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Relay Operation in IEEE 802.11ad. Date: 2010-05-01. Proposal overview. This presentation is part and is in support of the complete proposal described in 802.11-10/432r0 (slides) and 802.11-10/433r0 (text) that: Supports data transmission rates up to 7 Gbps
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Relay Operation in IEEE 802.11ad Date: 2010-05-01 Carlos Cordeiro, Intel, et. al.
Proposal overview • This presentation is part and is in support of the complete proposal described in 802.11-10/432r0 (slides) and 802.11-10/433r0 (text) that: • Supports data transmission rates up to 7 Gbps • Supplements and extends the 802.11 MAC and is backward compatible with the IEEE 802.11 standard • Enables both the low power and the high performance devices, guaranteeing interoperability and communication at gigabit rates • Supports beamforming, enabling robust communication at distances beyond 10 meters • Supports GCMP security and advanced power management • Supports coexistence with other 60GHz systems • Supports fast session transfer among 2.4GHz, 5GHz and 60GHz Carlos Cordeiro, Intel, et. al.
Outline • Introduction • mmWave Relay Operation • Common Relay Setup • Link Switching Type • Link Cooperating Type • Relay Operation-type Change • Conclusion • Appendix Kapseok Chang, ETRI
Introduction (1/3) • Problem statement for 60 GHz channel • P1: High directivity and High path loss • Large free space path loss (22 dB higher than 5GHz [1]) • Resulting in shortening communication coverage (or range) • P2: High penetration loss by human or wall • 60GHz ray cannot penetrate most walls and doors. • High penetration loss (e.g., human body ~18 to 36 dB [2]) • Resulting in no or lower-rate communication between source and destination STAs Kapseok Chang, ETRI
Introduction (2/3) • Current solution of P1 • Beam-forming (BF) • Previous 60 GHz standards have sought for coverage up to 10 meters in some NLOS PHY channel conditions. • It is insufficient to further extend coverage with maintaining required throughput in indoor 60 GHz wireless environments [3]. • Current solution of P2 • Beam-steering • A bad link detection and then scheduling of next best beam direction • It is insufficient in case of no reflector nearby or insufficient one [3]. • Fast session transfer (60 GHz 2.4/5 GHz) in current TGad functional requirements • Coverage extension, but throughput reduction Kapseok Chang, ETRI
Introduction (3/3) • In order to complement current solutions of P1 and/or P2, we support relay operation with the aid of relay-supportable STA as follows, • Relay operation • Link switching type • Link cooperating type • Relay Operation-type Change • According to link channel quality, type change can be made. Kapseok Chang, ETRI
mmWave Relay Operation (1/3) • Relaying allows a source relay usable mSTA (RUS) to transmit frames to a destination relay usable mSTA (RUS) with the assistance of another mSTA called the relay supportable mSTA (RSUS). • A source RUS, a destination RUS and an RUS establish two types of relay operation • Link switching • Link cooperating, and Relay Operation-type Change RSUS (‘R’) Relay link S-R Relay link (R-D) Source RUS (‘S’) Destination RUS (‘D’) Direct link (S-D) Kapseok Chang, ETRI
mmWave Relay Operation (2/3) • Link Switching type • If the S-D direct PHY link is disrupted, the source RUS redirects the transmission of frames addressed to the destination RUS via the RSUS. • Direct link between the source RUS and destination RUS can resume after the direct link between them is recovered. • For realization of the link switching, it is needed as follows, • Common Relay setup procedures including BF procedure via relay • Frame exchange and link feedback rule RSUS S-R Relay link R-D Relay link Destination RUS Source RUS S-D Direct link Kapseok Chang, ETRI
mmWave Relay Operation (3/3) STA Cooperation • Link Cooperating type • The RSUS is actively involved in the direct link communication between S-D. At the same time, a frame transmission from the source RUS to the destination RUS is repeated by the RSUS. • It can possibly increase the signal quality received at the destination RUS. • For realization of the Link cooperating, it is needed as follows, • Additional Relay setup procedure (i.e., Transmission time-Point Adjustment (TPA)) for Receive multi-synchronization at the destination RUS • Frame exchange and link feedback rule RSUS S-R Relay link R-D Relay link Source RUS Destination RUS S-D Direct link Kapseok Chang, ETRI
Common Relay Setup Kapseok Chang, ETRI
Contents • Objective • Common Relay Link Setup • Relay capabilities and RSUS discovery procedures • RSUS selection procedure • RLS (Relay link Setup) procedure Kapseok Chang, ETRI
Objective • We describe the procedures that a source RUS, a destination RUS and an RSUS employ to setup a relay operation among these STAs. • These procedures are commonly used for both • Link Switching type • Link Cooperating type • In the order we perform the following procedures: • Relay capabilities and RSUS discovery procedures • RSUS selection procedure • RLS procedure Kapseok Chang, ETRI
Relay Link Setup (1/11) • Simple scenario considered for explanation • There exist a PCP/AP, a source RUS, RSUS, and destination RUS. • The number of RSUSs can be multiple within a BSS. • The considered scenario is shown in below Kapseok Chang, ETRI
Relay Link Setup (2/11) • Relay capabilities and RSUS discovery procedures • The source STA that intends to setup relay operation with a destination STA shall obtain the relay capabilities of the destination STA prior to initiating the relay setup procedure with the destination STA. • The source STA shall only attempt to setup relay operation with the destination STA if both STAs are RUS, and there exists at least one RSUS in the BSS. • Relay Capabilities Information Element Kapseok Chang, ETRI
Relay Link Setup (3/11) • Relay capabilities and RSUS discovery procedures (cont’d) • Relay Capabilities Information Element (IE) (cont’d) • This IE is embedded in the Beacon, Association Request/Response, Information Request/Response. • The sub-filed definition in the Relay Capabilities Info field • Relay Supportability • Indicates that STA is capable of relaying via itself by transmitting and receiving frames between a pair of other STAs. A STA supporting relay is named “relay STA”. • Set to 1 if STA is relay supportable. OW set to 0. Kapseok Chang, ETRI
Relay Link Setup (4/11) • Relay capabilities and RSUS discovery procedures (cont’d) • Relay Capabilities Information Element (IE) (cont’d) • The sub-filed definition in the Relay Capabilities Info field (cont’d) • Relay Usability • Indicates that STA is capable of using frame-relaying through a relay STA. • Set to 1 if STA is relay usable. OW set to 0. • Relay Permission • Indicates whether the PCP/AP allows relay operation to be used within his BSS. • Set to 1 if relay operation is allowed. OW set to 0. Kapseok Chang, ETRI
Relay Link Setup (5/11) • Relay capabilities and RSUS discovery procedures (cont’d) • Relay Capabilities Information Element (IE) (cont’d) • The sub-filed definition in the Relay Capabilities Info field (cont’d) • A/C Power • Indicates that relay STA is capable of obtaining A/C power. • Set to 1 if relay STA is being supplied by A/C power. OW set to 0. • Mobility • Indicates that relay STA is capable of support mobility. • Set to 1 if relay STA is capable of supporting mobility. OW set to 0. Kapseok Chang, ETRI
Relay Link Setup (6/11) • Relay capabilities and RSUS discovery procedures (cont’d) • Relay Capabilities Information Element (IE) (cont’d) • The sub-filed definition in the Relay Capabilities Info field (cont’d) • Relay Preference • Indicates that a STA prefers to become RSUS rather than RUS. • Set to 1 if a STA prefers to be RSUS. OW set to 0. • Duplex • Indicates whether relay STA is capable of full duplex and amplify-and-forward (FD/AF) or half duplex and decode-and-forward (HD/DF). • Set to 01 (only FD/AF). Set to 10 (only HD/AF). • Set to 11 (both FD/AF and HD/AF). The value 00 is reserved. Kapseok Chang, ETRI
Relay Link Setup (7/11) • Relay capabilities and RSUS discovery procedures (cont’d) • Relay Capabilities Information Element (IE) (cont’d) • The sub-filed definition in the Relay Capabilities Info field (cont’d) • Cooperation • Indicates whether a STA is capable of supporting Link Cooperating type. • Set to 1 if a STA supports both Link Cooperating and Link Switching types. • Set to 0 if a STA supports only Link Switching or if the Duplex field is set to 01. Kapseok Chang, ETRI
Relay Link Setup (8/11) • Relay capabilities and RSUS discovery procedures (cont’d) Kapseok Chang, ETRI
Relay Link Setup (9/11) • RSUS selection procedure Kapseok Chang, ETRI
Relay Link Setup (10/11) • RSUS selection procedure (cont’d) • The selection of the RSUS is implementation-dependent, and it can be based on information contained within an RSUS’s Relay capability and channel quality. Kapseok Chang, ETRI
Relay Link Setup (11/11) • Relay Link Setup (RLS) procedure Kapseok Chang, ETRI
Link Switching Type Kapseok Chang, ETRI
Contents • SP Request and Allocation • Frame Exchange Rules for FD/AF Relay • Frame Exchange Rules for HD/DF Relay Kapseok Chang, ETRI
SP Request and Allocation • By using an ADDTS Request frame for which the source AID and the destination AID fields within the Extended mmWave TSPEC element are equal to, respectively, the source RUS and the destination RUS pair, the source RUS requests an SP to the PCP/AP • The PCP/AP schedules an SP with the source STA as the source RUS and the destination STA as the destination RUS. • The selected RSUS shall check the value of the source AID and the destination AID fields of each SP allocation within an Extended Schedule element it receives in a mmWave Beacon or Announce frame from the PCP/AP. • If the value of the source AID and the destination AID fields of an SP allocation correspond to the source RUS and the destination RUS, the RSUS is allowed to operate as an RSUS during that SP allocation. Kapseok Chang, ETRI
Frame Exchange Rules for FD/AF Relay (1/4) • Link Change Interval • Indicates an opportunity to change the link used for communication. • Data Sensing Time • Indicates the defer time offset from the start of the next Link Change Interval when current link is unavailable, for implicit signaling for link switching. Kapseok Chang, ETRI
Frame Exchange Rules for FD/AF Relay (2/4) • A source RUS shall use the direct link to initiate frame transmission to the destination RUS at the start of the first SP allocated between the source RUS and destination RUS. Kapseok Chang, ETRI
Frame Exchange Rules for FD/AF Relay (3/4) • If a source RUS transmits a frame to the destination RUS via the direct link but does not receive an expected ACK frame or BA frame from the destination RUS during a Link Change Interval period, • the source RUS shall start its frame transmission after Data Sensing Time from the start of the following Link Change Interval period and use the RSUS to forward frames to the destination RUS. Kapseok Chang, ETRI
Frame Exchange Rules for FD/AF Relay (4/4) • The destination does not receive a valid frame from the source within Data Sensing Time after the start of a Link Change Interval, the destination shall immediately change the link to attempt to receive frames from the source through the RSUS, which is a sort of implicit signaling for link switching. Kapseok Chang, ETRI
Frame Exchange Rules for HD/DF Relay (1/4) • A source RUS shall use the direct link to initiate frame transmission to the destination RUS at the start of the first SP allocated between the source RUS and destination RUS. • If the direct link is used in communication, Link Change Interval is employed. • If the relay link is used in communication, 1st and 2nd Periods are employed. Kapseok Chang, ETRI
Frame Exchange Rules for HD/DF Relay (2/4) • If a source RUS transmits a frame to the destination RUS via the direct link but does not receive an expected ACK frame or BA frame from the destination RUS during a Link Change Interval period, • the source RUS should change the link used for frame transmission at the start of the following First Period and transmit frames to the RSUS. Kapseok Chang, ETRI
Frame Exchange Rules for HD/DF Relay (3/4) • In the First Period, • the source RUS shall transmit a frame to the RSUS. In this case, the destination RUS can implicitly indicate that the link switching happens. And then the RSUS responds within SIFS. • In the Second Period, • the RSUS shall forward the frame received from the source RUS to the destination RUS . • Then the destination RUS responds within SIFS. Kapseok Chang, ETRI
Frame Exchange Rules for HD/DF Relay (4/4) • The source RUS may transmit a Relay ACK Request frame to the RSUS to determine whether all frames forwarded through the RSUS were successfully received by the destination RUS. • Upon reception of a Relay ACK Request frame, the RSUS shall respond with a Relay ACK Response frame and set the BlockAck Bitmap field to indicate which frames have been successfully received by the destination RUS. Kapseok Chang, ETRI
Link Cooperating Type Kapseok Chang, ETRI
Contents • TPA (Transmission time-Point Adjustment) Procedure • SP Request and Allocation • Data Transmission Rules Kapseok Chang, ETRI
TPA (Transmission time-Point Adjustment) Procedure (1/5) • A source RUS, a destination RUS, and an RSUS that wish to setup a link cooperating relay shall additionally perform the TPA procedure, to establish a link cooperating relay. • Motivation on this procedure • For Link Cooperating, the received signal from the source RUS and that from the RSUS should be multi-synchronized at the destination RUS in order to avoid the ICI (OFDM transmission mode) or the ISI (SC transmission mode). • For example, if the distance difference between S-D and R-D links is higher than about 7.5m, the arrival time deviation between them exceeds the cyclic prefix duration, which leads to ICI. Even if the time deviation is within CP, ICI may occurs owing to the delay spread from S. Kapseok Chang, ETRI
TPA Procedure (2/5) • For estimating the arrival timing offsets from S and R • D sends R and S their TPA Request frames sequentially. • Request the Transmission time-Point Adjustment for R and S. • Include the pre-defined time (Dtime) when for R and S to transmit their TPA Response frame to D for TPA estimation at D. • Just after Dtime plus each propagation delay, R and S send their TPA Response frames to D, respectively. Kapseok Chang, ETRI
TPA Procedure (3/5) • For estimating the arrival timing offsets from S and R (cont’d) • Then, D estimates the time deviations (i.e., 2*dTDR, 2*dTDS) between Dtime and each arrival time from R and S. • For estimating the propagation delay from S to R • It is necessary that S should know the starting-time when R transmits data to D. Kapseok Chang, ETRI
TPA Procedure (4/5) • For estimating the propagation delay from S to R (cont’d) • S sends R its TPA Request frame. • Include the pre-defined time (Dtime) when for R to transmit its TPA Response frame to S for propagation delay (dTSR) estimation. • Just after Dtime plus dTSR, R sends its TPA Response frame to S. • Then, S estimates the time deviation (i.e., 2*dTSR) between Dtime and the arrival time from R. Kapseok Chang, ETRI
TPA Procedure (5/5) • For giving R its transmission time-point adjustment information • After the time when R transmits the TPA Response frame to S, D sends R its TPA Request frame that • Includes the pre-defined time (Dtime) when for R to transmit its TPA Response frame to D. • The timing offset adjustment value (i.e., dTDS-dTDR) that enables R to transmit its TPA response frame after (dTDS-dTDR) time duration from Dtime. • Then, R transmits its TPA Response frame to D for confirmation. Kapseok Chang, ETRI
SP Request and Allocation • If the source RUS receives a TPA Report frame that indicates the successful completion of the TPA procedure with the RSUS and the destination RUS, • the source RUS uses the procedure in 11.4 to request an SP allocation with the destination RUS. • The source RUS can use the SP allocation for communication with the destination RUS with the assistance of the RSUS. Kapseok Chang, ETRI
Data Transmission Rules (1/4) • In the allocated SP, T1 and T2 for a cooperated data frame transfer are determined by the packet transmission time at each transmission from the source RUS to the destination RUS within the SP. Kapseok Chang, ETRI
Data Transmission Rules (2/4) • At the start of each time T1, the source RUS transmits a frame with its transmit antenna pattern directed towards the RSUS and with the TA and the RA fields in the MAC header set to the MAC address of the source RUS and destination RUS, respectively. Kapseok Chang, ETRI
Data Transmission Rules (3/4) • After Ptime+dTSR from the start of T2, the source RUS retransmits the same frame sent to the RSUS during the previous time T1 but now with its transmit antenna pattern directed towards the destination RUS. • Similarly, after Ptime+(dTDS-dTDR) from the start of T2, the RSUSrelays the same frame it received from the source RUS during the previous time T1 with its transmit antenna pattern directed towards the destination RUS. Kapseok Chang, ETRI
Data Transmission Rules (4/4) • So that the destination RUS can take advantage of the improved received signal level from both of these transmissions, the destination RUS should set its receive antenna pattern during T2 such that it simultaneously covers the links towards both the source RUS and the RSUS. • The Ack policy used during an SP where link cooperation is in use is the same as defined in clause 9. Kapseok Chang, ETRI
Relay Operation-type Change (ROC) Kapseok Chang, ETRI