)

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SFH, Scan, Sleep, HO, and Idle • Super Frame Header

– super frame header may overlap with CLC active interval• AMS / ABS should set the starting time of a CLC class to avoid SFH

as much as possible.

• Scan Mode– scan interval may overlap with CLC active interval

• AMS locally decides whether to perform co-ex or .16m scan

• Sleep Mode– unavailable interval may overlap with CLC active interval

• AMS may use it as additional duty cycle for co-ex

• Handover – locally suspend all active CLC classes before HO starts, and

resume them after HO completes

• Idle Mode– locally deactivate all active CLC classes after entering idle mode

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Improvements over Rev2• Efficiency

– granularity is fixed to frame, e.g. 5ms, and has a direct impact on the efficiency of TDM-based CLC operation, particularly when radio transmissions take less than 5ms

solution: reduce granularity to subframe (617us)• Flexibility

– MS determines CLC pattern, giving little flexibility for BS to adjust according to network condition

solution: allow BS to determine the starting time– CLC period has to be the integer number of frames, and may not suitable to some

application. solution: use microsecond as the unit for period

• Manageability – BS has no way to manage the impact of TDM operation on WiMAX performance solution: CLC limits

• Scalability – only one PSC is allowed active at any given time per MS, and difficult to support multiple

radios / applications. solution: allow multiple classes and multiple types

• Compatibility – power save needs to be disabled when CLC is active

• sleeping pattern is determined by 802.16m traffic • CLC pattern is determined by co-located non 802.16m traffic

solution: CLC class operation independent of sleep mode

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Proposed AWD Outline for Multi-Radio Coexistence

15.2.x Multi-Radio Coexistence

15.2.x.1 Co-Located Coexistence Class

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Back Up

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Co-Ex Usage Examples

• Bluetooth headset – eSCO– page/inquiry

• Wi-Fi – Beacon Listening – Active Scan – Wireless Peripheral – Wireless P2P– Wi-Fi/WiMAX HO

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Bluetooth: eSCO + 16m TDD

1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 56

1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8

1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5

1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8

Max BT Retries = 0, CLC Active Ratio = 17%

Max BT Retries = 1, CLC Active Ratio = 9%

Max BT Retries = 2, CLC Active Ratio = 5%

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1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5 6 1 2 3 4 5

1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8

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Bluetooth Slot

.16m subframe

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Bluetooth: Page / Inquiry

• Bluetooth Page/Inquiry– Transmit in one Bluetooth slot every 2 slots for at least 2.56

seconds • each slot is 625 us

supported by Type III CLC class

(CLC active interval > 2.56s)

• Bluetooth Page/Inquiry Scan– Listen for 11.25ms (scan window) for every 1.28 secondssupported by Type II CLC class

(CLC active ratio = 1 superframe / 64 =1.6%)

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Wi-Fi: Beacon Listening

Frame Frame nn n+1n+1

Wi-Fi Beacon

… … … …

n+20n+20 n+21n+21

Wi-Fi Beacon

102.4ms

7 subframes (~5ms)

.16m subframe

Wi-Fi

•CLC Active Interval: 5ms•Beacon transmission time < 5ms

•CLC Active Period: 102.4ms•Beacon Interval = 102.4ms

•CLC Active Ratio: < 5%

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Wi-Fi: Active Scan

70ms (.16m) 30ms (Wi-Fi) 70ms (.16m) 30ms

100ms*

Wi-Fi active scan

Prob-Req

Prob-RSP

ACKSTA

AP

•CLC Active Interval: 30ms•Wi-Fi STA usually needs ~30ms to complete one active scan operation

*: other configurations are possible

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Wi-Fi: (Low-Latency) Wireless Peripheral•CLC Active Interval: 2 subframes•CLC Active Period: 5ms•CLC Active Ratio: 25%

Available Time Ratio for .16m Data Allocations

67% 100%

DL UL

60% 67%

50% 50%

67% 60%

100% 67%

DL: UL CLC Active Pattern*

6: 2

5: 3

4: 4

3: 5

2: 6

*: only example, and other configurations possible

.16m data allocation time 50%

Unavailable due to HARQ timing

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General Mouse

Wireless Keyboard

Voice Quality Headset

CD Quality headphones

Throughput Req. 8kbps 8kbps 256 kbps 384kbps

Latency Req. < 10ms < 50ms < 30ms < 100ms

Period 10ms 20ms 20ms 20ms

Bytes per period < 10 <20 640 960

Tx Time*

(11g-only, 6Mbps)

189us 201us 1029us 1453us

x 2 (+ 1 re-transmission) 378us 402us 2058 2906us

CLC Active Interval (subframes)

1

(0.6ms)

1

(0.6ms)

4

(2.4ms)

5

(3.0ms)

CLC Active period

(frames)

2 4 4 4

CLC Active Ratio 7% 4% 13% 16%

*: no contention from other Wi-Fi STAs;

Wireless Peripheral (cont’d)

< 30%

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Usages

Voice Projection File Sharing

Wireless Display

480p

Sync-Go

Throughput Req. (Mbps) 0.1 6 16 17 67

Maximum 802.11n PHY Rate (Mbps)

65 (1x2, 20Mhz) <1% 17% 44% 47% N/A

135 (1x2, 40Mhz) <1% 8% 22% 23% 89%

195 (3x3, 20Mhz) <1% 6% 15% 16% 62%

405 (3x3, 40Mhz) <1% 3% 8% 8% 30%

< 30%

Traffic Load of Wireless P2P (Peer-to-Peer) Usages

Latency Req. for the above applications: > 10ms

Maximum Throughput = PHY Rate x (1 – PER* ) x MAC Efficiency* Traffic Load = Throughput Req. / Maximum Throughput

*: MAC Efficiency = 80% and PER = 30%, only example, other values possible

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How will 16m co-ex benefit Wi-Fi / WiMAX HO?

• WiMAX to Wi-Fi– protecting Beacon

after Wi-Fi STA is associated with Wi-Fi AP while WiMAX MS is still transmitting data

• WiFi to WiMAX– start co-ex operation

right after Basic Capability Negotiation to avoid long authentication delay

Rev2 Co-Ex starts here16m Co-Ex starts

here

Authentication may take long, and data transmission over Wi-Fi needs to be protected