Wireless Body Area Networks. WiserBAN Smart miniature low-power wireless microsystem for Body Area Networks.

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1 Wireless Body Area Networks WiserBAN Smart miniature low-power wireless microsystem for Body Area Networks

2 Wireless Body Area Networks (WBANs) WBAN: Collection of nodes placed on, or inside, the human body (but not limited to). Nodes have sensing and/or actuating and communication capabilities. Applications: Medical: monitoring vital parameters, hearing aids, cardiac implant, etc. Sport/Fitness: rehabilitation, motion capture, monitoring parameters; Entertainment: consumer electronics (audio/video streaming, interactive gaming), personal item tracking.

3 Wireless Body Area Networks (WBANs) Application Requirements: Requirements may be very different depending on the application

4 Standard IEEE IEEE Task Group 6 (November 2007): Define the Physical (PHY) and Medium Access Control (MAC) Layers for short range, low complexity, low cost, ultra-low power and high reliable wireless communication in, on or around the human body. High level application requirements 7

5 Standard IEEE Riccardo Cavallari DEI, Università di Bologna Physical (PHY) Layer 3 different PHY Japan North America Australia Europe New Zeland Japan WorldWide HBC MICS WMTS ISM ISM UWB f [MHz] 2.45GHz Packet Component Modulation Symbol Rate (ksps) Spreading Factor (S) Narrowband Information Data Rate (kbps) PSDU π/2-dbpsk PSDU π/2-dbpsk PSDU π/2-dbpsk PSDU π/4-dqpsk N of 2.45GHz: 79 Channel of 1MHz Bandwidth Min Tx Power: -10 dbm EIRP Receiver 2.45GHz: Frequency Band (MHz) Information Data Rate (kbps) Minimum Sensitivity (dbm)

6 Standard IEEE MAC Access Modes / 1 1. Beacon Mode with superframe: beacons at the beginning of each superframe to establish a common time base for time referenced allocations; Random Access Phases Contention between nodes: allocations are non-recurring time intervals valid per instance of access. EAP (Exclusive Access Phase): for high priority traffic. RAP (Random Access Phase): for regular traffic. CSMA/CA Access Method: Backoff counter (BC) in the interval [0-CW], BC is decremented by one, for each successive idle CSMA time slot; When BC=0, the node obtains a contended allocation during which the TX occurs. Slotted Aloha Access Method: Contention Probability (CP) properly set; z =random in the interval [0-1]; If z CP the node obtains a contended allocation in the current Aloha slot, during which the TX occurs. 13

7 Standard IEEE MAC Access Modes / 2 Riccardo Cavallari DEI, Università di Bologna 2. Non-Beacon Mode with superframes: no beacons but superframe and allocation slots are established because the channel access involves time referencing. Only MAP. 3. Non-Beacon Mode without superframes: no beacons; superframe and allocation slots are not established because the allocation involves no time referencing. Unscheduled Access Method: A hub may provide unscheduled reoccuring polled or posted allocations, nodes may use CSMA/CA to obtain a contended allocation. 7

8 WiserBAN Project WiserBAN EU Project: realizes a miniaturized and ultra-low power RF microsystem, for medical and multimedia applications. T 4.3 T 4.2 T 4.1

9 WiserBAN after three years: SiP First chips are coming out First functional 2D-SiP for implantable devices. Left: 2D-SiP after assembly and Right: 2D-SiP after embedding. The final size of the 2D-SiP is 4.2mmx4.3mmx0.77mm.

10 WiserBAN after three years: SiP 3D SiP. From bottom down: SoC, piezo and antenna modules 2D-SiP on characterization board 3D SIP close-up

11 WiserBAN after three years: Antennas Photographs of the first L-antenna prototypes Radiation pattern of the L-antenna near human head New design of the micro SD antenna Directivity pattern for the smartphone scenario

12 WiserBAN after two years: Antennas Passive micro-sd antenna for WBAN remote control node Active frequency agile dipole antenna for ITE hearing aid Loop antenna integrated in cochlea implant

13 WiserBAN after three years: Radio

14 WiserBAN Project WiserBAN EU Project: aim is to develop a BAN protocol architecture that: Provides optimized power consumption while providing support for identified application requirements Supports coexistence and as much as possible cooperation and compliance with other BAN/PAN protocol architectures.

15 MAC protocol: Architecture

16 MAC protocol: Superframe mode Synchronous MAC High traffic applications CSMA/CA CSMA/CA Slotted ALOHA Beacon POLL (Indicators) RELAYING CFP (TDMA) CAP (CSMA/CA or Slotted ALOHA) ACK Inactive (Sleep) Beacon

17 MAC protocol: LPL mode Asynchronous MAC Low traffic, low energy applications TX ON T 1 IDLE P P P P A C K Data Frame A C K = TX t RX ON = RX Active Sleep P A C K Data Frame A C K IDLE T on T w T data t

18 MAC protocol: Implementation (*) This transitionimplies the channel selection procedure throughenergy detection. (**) This transitionimplies the Passive/Active scan procedure. FULL FUNCTION DEVICE REDUCED FUNCTION DEVICE LOW POWERDEVICE mac_init(mac_extended_address_t address) INITIALIZED MLME_RESET_REQUEST COORDINATOR MLME_TDMA_START_REQUEST (*) READY MLME_RESET_REQUEST All states MLME_SYNC_REQUEST (**) MLME_TDMA_START_REQUEST SYNCHRONIZATION MLME_SYNC_REQUEST MLME_BEACON_NOTIFY_INDICATION LPL SYNCHRONIZED MLME_SYNC_LOSS_INDICATION SYNCHRONIZATION LOST MLME_LPL_START_REQUEST All statesbut INITIALIZED MLME_ASSOCIATE_CONFIRM MLME_DISASSOCIATE_CONFIRM ASSOCIATED MLME_SYNC_LOSS_INDICATION

19 Experimental Setup Implementation and tests of the superframe CAP portion 3 end devices + 1 coordinator Right Ear Left Ear B e a c o n CSMA/CA CSMA/CA Slotted Aloha Inactive B e a c o n Remote Control Right Hip T CAP =60 ms t Superframe (SF), 75 ms RC `

20 Performance Evaluation Metrics Average packet delay Packet lost rate Energy consumption

21 Experimental Results Impact of Radio Channel

22 PL R CSMA/CA Body shadowing: PLR Measurement Results: PLR for each link 0.14 Packet Loss Rate 0.12 link 1: right ear link 2: left ear link 3: heart Right Ear Left Ear link 4: left hip 0.1 average Heart 0.08 Left Hip 0.06 Remote Control Payload size [Byte]

23 Experimental Results Comparing the Different Protocols

24 Protocol Comparison: Average Delay

25 Protocol Comparison: PLR

26 Experimental Results Low-Power-Listening MAC

27 Low-Power-Listening MAC Star topology composed of 1,2 or 3 EDs and one Coordinator. RC 3 2 C 1 ` ED 1 ED 3 Traffic: ED 2

28 MAC protocol: LPL mode Asynchronous MAC Low traffic, low energy applications TX ON T 1 IDLE P P P P A C K Data Frame A C K = TX t RX ON = RX Active Sleep P A C K Data Frame A C K IDLE T on T w T data t

29 Average energy consumed per packet [mj/packe LPL: Energy Consumption Transmitter Receiver RX, 20 Bytes RX, 60 Bytes RX, 100 Bytes TX, 20 Bytes TX, 60 Bytes TX, 100 Bytes T w [ms]

30 Average packet delay [ms] LPL: Average Delay Bytes 60 Bytes 20 Bytes T w [ms]

31 Throughput [kbit/s] LPL: Throughput Ideal MAC LPL peer-to-peer LPL Star 2 TX LPL Star 3 TX Offered load [kbit/s]

32 Wireless Sensor Networks Chiara Buratti

Radio Networks. Riccardo Cavallari. Radio Networks Office: 3 rd floor, Main Building

Radio Networks. Riccardo Cavallari. Radio Networks Office: 3 rd floor, Main Building Radio Networks riccardo.cavallari@unibo.it +39 051 20 93180 Office: 3 rd floor, Main Building 1 Wireless Body Area Networks (WBAN) and IEEE 802.15.6 Standard 2 Outline 1. Introduction Definitions and Application