doc.: IEEE Submission, Slide 1 Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [Versatile MAC for Body Area Network ] Date Submitted: [4 May, 2009] Source: [J.S Yoon, Gahng S. Ahn, Myung J Lee, Seong-soon Joo] Company [CUNY, ETRI] Address [140th St. and Convent Ave, New York, NY, USA ] Voice:[ ], FAX: [], Re: [Versatile MAC for BAN proposal responding to TG6 Call for Proposals ( tg6- call-proposals) ] Abstract:[This document describes a Versatile MAC that is being proposed to the TG6 group ] Purpose:[Discussion in Task Group ] Notice:This document has been prepared to assist the IEEE P 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 P

doc.: IEEE Submission Versatile MAC for Body Area Networks June S Yoon, Gahng S Ahn, Myung J Lee, Seong S. Joo CUNY, ETRI, Slide 2

doc.: IEEE Submission Outline Motivation Challenges BAN MAC –Overview –Details of each period AD, CAP, Beacon, DTS, ETS, CAP Extension –Energy saving –Prioritization Performance Summary, Slide 3

doc.: IEEE Submission Motivation To design a simple MAC protocol to support various QoS for Body Area Networks, Slide 4

doc.: IEEE Submission Design Challenges QoS Assurance –High reliability and guaranteed latency requirement for real time data, especially vital data  Need deterministic structure Flexibility –Support various types (periodic, non-periodic, medical, entertainment…) of traffic, data rate and PHYs  Instantly adaptable to application’s requirements Energy efficiency –Less energy consumption especially for implanted device  Need efficient active/inactive scheduling, Slide 5

doc.: IEEE Submission Proposed BAN MAC Features Versatile MAC –Best breed of Contention based and TDMA –Supports various (burst, periodic, continuous) types of traffic Straightway reservation (Ad-CAP-Beacon) –Fast reservation and prompt adaption –Latency reduction for delay sensitive real time data Emergency data transmit slot –Highly adaptable to abrupt emergency data –Support high QoS and reliability Priority supported Low energy consumption, Slide 6

doc.: IEEE Submission Versatile MAC Overviews, Slide 7

doc.: IEEE Submission BSF (BAN Superframe) Ad (Advertisement) –Synch, interval, address CAP –Reservation, Non-periodic data Beacon –Synch, reservation status announcement DTP (Data Transmit Period) –DTS (Data Transmit Slot) Periodic data transmit by reservation –ETS (Emergency Data Transmit Slot) Periodic data & Emergency data, Slide 8

doc.: IEEE Submission Details of each period, Slide 9

doc.: IEEE Submission Advertisement The beginning of BSF (BAN Superframe) followed by contention access period Ban Coordinator (BC) broadcasts it at the beginning of BSF and contains basic information such as –Synchronization –BC (Ban Coordinator) address –Ad Interval, length of periods A newly joined node adjusts its clock, gets information on BC and BSF, Slide 10

doc.: IEEE Submission CAP Contention access period –Backoff and carrier sense to avoid collision –Prioritized back-off and carrier sense to serve higher priority first Data Transmission –Command frames for DTS reservation exchanged –Non-periodic data including alarm and periodic data failed to reserve DTS can be sent BC collects all the DTS requests and allocate them according to their priorities and slot availability –Allocate first available slot based on the priority order to prevent DTS shortage –Lower priority slots may be preempted by higher priority data, Slide 11

doc.: IEEE Submission Beacon BC Broadcasts beacon before DTP –Notifies sync, interval, length, DTS reservation status All the nodes that reserved DTS should listen beacon every AI to check reservation status changes Sequential Ad-CAP-Beacon enables straightway slot reservation and prompt accommodation to changes, Slide 12

doc.: IEEE Submission Comparison: Reservation delay (From data generation to slot assign confirm by beacon) Proposed approach –Min: 1 slot (7.68ms) Data generation at the end of CAP –Max: 129 slots (0.991s) Data generation at the beginning of beacon Beacon (1)+ AI (128) 15.4 based approach –Min: 120 slots (0.922s) Data generation at the end of CAP CFP & Inactive(119) + Beacon(1) –Max: 248 slots (1.905s) Data generation at the beginning of CFP CFP & Inactive(119) + BI(128) + Beacon(1) Difference = 119 slot, 0.91s Assume slot size and AI, BI are same (BO=6, SO=3, 128 slots) & reservation is done right away if data is generated during CAP, Slide 13

doc.: IEEE Submission Data Transmit Period TDMA Period for the latency-critical continuous and periodic data DTS (Data Transmit Slot) –Nodes transmit data at the slot assigned by BC ETS ( Emergency Data Transmit slot) –Contention access period –If any, emergency data is transmitted at this slot –A node assigned to this slot performs carrier sense first so as to prevent collision with emergency alarm –Enables urgent transmission for abrupt Emergency alarm, Slide 14

doc.: IEEE Submission Comparison: Alarm delay (From alarm generation to transmit) Assume slot size and AI, BI(15.4) are same (BO=6, SO=3, 128 slots) and All CFP and DTP are occupied Alarm delay decreases as the number of ETS slot increases, however, at the expense of increased delay (carrier sense time) of the ETS slot owners., Slide 15

doc.: IEEE Submission Options ECAP (CAP Extension) –The duration between the ends of DTP and AI –If power is not a concern for BC, it can stay awake and maintain CAP –All kinds of data can be transmitted including retransmission Batch ACK –Ack at the last active slot for all data transmission in DTP Delayed ACK –Ack for multiple-slot transmission from a same source, Slide 16

doc.: IEEE Submission Prioritization, Slide 17

doc.: IEEE Submission BAN Data Prioritization Prioritization based on QoS (latency) requirement –Priority 0: Emergency reaction alarm Emergency vital signs, Battery depletion,... –Priority 1: Medical Continuous data Latency critical data –E.g. EEG/ECG/EMG –Priority 2: Medical Routine data Reliability critical but lesser latency requirement –E.g. Temperature, blood pressure –Priority 3 : Non-medical Continuous data Video, audio –Priority 4 : Others  Priority classes are dictated by the applications, Slide 18

doc.: IEEE Submission Prioritized Transmit in DTP Priority based allocation –Higher priority data served first in case of contention among different priority traffics Emergency data transmission in ETS –Owner of the slot performs carrier sense before transmission –Alarms perform short random backoff and carrier sense winner takes the slot, loser try again at the next ETS or CAP T(Backoff+Carrier sense+Tx Alarm ) < T(Carrier sense Owner ), Slide 19

doc.: IEEE Submission Prioritized Transmit in CAP Higher priority data access channel first Prioritized back-off –Prioritized Back-off exponent = Min. Back-off exponent-1 –Constant –Raises the probability that emergency alarm takes less back- off duration than others. Prioritized carrier sense –Prioritized Carrier sense duration = Carrier sense duration x0.5 –Situation that normal and prioritized back-off starts at the same time with same duration, emergency alarm can captures channel first., Slide 20

doc.: IEEE Submission Energy Saving Coordinator –Goes into inactive If no activity is scheduled after CAP or DTP Sensor (continuous data) –Once DTS reservation is done, the node stay inactive period except for beacon and its reserved transmit time Sensor (routine data) –Wakeup only for report and transmit during CAP or CAP Extension whichever available first Sensor (Alarm) –Wakeup only for report and transmit during CAP, CAP Extension or ETS whichever available first, Slide 21

doc.: IEEE Submission Summary of BAN MAC, Slide 22

doc.: IEEE Submission Summary Versatile MAC –CAP: Contention period –DTP: TDMA period, Enables high QoS Straightway reservation –Fast reservation, adaptation –Latency reduction Emergency data transmit slot –Highly adaptable to abrupt emergency data –Support high QoS and reliability Priority supported, Slide 23