Submission Title: Pre-Arbitrated Slot Allocation (PASA) MAC Protocol Project: IEEE P802.15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: Pre-Arbitrated Slot Allocation (PASA) MAC Protocol Date Submitted: 9 Nov., 2004 Source: [Hyung Soo Lee (1), Cheol Hyo Lee (1), Dan Keun Sung (2), Dong Jo Park (2), Joon Yong Lee (3), Chang Yong Jung (2), Jo Woon Chong (2), Min Jeong Kim (2), Sung Yoon Jung (2), Mi Kyung Oh (2)] Company: [(1) Electronics and Telecommunications Research Institute (ETRI) (2) Korea Advanced Institute of Science and Technology (KAIST) (3) Handong Global University (HGU)] Address: [(1) 161 Gajeong-dong, Yuseong-gu, Daejeon, Republic of Korea (2) 373-1 Guseong-dong, Yuseong-gu, Daejeon, Republic of Korea (3) Heunghae-eup, Buk-gu, Pohang, Republic of Korea] Voice: [(1) +82 42 860 5625, (2) +82 42 869 3439 (5439), (3) +82 54 260 1931], FAX: [(2) +82 42 864 3830] E-Mail: [(1) hsulee@etri.re.kr, (2) dksung@ee.kaist.ac.kr, cyjung@cnr.kaist.ac.kr, (3) joonlee@handong.edu] Abstract: [This document proposes preliminary proposal for the IEEE 802.15.4 alternate PHY standard] Purpose: [Preliminary Proposal for the IEEE802.15.4a standard] Notice: This document has been prepared to assist the IEEE P802.15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P802.15

Pre-Arbitrated Slot Allocation (PASA) MAC Protocol ETRI-KAIST-HGU Republic of Korea

Contents CSMA/CA in a UWB Impulse Environment Requirements for a New Energy-Efficient MAC Protocol Pre-Arbitrated Slot Allocation (PASA) MAC Protocol Performance Comparisons of PASA and CSMA/CA Simultaneously Operating Piconets (SOP) Conclusions

CSMA/CA in a UWB Impulse Environment Difficulties in Carrier Sensing Detection of UWB Impulse signals Integration and decision  detection error and delay Longer Clear Channel Assessment (CCA) detection time (d=30m, False Alarm Probability =0.1) Relatively Large Amount of Power Consumption Carrier sensing (CCA) overhead Tx, Rx, CCA, and idle states for the most of contention access period (CAP) CCA Detection Time 1 ms 2 ms 4 ms 8 ms CCA Detection Probability 0.37 0.53 0.77 0.92

Requirements for a New Energy-Efficient MAC Protocol No Carrier Sensing No CCA overhead Reduced Number of Node States Tx, Rx, and sleep Group Management Support for a large number of nodes Traffic load balancing Very Low User Activity Low Complexity Low Cost Contention Access Period and Contention Free Period

Pre-Arbitrated Slot Allocation (PASA) MAC Protocol Superframe Structure Beacon Period Contention Access Period (CAP) Pre-Arbitrated Slot Allocation (PASA) Contention Free Period (CFP) Time Division Multiple Access (TDMA) Beacon CAP CFP PASA TDMA Active Inactive

Pre-Arbitrated Slot Allocation (PASA) MAC Protocol (Cont’d) Pre-Arbitrated Slot Allocation for Each Group No CCA Elimination of CCA and idle states Grouping Nodes Support for a large number of nodes Efficient Energy Management Active state only if nodes transmit or receive frames Group Acknowledgement via the next available beacon Hierarchical Backoff Algorithm Intra-superframe backoff : random slot selection in the superframe Inter-superframe backoff : binary exponential superframe backoff

Pre-Arbitrated Slot Allocation (PASA) MAC Protocol (Cont’d) Operation Random Slot Selection Random Slot Selection Pre-Arbitrated Slot Allocation CAP

Node States in Both PASA and CSMA/CA Node States in PASA Tx : transmit data Rx : listen to beacon, receive data Sleep : except for Tx and Rx states Node States in CSMA/CA Rx : listen to beacon, receive ACK, and receive data CCA : perform CCA Idle : ready to transmit or receive Sleep : inactive state

Superframe Structure For Performance Evaluation Active Inactive CAP CFP PASA TDMA BEP = 256 (ms) CAP = 3072 (ms) CFP = 768 (ms) SD = 4096 (ms) BI = 8192 (ms) Assumptions Tb = 1 (ms), TimeSlot (TS) = 256 (ms) Superframe Duration (SD) = 4096 (ms) Beacon Interval (BI) = 8192 (ms) Beacon extension period (BEP) : 1 superframeslot = 256 (ms) CAP : 12 superframeslots = 3072 (ms) CFP : 3 superframeslots = 768 (ms) FER : 0.08

Power Consumption Model (Example) Power Consumption Assumed for Various Node States MAC Power State *Zigbee CSMA/CA PASA Tx state 31 mW Rx state 35 mW CCA state - 33 mW Idle state 30 mW Sleep state 10 mW * G. Lu, B. Krishnamachari, and C.S. Raghavendra,”Performance Evaluation of the IEEE 802.15.4 MAC for Low-Rate Low-Power Wireless Networks”, EWCN ‘04

Performance Measures Throughput # of Bits per Energy (bits/Joule) Successfully transmitted bits per second Focus on the CAP period # of Bits per Energy (bits/Joule) Average Delay From the frame generation time to the reception time of ACK for successful frame transmission : power consumption in state for node : steady state probability of state for node : the number of sensor nodes

Performance Comparisons of PASA and CSMA/CA (1) Throughput Channel activity factor per node : 10-3 Channel activity factor per node : 10-4

Performance Comparisons of PASA and CSMA/CA (2) Bits per Energy (bits/mJ) Channel activity factor per node : 10-3 Channel activity factor per node : 10-4

Performance Comparisons of PASA and CSMA/CA (3) Average Delay Channel activity factor per node : 10-3 Channel activity factor per node : 10-4

Simultaneously Operating Piconets (SOP) Time Division Operating bandwidth 3.1-4.9 GHz can be fully used (UWB pulse) Configuration of SOPs Self configuration of SOPs is possible by scanning the channel Piconet #1 Active Inactive Piconet #2 Piconet #3

Conclusions Pre-Arbitrated Slot Allocation (PASA) MAC Protocol No carrier sensing Reduced number of node states Tx, Rx, and sleep states Active only if nodes transmit or receive frames Scalability Group management Energy efficiency at the cost of delay Candidate for a MAC protocol based on UWB impulse radio