Unit – III Wireless PAN’s (IEEE 802.15x)

Introduction to IEEE 802.15x Technologies Wireless PAN Applications & Architecture Bluetooth Link Controller Basics Evolution of 802.15 standards

Introduction to IEEE 802.15x Technologies April 2002  IEEE 802.15.1 (PHY & MAC specifications) for WPAN (Wireless Personal Area Network) WPAN – transfer data over short distance(10 m) between devices Goals – wireless connectivity for fixed, mobile, portable devices in POS POS (Personal Operating Space) - space around individual (10 m in all directions) - bubble around the user WPAN v/s WLAN

WLAN is to extend the reach of a wired LAN WPAN connection between that involves little or no physical infrasturucture or direct connectivity to the world outside of the link WPAN can achieved thr small ,extremely power efficient ,battery operated, low cost, solutions for wide and diverse range of personal devices. IEEE 802.15.1 specs. adopted from Bluetooth specs. - 1990 – Bluetooth SIG (Special Interest Group) - Stakeholders – IBM, Intel, Nokia, Toshiba, Ericsson, 3COM Microsoft, Agere, Motorola

Wireless PAN’s Applications & Architecture Basic WPAN Characteristics Bluetooth WPAN Overview Bluetooth WPAN Ad-Hoc Network Topologies Components of Bluetooth Architecture

Basic WPAN Characteristics – WPAN Power Levels & Coverage Area - WLAN (100mW power, 100 m, fixed & wired AP) - WPAN (1mW, 10 m, mobile & portable devices) – WPAN Media Control Techniques - PAN – different types of devices with different QOS - ad hoc networks controlled by single master & many slaves - time multiplexed slotted system – slaves poll for bandwidth - A WPAN device is required to maintain a management information database (MIB) to facilitate end to end network operations of a large infrastructure. – WPAN Network Lifespan - WLAN (infinite Lifespan using AP) - WPAN – master must, no master no n/w – finite lifespan, ad hoc & temporary conn.

Bluetooth WPAN Overview a WPAN provides support for both asynchronous communication channel for data transfer and asynchronous communication channel for telephony grade voice communication. - Bluetooth – short range radio link, battery operated devices compact & personal devices - Band Used – 2.4 GHz unlicensed ISM band, Binary Frequency Shift Keying (BFSK) mod. - Spread Spectrum – FHSS (1600 hops/s or 625 µs/hop) - A slotted channel format is used with a slot (a hop) duration 625µs. This allows for full duplex operation using a fast time division duplex (TDD) scheme

- Single-Slot Bluetooth Packet -Data traffic have maximum asymmetric rate of 723.2 kbps between two devices. - Bidirectional ,synchronous 64 kbps channels are able to support voice traffic between two devices

Bluetooth WPAN Ad-Hoc Network Topologies - Piconet (Bluetooth master & slave) - master – clock sync., frequency hopping scheme – point-to-point / point-to-multipoint

Bluetooth WPAN Ad-Hoc Network Topologies - Scatternet (piconet’s overlapping time & space) - Flow of information beyond single piconet area

Bluetooth WPAN Ad-Hoc Network Topologies - Integration of IEEE 802.15 & 802.11 networks

Components of Bluetooth Architecture - Bluetooth Protocol Stack – comm. protocols & interoperable applications

Bluetooth Link Controller Basics Bluetooth System Components Bluetooth Timeslot Format Types of Physical Links Packet Formats Transmitter/Receiver Timing Bluetooth Channel Control

Bluetooth System Components - Bluetooth protocol – circuit switched + packet switched data - Slotted format – Synchronous packet + Asynchronous traffic - Traffic – 3 simultaneous synchronous voice channels – sync. voice traffic + async. Data – async. data 723.2 kbps (ul) + 57.6 kbps (dl) – symmetric mode – data rate - 433.9 kbps (ul,dl) Link Manager

Bluetooth Timeslot Format - Bluetooth Channel – 625 µs timeslots - bluetooth devices – clock counter (0 to 227–1) - Transmission (Master – even timeslots, slave – odd timeslots - TDD Scheme -

Bluetooth Timeslot Format - Bluetooth multi-slot packet transmission -

Types of Physical Links – SCO (Synchronous Connection-Oriented) Link - symmetric, point-to-point, setup on reserved slots - circuit-switched connection, used for voice traffic - master 3SCO link slave, slave 3SCO link master - SCO link created by master, slave reply SCO packet – ACL (Asynchronous Connectionless) Link - point-to-multipoint, setup on non reserved SCO slots - packet switched connection - master–slave(only 1 ACL link)

Packet Formats  Access Code Types - CAC (Channel Access Code) identify & sync piconet, present in every packet - DAC (Device Access Code) signaling paging & paging response - IAC (Inquiry Access Code) - GIAC(General IAC)–discover bluetooth devices range - DIAC(Dedicated IAC) – discover bluetooth devices in range & with common characteristics

Packet Formats  Packet Header Details - AM_ADDR – 3 bit Active Member address - TYPE – 4 bit Type code - Flow – 1 bit flow control - ARQN –1 bit ack indication - SEQN – 1bit sequence number - HEC – 8 bit Header Error Check

Packet Formats  Packet Types SCO Packets - ACL Packets

Transmitter/Receiver Timing - use of master clock - used during & operation of piconet

Bluetooth Channel Control – The Bluetooth Clock (time & frequency hopping) - free running, never adjusted, not turned off - master device Bluetooth clock as reference

Evolution of IEEE 802.15 Standards 802.15.1 - short range wireless connectivity, moderate data rate, voice - 802.15.1a revision – backward compatibility, interoperability (WPAN & WLAN) 802.15.2 - revised project – 2003 - co-existence of WLAN & WPAN in same spectrum - Collaborative (TDMA or algorithm adapting to traffic types) - Non-Collaborative (no cooperation, interoperability)

IEEE 802.15.3 & 802.15.3a - adopted in 2003, WPAN-HR with QoS - low cost, complexity, power, high data rate(20 mbps) – Physical Layer

IEEE 802.15.3 & 802.15.3a – Piconets - Several Devices (DEV’s) - PNC (piconet co-ordinator) [timing via beacon frames, (Qos of piconet, power saving mode] - Dependent piconet, Parent piconet , Child piconet - Starting piconet  scan channels & beacon from PNC  collect info. of parent, child piconet  becomes PNC  transmit beacon frame in superframe - Superframe – beacon frame (time allocation, mgmt. info.) + CAP (communicate command & data) + CTAP (allocation of CTA’s to DEV)

IEEE 802.15.4 - Low Rate-WPAN (data rate-250kbps, ultra low power, low cost, low form factor, low complexity) -used for WSN – Physical Layer

IEEE 802.15.4 – Piconets (2 wireless topologies) - Star topology – home applications(PAN, FFD, RFD) - Peer-to-Peer – industrial, commercial(NC, FFD, RFD) Star Topology Peer-to-Peer Topology

IEEE 802.15.4 – Piconets Cluster-Tree Network Topology

IEEE 802.15.4 – SuperFrame Structure & MAC PDU