IEEE 802.16j Multi-hop Relay
Presenter: Yi-Hsueh Tsai
Dec 22, 2008

1
Outline
•
•
•
•
•
•
•
•

Overview
Frame structure
RS Network entry
RS Bandwidth Request
SS Network entry
SS Bandwidth Requ...
Why Do We Need MR Networks?

• Multihop relay (MR) network to gain:
– Throughput Enhancement
– Coverage Extension.
Problem...
Concept of Relay
Aiming at developing relay based on IEEE 802.16e, to gain:
• Coverage extension
• Throughput enhancement
...
Benefits of Using Relay
Decreased Mobile Station power per bit
transmitted and received: increases MS
battery life!

RS

F...
WiMAX Relay Under-roof Usage Models
• IEEE 802.16j is the enabler
to extend the carrier
WiMAX deployment into
enterprise s...
WiMAX Network Architecture
NAP
ASN

Public IP network

R6

BS

ASP
R8

ASN-GW
(FA)

R6
BS

R3

NSP

R4

CSN

ASN
R6
Firewa...
16j System Topology
MR-BS

One Hop

MS: Mobile Station
RS: Relay Station
MR-BS: MR Base Station

Two Hop

One Hop

MS1

RS...
Terminology
802.16j

MR-BS

Relay Link

RS
Access Link

Access Link

MS

Relay Link

MS

802.16e

•
•

RS

Access Link

MS...
MR Relay Station Architecture
Processor Subsystem

BB Subsystem

Memory

RF & Antenna
Subsystem

HW Accelerator

MAC Proce...
SS/MS, 16j RS and MR-BS
SS/MS

MR-BS

RS

MS Applications
& Utilities

RS Applications
& Utilities

Management

Management...
16j MR Functional Blocks
RS

MR-BS

RS Applications/Utilities

BS Applications/Utilities

L3+

SNMP

IP Tunnel

SNMP

Inte...
STR relay frame structure
OFDMA symbol number
k+7

k+9

k+11 k+13 k+15

DL burst #3

UL burst #3 (for RS)

k+5

k+7

UL bu...
RS network entry procedure
Scan for downlink
channel

Negotiate basic
capabilities

Neighbour station
measurement
report

...
RS network entry procedure
The procedure can be divided into the following phases:
a) Scan for DL channel and establish sy...
RS network re-entry optimization
The MR-BS may instruct the RS to omit the following phases by the
RS network entry optimi...
Scanning and sync. to the DL
1. RS follows the scanning and synchronization
procedure similar to that of the SS.
2. The RS...
1st stage access station selection
1. The MR-BS and the RS may transmit the TLV
encoded parameter end-to-end Metric in the...
CDMA Ranging
1. Upon receiving a UCD message containing an
RS_Initial_Ranging_Code TLV from an MR-BS
or non-transparent RS...
CDMA Ranging
3. Upon receiving an RNG-RSP containing status
abort with preamble indexes, the ranging RS
shall scan for a D...
Handle RS Registration (at MR-BS)
Wait for REG-REQ
REG-REQ
Stop T17
No

Authorization
Policy support?
Yes

Calculate HMAC/...
Handle RS Registration (at RS)
Wait for REG-RSP
REG-RSP
Stop T6
Yes

Perform neighbor
meas. report?

No

T67 as skipping m...
RS neighbor station measurement report
1. The neighbor measurement report procedure is an
optional procedure as indicated ...
RS neighbor station measurement report
4. The RS shall then send the measurements,
including the signal strength and pream...
RS neighbor station measurement report

Perform neighbor measurement report

Wait for RS_NBR-MEAS-REP

RS_NBR-MEAS-REP

RS...
2nd stage access station selection
1. The 2nd access station selection procedure is an
optional procedure as indicated by ...
2nd stage access station selection
3. If the current access station is changed and is
located in the same MR-cell, the MR-...
2nd stage access station selection

Wait for RNG-REQ from the same RS
Wait for RS_AccessRS-REQ

RS_NBR-MEAS-REP
RS_AccessR...
2nd stage access station selection (at MR-BS)
Perform access station selection
Determine access station
Yes

Change access...
Path creation and tunnel establishment
1. This step may be performed to create a path, to
establish tunnels and to bind th...
RS operation parameters configuration
1. The MR-BS shall determine the RS's operation
parameters and send RCD and RS_Confi...
RS operation parameters configuration
4. The RS shall start transmitting its own frame start
preamble at the frame indicat...
RS operation parameters configuration
Wait for RS_Config-CMD
RS_Config-CMD

RS is operational

Stop T67

RS_Config-CMD
No
...
Management CID allocation
1. Local CID allocation mode allows an RS to
assign CIDs from this range to its subordinate
stat...
Network entry state machine
Got CDMA initial ranging code/
Handle CDMA initial ranging code
(send RNG-RSP (continue))
Got ...
RS dedicate ranging codes
1. RSs uses contention-based CDMA BR process
2. Subsets of codes shall be allocated in the UCD
C...
SS network entry Procedures

37
SS network entry Procedures
1. The RS shall monitor the Ranging Channel specified in
its UL-MAP.
2. When the RS detects a ...
SS network entry Procedures
5. If the RS is in local CID allocation mode,
–

RS shall assign and forward CIDs to the SS vi...
SS network entry Procedures
Wait for RNG-REQ containing SS MAC address with ranging CID
RNG-REQ containing SS MAC address
...
SS network entry (local CID/not local CID)

41
SS network entry (not local CID)

42
SS network entry (local CID)

43
SS Periodic Ranging Handling
1. The RS may want to initiate ranging based on the
channel measurements from data traffic or...
SS registration handling (at RS)
Wait for REG-REQ
REG-REQ
Stop T17
Authorization
Policy support ?

No

Yes

Calculate HMAC...
SS registration handling (at MR-BS)
Wait for REG-REQ
REG-REQ
Calculate HMAC/CMAC over REG-REQ
No

HMAC/CMAC Valid?
Yes

Se...
Relaying DCD/UCD procedure
• RS shall acknowledge the reception of DCD or UCD
messages over primary management connection ...
Scheduling Station
1. MR networks under centralized scheduling,
–

the scheduling station is always theMR-BS at the root
o...
Requests
1. Requests refer to the mechanism that RSs use to
indicate to the MR-BS scheduling station that
they need an UL ...
Bandwidth Request Handling
1. Each access station directly handles the BRs it
receives from subordinate stations.
2. A sch...
Bandwidth Request Handling
1. RSs shall handle all BRs locally.
2. To forward traffic upstream, an RS may request
uplink B...
Bandwidth Request Handling
4. When resources are available, the superordinate
station will allocate BW using the Basic CID...
Bandwidth Request Handling
RS

MS

MR-BS

BW REQ GMH
BW REQ GMH
UL-MAP
UL-MAP

MAC PDUs
MAC PDUs

Reducing latency in rela...
Bandwidth Grant Handling
1. The MR-BS/RS may send its subordinate nontransparent RSs uplink scheduling information
ahead o...
RS-SCH message format

55
Bandwidth Grant Handling
4. When an RS receives an RS-SCH management
message with uplink scheduling information, it
shall ...
Bandwidth Grant Handling
RS

MS

MR-BS

RS SCH Message
UL-MAP (Data Grant IE)
UL-MAP (Data Grant IE)
Data 1

Data 1
UL-MAP...
Polling
1. The polling procedure may be used between any
SS/RS and its scheduling station.
2. If an RS is regularly polled...
Polling
RS

MS

MR-BS

BW REQ code
CDMA Allocation IE

UL-MAP

BW REQ Header
BW REQ Header
UL-MAP
UL-MAP

MAC PDUs
MAC PDU...
Polling
RS

MS

MR-BS
RS SCH Message

UL-MAP (Polling)
UL-MAP (Polling)
Bandwidth Request

Bandwidth Request

UL-MAP (Poll...
Contention-based CDMA BRs
• The Contention-based BR mechanisms defined
above for the SS and the BS shall be applicable for...
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IEEE 802.16j Multi-hop Relay

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  • BLUE: Independence from wired connection allows flexible deployment
    improves service (i.e. deployer can be very specific about addressing infrastructure needs)
    Can deploy RSs to provide coverage in coverage holes, provide access remote clusters of users, to provide capacity in specific areas. RSs can also be deployed on a temporary basis, for example in disaster recovery situations of to provide coverage on a temporary basis for events.
    speeds time to market, reduces site acquisition and backhaul costs (initial AND monthly).
    RED: Replacing low rate, unreliable links with high rate, reliable links (both wireless):
    improves service by increasing data rate and reducing bit errors
    reduces bit transmit costs by aggregating more traffic at the MMR-BS (DS3 is ~30x data rate but only 3x cost of DS1) and improving trunking efficiency
    GREEN: Load sharing and the inherent multi-path redundancy
    improves service since system can adapt to variations in load and handle infrastructure failures easier
    reduces infrastructure costs since system does not have to be permanently dimensioned to handle peak loads, but can better adapt to load variations and since redundant equipment is not necessary.
    LIGHT BLUE: Spectrally efficient architectures due to low cost RS and site/backhaul costs:
    improves service by increasing access to bandwidth
    reduces antenna costs since there is less need for complex antenna structures
    Before we discuss the limitations of MMR, I wanted to discuss some of the ways in which MMR networks can be deployed. Because of the flexibility that exists in the placement of RS cell sites, MMR can be used to improve the coverage and capacity of existing WiMAX networks, by augmenting the coverage and capacity of cells in the current network. RSs can also be deployed to provide coverage within buildings or moving vehicles such as trains. Finally, they can be deployed on a temporary basis as well.
  • NMS: Network Management System
  • <number>
  • IEEE 802.16j Multi-hop Relay

    1. 1. IEEE 802.16j Multi-hop Relay Presenter: Yi-Hsueh Tsai Dec 22, 2008 1
    2. 2. Outline • • • • • • • • Overview Frame structure RS Network entry RS Bandwidth Request SS Network entry SS Bandwidth Request Relaying Broadcast Messages Q&A 2
    3. 3. Why Do We Need MR Networks? • Multihop relay (MR) network to gain: – Throughput Enhancement – Coverage Extension. Problems: 1. Shadow of buildings 2. Valley between buildings 3. Coverage extension at cell edge 1 2 3 3
    4. 4. Concept of Relay Aiming at developing relay based on IEEE 802.16e, to gain: • Coverage extension • Throughput enhancement Mobile Access RS Multihop Relay Coverage hole RS RS Penetration into inside room Shadow of buildings RS Coverage extension to isolated area RS RS BS RS RS Coverage extension at cell edge Valley between buildings RS Underground Acronym: BS: Base Station RS: Relay Station Source: 16j TG, 80216j-06_015 4
    5. 5. Benefits of Using Relay Decreased Mobile Station power per bit transmitted and received: increases MS battery life! RS Flexible cell site placement: speeds deployment, reduces site acquisition and backhaul costs! RS  RS L RS RS RS RS RS RS BS RS Spectrally efficient architectures: reduces costly antenna structures! Load sharing and multi-path redundancy: reduces infrastructure costs! But, issues to be resolved – Latency and overhead increase with each hop – Infrastructure complexity – Interference still limits performance 5 Source: Intel, 2006
    6. 6. WiMAX Relay Under-roof Usage Models • IEEE 802.16j is the enabler to extend the carrier WiMAX deployment into enterprise space RS node supports the mobility deployment Source: Nortel 6
    7. 7. WiMAX Network Architecture NAP ASN Public IP network R6 BS ASP R8 ASN-GW (FA) R6 BS R3 NSP R4 CSN ASN R6 Firewall R3 BS R8 R6 BS ASN-GW (FA) AAA-server R2 NMS LR HA RS RS NSP R1 MS R5 MS 7 ASN : access service network CSN : connectivity service network NAP : network access provider NSP : network service provider
    8. 8. 16j System Topology MR-BS One Hop MS: Mobile Station RS: Relay Station MR-BS: MR Base Station Two Hop One Hop MS1 RS1 MS2 Two Hop RS2 Three Hop MS3 • MR-BS (multihop relay base station): A generalized equipment set providing connectivity, management, and control of relay stations and subscriber stations. • RS (relay station): A generalized equipment set, dependent of a multihop relay base station (MRBS), providing connectivity, management, and control of other RSs or subscriber stations (SS). The air interface between an RS and an SS is identical to the air interface between a BS and an SS. 8
    9. 9. Terminology 802.16j MR-BS Relay Link RS Access Link Access Link MS Relay Link MS 802.16e • • RS Access Link MS access link: An 802.16 radio link that originates or terminates at an MS. The access link is either an uplink or downlink relay link (R-link): A radio link between an MR-BS and a RS or between a pair of RSs. This can be a relay uplink or downlink. Source:資策會 NMi, 2007/05 9
    10. 10. MR Relay Station Architecture Processor Subsystem BB Subsystem Memory RF & Antenna Subsystem HW Accelerator MAC Processor Relay App/Utilities Transceiver 1 Data OFDMA Baseband (With 16j Enhancements) Transceiver 2 Ctrl Transceiver n Wired I/O Control Platform & Mechanical 10
    11. 11. SS/MS, 16j RS and MR-BS SS/MS MR-BS RS MS Applications & Utilities RS Applications & Utilities Management Management IP services IP services Optional Routing Services RRM & Handover Support function RRM & Handover Support function RRM & Handover AAA/DHCP/MIP Proxy 802.16e MAC 802.16 MAC 802.16 MAC Air Link Security Air Link Security Air Link Security IP and Tunnel services 16e OFDMA PHY BS Applications OA&M OFDMA PHY OFDMA PHY (w/ 16j enhancements) (w/ 16j enhancements) BS Radio Access Plane 11 Wired MAC/PHY BS Backbone Plane
    12. 12. 16j MR Functional Blocks RS MR-BS RS Applications/Utilities BS Applications/Utilities L3+ SNMP IP Tunnel SNMP Internet Protocol Internet Protocol RS Init Path Sel./Maint. Mobility Support Scheduling Mobility ARQ Power Control Support BW Req. (Allocation) ARQ Power Control PDU/Burst Processing PDU/Burst Processing BW Grant L2 Security Ranging L2 Security Ranging Spatial Diversity L1 RS Entry & Control Scheduling L2 Meas. & Rep. Power Control Spatial Diversity Power Control HARQ Frame Structure HARQ Frame Structure OFDMA Synchronization OFDMA (16j Enhancement) Synchronization (16j Enhancement) : new modules in MMR-BS : depends on the RS capabilities 12
    13. 13. STR relay frame structure OFDMA symbol number k+7 k+9 k+11 k+13 k+15 DL burst #3 UL burst #3 (for RS) k+5 k+7 UL burst #4 DL burst #6 (for RS) k+9 UL burst #5 (for RS) TTG DL Subframe Frame j k+11 k+13 k+15 UL Subframe RTG Frame j+1 k+17 k+20 k+23 k+26 k k+1 FCH DL burst #1 k+7 k+9 k+11 k+13 k+15 RTG Frame j+1 k+17 k+20 k+23 k+26 DL burst #3 (for RS) k k+1 FCH k+5 UL Subframe Ranging subchannel UL burst #1 DL burst #4 UL burst #2 UL burst #3 DL burst #5 DL burst #2 DL-MAP k+3 FCH DL-MAP Preamble Subchannel Logical number k+1 (carrying the UL-MAP) k s s+1 s+2 s+3 TTG Frame j DL-MAP Transmitter mode for communicating with MR-BS s+L DL Subframe Preamble Receiver mode for communicating with MR-BS Preamble Subchannel Logical number RS Frame (Carrier f1) s s+1 s+2 s+3 (Carrier f2) DL-MAP UL burst #2 DL burst #5 k+3 k+1 UL burst #1 s+L k+1 k Ranging subchannel DL burst #4 (for RS) DL burst #2 k k+17 k+20 k+23 k+26 FCH k+5 Preamble DL burst #1 FCH k+3 DL-MAP Preamble Subchannel Logical number MR-BS Frame Carrier f1 s s+1 s+2 s+3 k+1 (carrying the UL-MAP) k UL burst #4 (for RS) DL burst #6 UL burst #5 s+L DL Subframe TTG Frame j UL Subframe • The MR-BS frame structure is the same as the frame structure defined in 8.4.4.2. • The RS frame structure is the same as the frame structure defined in 8.4.4.2 on the 2nd carrier of the RS. • The RS shall receive data in the DL subframe and transmit data in the UL subframe on the 1st carrier as a SS. RTG Frame j+1 13
    14. 14. RS network entry procedure Scan for downlink channel Negotiate basic capabilities Neighbour station measurement report Establish IP connectivity Downlink synchronization established Basic capabilities negotiated Neighbour station measurement reported Establish time of day Obtain uplink parameters RS authorization and key exchange Second Stage Access Station Selection Transfer operational parameters Uplink parameters acquired Authorization complete Second Stage Access Station Selection complete RS operation parameters configuration Ranging and automatic adjustmnets Register with MR-BS Path creation and tunnel establishment Configuration complete Ranging and automatic adjustmnets complete Registration complete Operational 14
    15. 15. RS network entry procedure The procedure can be divided into the following phases: a) Scan for DL channel and establish synchronization with the BS b) Perform 1st stage access station selection c) Obtain Tx parameters (from UCD message) d) Perform ranging e) Negotiate basic capabilities f) Authorize RS and perform key exchange g) Perform registration h) Obtaining neighbor station measurement report i) Perform 2nd stage access station selection j) Path creation and tunnel establishment k) Establish IP connectivity l) Establish time of day m) Transfer operational parameters n) Configure operation parameters 15
    16. 16. RS network re-entry optimization The MR-BS may instruct the RS to omit the following phases by the RS network entry optimization TLV 1. Negotiate basic capabilities 2. Authorize RS and perform key exchange 3. Perform registration 4. Obtaining R-link Parameters 5. Obtaining neighbor station measurement report 6. Perform access station selection 7. Path creation and tunnel establishment 8. Establish IP connectivity 9. Establish time of day 10. Transfer operational parameters 11. Configure operation parameters 16
    17. 17. Scanning and sync. to the DL 1. RS follows the scanning and synchronization procedure similar to that of the SS. 2. The RS may store preamble index and signal strength in order to report the stored values to the serving MR-BS after registration 17
    18. 18. 1st stage access station selection 1. The MR-BS and the RS may transmit the TLV encoded parameter end-to-end Metric in the DCD message to support access station selection in the MR network. 2. The RS attempting network entry may obtain the DCD TLV encodings sent by neighboring RSs and MR-BSs to select a desired access station to enter the MR network through it. 18
    19. 19. CDMA Ranging 1. Upon receiving a UCD message containing an RS_Initial_Ranging_Code TLV from an MR-BS or non-transparent RS, the ranging RS shall use the "RS Initial Ranging" code instead of the "Initial Ranging" code. 2. After receiving an RS Initial Ranging code, the MR-BS or non-ransparent RS may send an RNGRSP (abort) with preamble indexes of candidate neighbor access stations. 19
    20. 20. CDMA Ranging 3. Upon receiving an RNG-RSP containing status abort with preamble indexes, the ranging RS shall scan for a DL channel of candidate neighbor access stations and perform initial ranging. 5. The MR-BS may assign a dedicated RS CDMA periodic ranging code to the RS. 6. The process stops once the access station receives the code and forwards an RNG-RSP to the RS. 20
    21. 21. Handle RS Registration (at MR-BS) Wait for REG-REQ REG-REQ Stop T17 No Authorization Policy support? Yes Calculate HMAC/CMAC over REG-REQ Yes No HMAC/CMAC Valid? Yes Set RS capabilities supported in REG-RSP REG-RSP with Response = 1 (Message Auth. Failure) REG-RSP with Response =0 (OK) Wait for REG-REQ Yes Perform neighbor meas. report? No Start T64 Wait for RS_NBR-MEAS-REP Perform operation parameter configuration 21
    22. 22. Handle RS Registration (at RS) Wait for REG-RSP REG-RSP Stop T6 Yes Perform neighbor meas. report? No T67 as skipping measurement report Perform neighbor measurement report Wait for RS_Config-CMD 22
    23. 23. RS neighbor station measurement report 1. The neighbor measurement report procedure is an optional procedure as indicated by the RS network entry optimization TLV in the RNG-RSP message. 2. If the measurement is not required, the RS shall directly go to the RS configuration phase skipping neighbor station measurement report phase and 2nd stage access selection phases. 3. The RS obtains the neighbor monitoring scheme parameters from the RS_Config-CMD message. 23
    24. 24. RS neighbor station measurement report 4. The RS shall then send the measurements, including the signal strength and preamble index of neighbor non-transparent stations with unique BSIDs, to the MR-BS using the RS_NBRMEAS-REP message, and start a T67 timer. 5. This measurement report is used by the MR-BS to select a new access station and assign the RS a preamble index based on the report from the RS (or to continue with the current access station). 24
    25. 25. RS neighbor station measurement report Perform neighbor measurement report Wait for RS_NBR-MEAS-REP RS_NBR-MEAS-REP RS_NBR-MEAS-REP Start T67 as performing measurement report Stop T64 Wait for RS_AccessRS-REQ Perform access station selection at RS at MR-BS 25
    26. 26. 2nd stage access station selection 1. The 2nd access station selection procedure is an optional procedure as indicated by the RS network entry optimization TLV in the RNG-RSP message. 2. During this operation, the MR-BS shall determine the best path (i.e. access station) for this RS based on the RS’s neighbor station measurements and other information such as path loading. 26
    27. 27. 2nd stage access station selection 3. If the current access station is changed and is located in the same MR-cell, the MR-BS shall start T65 timer and send the RS_AccessRS-REQ message to the RS. 4. The RS shall respond with the MR_GenericACK message. 5. The MR-BS and the RS shall perform network re-entry. 6. Once T65 expires, the MR-BS shall release resources allocated to the corresponding RS. 27
    28. 28. 2nd stage access station selection Wait for RNG-REQ from the same RS Wait for RS_AccessRS-REQ RS_NBR-MEAS-REP RS_AccessRS-REQ Stop T70 Stop T67 as performing measurement report MR_Generic-ACK RS_AccessRS-REQ Network re-entry via the selected access station Start T70 Wait for RNG-REQ from the same RS at RS at MR-BS 28
    29. 29. 2nd stage access station selection (at MR-BS) Perform access station selection Determine access station Yes Change access station? RS_AccessRS-REQ No Perform operation parameter configuration Start T73 Wait for MR_Generic-ACK MR_Generic-ACK Stop T73 Start T70 Wait for RNG-REQ from the same RS 29
    30. 30. Path creation and tunnel establishment 1. This step may be performed to create a path, to establish tunnels and to bind the tunnels to this path after a RS completes the procedure of access RS selection. The tunnels, if established, could only be management tunnel and transport tunnel for the single tunnel case. 2. These tunnels are established using DSAREQ/RSP management message. The path creation and binding of tunnel CIDs to the established path shall be performed 30
    31. 31. RS operation parameters configuration 1. The MR-BS shall determine the RS's operation parameters and send RCD and RS_Config-CMD messages to configure these parameters at the RS and start a T68 timer. 2. The RS shall respond by sending an MR_Generic-ACK message to the MR-BS and stop the T67 timer 3. Then, the MR-BS and the RS shall complete the RS network entry process, enter the operational state, and stop the T68 timer. 31
    32. 32. RS operation parameters configuration 4. The RS shall start transmitting its own frame start preamble at the frame indicated by the Frame Number Action in the RS_Config-CMD message. 5. RS may maintain its synchronization by listening to the frame start preamble of its superordinate station. 6. RS shall receive the R-MAP message, if present, from the access station in the access zone. 32
    33. 33. RS operation parameters configuration Wait for RS_Config-CMD RS_Config-CMD RS is operational Stop T67 RS_Config-CMD No Non-transparent TTR mode? MR_Generic-ACK Yes Stop Lost DL-MAP Wait for Action Frame Number Stop Lost UL-MAP interval Action Frame Number Stop T1 RS is operational Stop T12 MR_Generic-ACK RS is operational 33
    34. 34. Management CID allocation 1. Local CID allocation mode allows an RS to assign CIDs from this range to its subordinate stations by the CID allocation TLV in the RS_Config-CMD. 2. RS shall assign the management CIDs that are assigned by the MR-BS to its subordinate stations (MS or RS) in the RNG-RSP during the initial ranging process. 34
    35. 35. Network entry state machine Got CDMA initial ranging code/ Handle CDMA initial ranging code (send RNG-RSP (continue)) Got CDMA initial ranging code/ Handle CDMA initial ranging code (send RNG-RSP (success) or CDMA Allocation IE) Wait for CDMA initial ranging code Wait for RNG-REQ Scan downlink channel Got CDMA Initial ranging code CDMA Initial ranging code (send RNG-RSP(abort)) Establish DL sync/ Got UL parameters Got ranging opportunity/ Send CDMA code Wait for SBC-REQ (T9 expires) Send RNG-RSP(Abort) or Got RNG-REQ/Handle RNG-REQ retransmission (send RNG-RSP(Abort) (Auth. Supported) Got SBC-REQ/Handle SBC-REQ (Auth. not supported) Got SBC-REQ/ Got SBC-REQ/ Handle SBC-REQ Handle SBC-REQ retransmission retransmission SS Authentication And Key exchange Got CMDA Allocation IE/ Send RNG-REQ with ranging CID (for normal network entry) or Send RNG-REQ with RS basic CID (for 2nd access station selection) (T17 expires or auth. failure) Send RNG-RSP(Abort) Authenticated from PKM (Auth. not supported) Got SBC-REQ/ Handle SBC-REQ retransmission Wait for REG-REQ (T17 expires) Send RNG-RSP(Abort) or RES-CMD T18 expired and have more retries/ Send SBC-REQ Wait for RS_NBRMEAS-REP (T64 expires) Send RNG-RSP(Abort) or RES-CMD Auth. not supported END Got SBC-RSP/Handle SBC-RSP Wait for ACK (T68 expires) Send RNG-RSP(Abort) T6 expired and have more retries/ Send REG-REQ Wait for Action Frame Number T67 expired and have more retries/ Send RS_NBR-MEAS-REP (T70 expires) Send RNG-RSP(Abort) Wait for SBC-RSP Wait for REG-RSP Wait for RS_AccessRSREQ or RS_ConfigCMD Got RS_Config-CMD/ Handle RS_Config-CMD retransmission (Send MR_Generic-ACK) Wait for ACK Wait for Action Frame Number Action Frame Number Got ACK Got RS_NBR-MEAS-REP/ Handle retransmission (Send RS_AccessRS-REQ) (T18 expired and retries exhausted) or (received RNG-RSP(abort) from BS) SS Authentication (T17 expires and retries exhausted) or And Key (received RNG-RSP(abort) from BS) exchange Got RS_Config-CMD/ Handle RS_Config-CMD (T73 expires) Send RNG-RSP(Abort) Got RS_NBR-MEAS-REP/ Retransmit RS_AccessRS-REQ Wait for RNG-RSP with MAC address (T6 expires and retries exhausted) or ( RNG-RSP(abort) or RES-CMD from Got REG-RSP/Handle REG-RSP Action Frame Number RS operational T3 expired and have more retries Authenticated from PKM/ Send REG-REQ, Start T6 Got ACK (Accesss station changed) Got RS_NBR-MEAS-REP/ Send RS_AccessRS-REQ Received RNG-RSP (continue) or T3 expired Auth. supported Got SBC-RSP/Handle SBC-RSP (Accesss station unchanged) Got RS_NBR-MEAS-REP/ Send RS_Config-CMD Got RS_NBR-MEAS-REP/ Retransmit RS_Config-CMD Wait for RNG-RSP or CDMA Allocation IE Got RNG-RSP (abort) with Preamble Index/ Scan another access station Got RNG-RSP with MAC address/ Handle RNG-RSP (Send SBC-REQ) End (Perform RS neighbor measurement report ) Got REG-REQ/Handle REG-REQ (Perform RS neighbor measurement report Got REG-REQ/ Handle REG-REQ retransmission Wait for ranging opportunity (T3 expired and retries exhausted) or (received RNG-RSP(abort)) ‘SS Ranging Response Processing Time’ passed Got RNG-REQ/Handle RNG-REQ (send RNG-RSP(success)) Got RNG-REQ/ Handle RNG-REQ retransmission (send RNG-RSP(success)) (T3 expired and retries exhausted) or (received RNG-RSP(abort)) Wait for RNG-REQ from the same RS RS operational 35 Got RS_AccessRS-REQ/ Handle RS_AccessRS-REQ End
    36. 36. RS dedicate ranging codes 1. RSs uses contention-based CDMA BR process 2. Subsets of codes shall be allocated in the UCD Channel Encoding for – – – – – – Initial Ranging Periodic Ranging Handover Ranging Bandwidth Requests RS Initial Ranging RS Dedicated Codes 36
    37. 37. SS network entry Procedures 37
    38. 38. SS network entry Procedures 1. The RS shall monitor the Ranging Channel specified in its UL-MAP. 2. When the RS detects a ranging code on its access link, it shall perform adjustments directly with the SS with no interaction with the MR-BS. 3. When the RS receives a ranging code successfully, it shall provide bandwidth on the access link on which the SS can send an RNG-REQ containing its MAC address by inserting a CDMA_Allocation_IE in the UL-MAP. 4. When the RS receives an RNG-REQ with an SS MAC address with ranging CID, it shall either assign CIDs to the SS or request them from the MR-BS. 38
    39. 39. SS network entry Procedures 5. If the RS is in local CID allocation mode, – RS shall assign and forward CIDs to the SS via an RNG-RSP. 6. If the RS is not in local CID allocation mode, – – – It shall forward the RNG-REQ containing the SS MAC address to the MR-BS on its RS basic CID after removing the TLVs it manages and start the T66 timer. If the SS is accepted, the MR-BS shall assign CIDs and send them in a RNG-RSP to the RS on the RS basic CID. If the T66 timer expires before the RNG-RSP is received, the RS shall stop the procedure. Otherwise, the access RS shall fill in the TLVs it manages and forward the RNG-RSP to the SS on the ranging CID. 39
    40. 40. SS network entry Procedures Wait for RNG-REQ containing SS MAC address with ranging CID RNG-REQ containing SS MAC address Start T66 RNG-REQ with RS basic CID to MR-BS Wait for RNG-RSP containing matching MAC address with ranging CID Timeout T66 RNG-RSP with matching MAC address End Stop T66 RNG-RSP with ranging CID to SS End 40
    41. 41. SS network entry (local CID/not local CID) 41
    42. 42. SS network entry (not local CID) 42
    43. 43. SS network entry (local CID) 43
    44. 44. SS Periodic Ranging Handling 1. The RS may want to initiate ranging based on the channel measurements from data traffic or a CDMA-based BR ranging code received from the SS. 2. To initiate the periodic ranging process, the RS shall send an unsolicited RNG-RSP directly to the SS without interaction with the MR-BS. 44
    45. 45. SS registration handling (at RS) Wait for REG-REQ REG-REQ Stop T17 Authorization Policy support ? No Yes Calculate HMAC/CMAC over REG-REQ No HMAC/CMAC Valid? Yes REG-REQ to MR-BS REG-RSP with Response = 1 (Message Auth. Failure) to SS Start T6 Wait for REG-REQ Wait for REG-RSP with matching primary CID REG-RSP with matching primary CID Stop T6 Calculate HMAC/CMAC over REG-RSP No HMAC/CMAC Valid? RS Auth. Failure Yes REG-RSP to SS 45
    46. 46. SS registration handling (at MR-BS) Wait for REG-REQ REG-REQ Calculate HMAC/CMAC over REG-REQ No HMAC/CMAC Valid? Yes Set SS capabilities supported in REG-RSP End REG-RSP with Response =0 (OK) to RS No Managed SS? Establish provisioned connections 3 Yes Start T13 Wait for TFTP-CPLT 46
    47. 47. Relaying DCD/UCD procedure • RS shall acknowledge the reception of DCD or UCD messages over primary management connection by sending an acknowledgment header • Transaction ID of the ACK header shall be set to the Configuration Change Count of DCD or UCD message. Access RS Serving MR-BS send map with broadcast CID Send DCD or UCD with RS primary CID. MS R-MAP DCD or UCD Acknowledgment header [Receive DCD or UCD] Send Acknowledgment header containing DCD or UCD message type and Transaction ID as the 8-bit LSB DCD or UCD count 47
    48. 48. Scheduling Station 1. MR networks under centralized scheduling, – the scheduling station is always theMR-BS at the root of the PMP tree 2. MR networks under distributed scheduling – the scheduling station of a given SS/RS is the first station along the route to the MR-BS that transmits MAPs 48
    49. 49. Requests 1. Requests refer to the mechanism that RSs use to indicate to the MR-BS scheduling station that they need an UL bandwidth allocation. 2. A request may come as a stand-alone BR header or it may come as a Piggyback Request. The capability of Piggyback Request is optional. 49
    50. 50. Bandwidth Request Handling 1. Each access station directly handles the BRs it receives from subordinate stations. 2. A scheduling RS may receive BRs from its subordinate stations via the MAC signaling header, the grant management subheader or the CDMA BR code. 50
    51. 51. Bandwidth Request Handling 1. RSs shall handle all BRs locally. 2. To forward traffic upstream, an RS may request uplink BW via a stand-alone BR header or piggyback the request on the relay MAC PDUs. 3. An RS may combine the BRs that arrive from subordinate stations together with the BW needs of queued packets into one BR header per QoS class. 51
    52. 52. Bandwidth Request Handling 4. When resources are available, the superordinate station will allocate BW using the Basic CID. 5. The RS should transmit a BR header soon after it receives a BR header from one of its subordinate stations instead of waiting for the actual packets to arrive in order to reduce delay in relaying traffic. 52
    53. 53. Bandwidth Request Handling RS MS MR-BS BW REQ GMH BW REQ GMH UL-MAP UL-MAP MAC PDUs MAC PDUs Reducing latency in relaying traffic by transmitting BR header on R-UL before packets arrive 53
    54. 54. Bandwidth Grant Handling 1. The MR-BS/RS may send its subordinate nontransparent RSs uplink scheduling information ahead of time via an RS-SCH management message, which indicates when a given uplink BW allocation will be granted to the subordinate RS, the size of the allocation, and which CID it is intended for. 2. The actual BW grant is issued to the subordinate RS using a Data Grant IE in an upcoming UL-MAP. 3. In the case of periodic BW grants, the scheduling information need only be sent once 54
    55. 55. RS-SCH message format 55
    56. 56. Bandwidth Grant Handling 4. When an RS receives an RS-SCH management message with uplink scheduling information, it shall look up the "next hop" of the given CID. Based on this scheduling information and the "next hop" of the CID, the RS can determine the appropriate BW allocations and associated RS UL allocation frame offset on the uplinks it controls. 5. The RS sends its own RS-SCH management messages to its subordinate RSs to inform them of the BW allocation decisions it makes. 56
    57. 57. Bandwidth Grant Handling RS MS MR-BS RS SCH Message UL-MAP (Data Grant IE) UL-MAP (Data Grant IE) Data 1 Data 1 UL-MAP (Data Grant IE) UL-MAP (Data Grant IE) Data 1 Data 1 57
    58. 58. Polling 1. The polling procedure may be used between any SS/RS and its scheduling station. 2. If an RS is regularly polled, it can transmit a BR header on the relay UL to its superordinate station as soon as it detects impending UL traffic in order to reduce delay. 3. An scheduling station may inform a subordinate RS of upcoming polling via an RS-SCH management message 58
    59. 59. Polling RS MS MR-BS BW REQ code CDMA Allocation IE UL-MAP BW REQ Header BW REQ Header UL-MAP UL-MAP MAC PDUs MAC PDUs 59
    60. 60. Polling RS MS MR-BS RS SCH Message UL-MAP (Polling) UL-MAP (Polling) Bandwidth Request Bandwidth Request UL-MAP (Polling) UL-MAP (Polling) Bandwidth Request Bandwidth Request 60
    61. 61. Contention-based CDMA BRs • The Contention-based BR mechanisms defined above for the SS and the BS shall be applicable for the scheduling RS and the MR-BS respectively. 61

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