what is mobile computing? wireless communication systems mobile communication systems architecture...

What is Mobile Computing? Wireless Communication Systems Mobile Communication Systems Architecture Key Technologies of Mobile Computing Applications

Heterogeneous Wireless Communication World DAB: Digital Audio Broadcast VHE: Virtual Home Environment DVB-T: Digital Video Broadcast Terrestrial UMTS: Universal Mobile Telecommunication System

W IRELESS N ETWORKS Wireless communication networks IEEE 802.11 IEEE 802.15 IEEE 802.16 IEEE 802.20 Mobile communication networks GSM GPRS WCDMA HSPA+ LTE

IEEE 802 Refers to a family of IEEE standards dealing with local area networks and metropolitan area networks The services and protocols specified in IEEE 802 map to the lower two layers Data Link Logical Link Control (LLC) Media Access Control (MAC) Physical IEEE 802.11 IEEE 802.15 IEEE 802.16 IEEE 802.20

IEEE 802 Standards

WWAN / WMAN / WLAN / WPAN

Note: NFC (Near Field Communication) A short-range high frequency wireless communication technology which enables the exchange of data between devices over about a 10 centimetre (around 4 inches) distance The technology is a simple extension of the ISO/IEC 14443 proximity-card standard (contactless card, RFID) that combines the interface of a smartcard and a reader into a single device

An NFC device can communicate with both existing ISO/IEC 14443 smartcards and readers, as well as with other NFC devices, and is thereby compatible with existing contactless infrastructure already in use for public transportation and payment NFC technology is currently mainly aimed at being used with mobile phones

Three main use cases for NFC card emulation: the NFC device behaves like an existing contactless card reader mode: the NFC device is active and read a passive RFID tag, for example for interactive advertising P2P mode: two NFC devices are communicating together and exchanging information

Applications Mobile ticketing in public transport an extension of the existing contactless infrastructure Mobile payment the device acts as a debit/ credit payment card Smart poster the mobile phone is used to read RFID tags on outdoor billboards in order to get info on the move Bluetooth pairing pairing of Bluetooth devices with NFC bringing them close together and accepting the pairing

Other applications Electronic ticketing airline tickets, concert/event tickets, and others Electronic money Travel cards Identity documents Mobile commerce Electronic keys car keys, house/office keys, hotel room keys, etc. NFC can be used to configure and initiate other wireless network connections such as Bluetooth, Wi-Fi or Ultra-wideband

IEEE 802.11 Standard and Amendments IEEE 802.11 - The WLAN standard was original 1 Mbit/s and 2 Mbit/s, 2.4 GHz RF and infrared [IR] standard (1997), all the others listed below are Amendments to this standard, except for Recommended Practices 802.11F and 802.11T. IEEE 802.11a - 54 Mbit/s, 5 GHz standard (1999, shipping products in 2001) IEEE 802.11b - Enhancements to 802.11 to support 5.5 and 11 Mbit/s, 2.4 GHz (1999) IEEE 802.11c Bridge operation procedures; included in the IEEE 802.1D standard (2001) IEEE 802.11d - International (country-to-country) roaming extensions (2001) IEEE 802.11e - Enhancements: QoS, including packet bursting (2005) IEEE 802.11f - Inter-Access Point Protocol (2003) Withdrawn February 2006 IEEE 802.11 IEEE 802.15 IEEE 802.16 IEEE 802.20

IEEE 802.11g - 54 Mbit/s, 2.4 GHz standard (backwards compatible with b) (2003) IEEE 802.11h - Spectrum Managed 802.11a (5 GHz) for European compatibility (2004) IEEE 802.11i - Enhanced security (2004) IEEE 802.11j - Extensions for Japan (2004) IEEE 802.11-2007 - A new release of the standard that includes amendments a, b, d, e, g, h, i & j. (July 2007) IEEE 802.11k - Radio resource measurement enhancements (2008) IEEE 802.11n - Higher throughput improvements using MIMO (multiple input, multiple output antennas) (September 2009) IEEE 802.11p - WAVE Wireless Access for the Vehicular Environment (such as ambulances and passenger cars) (working June 2010) IEEE 802.11r - Fast roaming Working "Task Group r" - (2008) IEEE 802.11s - Mesh Networking, Extended Service Set (ESS) (working September 2010)

IEEE 802.11T Wireless Performance Prediction (WPP) - test methods and metrics Recommendation cancelled IEEE 802.11u - Interworking with non-802 networks (for example, cellular) (working September 2010) IEEE 802.11v - Wireless network management (working June 2010) IEEE 802.11w - Protected Management Frames (September 2009) IEEE 802.11y - 3650-3700 MHz Operation in the U.S. (2008) IEEE 802.11z - Extensions to Direct Link Setup (DLS) (August 2007 - December 2011) IEEE 802.11aa - Robust streaming of Audio Video Transport Streams (March 2008 - June 2011) IEEE 802.11mb Maintenance of the standard. Expected to become 802.11-2011. (ongoing) IEEE 802.11ac - Very High Throughput < 6 GHz (September 2008 - December 2012) IEEE 802.11ad - Extremely High Throughput 60 GHz (December 2008 - December 2012)

IEEE 802.11 / Wi-Fi [/ Wa Fa /] Wireless Fidelity ( ) A wireless-technology brand owned by the Wi-Fi alliance Promotes standards with the aim of improving the interoperability of wireless local area network products based on the IEEE 802.11 standards

Common applications for Wi-Fi Internet and VoIP phone access, gaming network connectivity for consumer electronics such as televisions, DVD players, and digital cameras Wi-Fi Alliance a consortium of separate and independent companies agrees on a set of common interoperable products based on the family of IEEE 802.11 standards

IEEE 802.11 Infrastructure Mode Uses fixed base stations (infrastructure) which are responsible for coordinating communication between the mobile hosts (nodes)

IEEE 802.11 Ad Hoc Mode Mobile nodes communicate with each other through wireless medium without any fixed infrastructure

Mobile Ad Hoc Networks (MANET) Host moves frequently Topology changes frequently No cellular infrastructure Multi-hop wireless links Data must be routed via intermediate nodes A B A B

802.11 /11a/11b/11g/11n

IEEE 802.11n Improve network throughput over 802.11a and 802.11g with a significant increase in the maximum raw data rate from 54 Mbit/s to 600 Mbit/s with the use of four spatial streams at a channel width of 40 MHz In spatial multiplexing a high rate signal is split into multiple lower rate streams each stream is transmitted from a different transmit antenna in the same frequency channel

802.11n uses MIMO (Multiple Input Multiple Output)

IEEE 802.11p (VANET) Motivation Vehicular Ad hoc NETwork (VANET) Safety on US highways (2004) 42,800 fatalities, 2.8 million injuries ~$230.6 billion cost to society Efficiency traffic jams waste time and fuel in 2003, US drivers lost a total of 3.5 billion hours and 5.7 billion gallons of fuel to traffic congestion Profit safety features and high-tech devices have become product differentiators

VANET-based Emergency Vehicle Warning System http://www.youtube.com/watch?v=yqtLvZrz2qE http://www.youtube.com/watch?v=yqtLvZrz2qE Ford's "Talking" Vehicles - Car-to-Car Communication Demo http://www.youtube.com/watch?v=XBqCAVwQv0E http://www.youtube.com/watch?v=XBqCAVwQv0E BMW Car-to-X Communication http://www.youtube.com/watch?v=JzgwlXzO6v0 http://www.youtube.com/watch?v=JzgwlXzO6v0 InfoFueling network http://www.youtube.com/watch?v=Cc19mcnzvpE * Ford Demonstrates Vehicle-to-Vehicle Communication for Increased Safety http://www.youtube.com/watch?v=RrCyl6pOAC0 http://www.youtube.com/watch?v=RrCyl6pOAC0

What is VANET?

Components in a VANET Moving vehicles with On-Board Unit (OBU) Road Side Units (RSU) local broadcasting information IEEE 802.11 access point RSU

On-Board Unit (OBU) Vehicle OBU WinXP devices Windows mobile PDAs GPS tracker without user interface Text-based OBUs Pedestrian OBU GPS phone Personal tracker

Smart Vehicle A modern vehicle is a network of sensors/actuators on wheels !

VANET Architecture

Differences between VANET and MANET VANETsMANETs Highly mobile nodes moving in the same or opposite directions Nodes move randomly Network shape can be best described by either a one-dimensional line or a strip A square or torus shape With location information and mapWithout location information Rely heavily on broadcast transmission to disseminate traffic related information to all reachable nodes (one to all & all to all) A query for a route to a certain host (one to one & one to all) Energy supported by carEnergy supported by battery (Energy conservation) EmergencyNon-emergency Topology changes frequentlyTopology changes slowly

Vehicle Communication (VC) VC promises safer roads

more efficient driving

more fun

VANET Applications Congestion detection Vehicle platooning Road conditions warning Collision alert Stoplight assistant Emergency vehicle warning Deceleration warning Toll collection Border clearance Adaptive cruise control Drive-through payment Merge assistance

A Taxonomy of Vehicular Communication Systems

Communication Types Roadside-to-Vehicle Communications (RVC) Inter-Vehicle Communications (IVC) Hybrid-Vehicle Communications (HVC) +

I NTER - VEHICLE COMMUNICATION (IVC) S YSTEMS Completely infrastructure-free Only onboard units (OBUs) are needed

IVC SYSTEMS SIVC (Single-hop Inter-Vehicle Communication) applications of short-range communications e.g., lane merging, automatic cruise control MIVC (Multihop Inter-Vehicle Communication) applications of long-range communications e.g., traffic monitoring (a) SIVC(b) MIVC

R OADSIDE - TO -V EHICLE C OMMUNICATION (RVC) S YSTEMS Communication between roadside infrastructure (RSU) and OBU Two types of infrastructures Sparse RVC (SRVC) system Ubiquitous RVC (URVC) system

RVC S YSTEMS - SRVC Provide communication services at hot spots Examples a busy intersection scheduling its traffic light a gas station advertising its existence (and prices) parking availability at an airport

RVC S YSTEMS - URVC Provide all roads with high-speed communication Require considerable investments for providing full (even significant) coverage of existing roadways

H YBRID V EHICULAR C OMMUNICATION (HVC) S YSTEMS Extend the transmission range of RVC systems Vehicles communicate with roadside infrastructure even when they are not in direct wireless range by using other vehicles as mobile routers

HVC Adv. & Disadv. Advantage less roadside infrastructure Disadvantage network connectivity may not be guaranteed in scenarios with low vehicle density

Vehicular Ad Hoc Network (VANET) Message propagates to destination using a number of intermediate links

If vehicle mobility causes links to break, message rerouted using a different path

Challenges Physical layer limited bandwidth Link layer congestion control, latency, throughput, fairness and scalability Network (routing) layer rapid topology changes and network fragmentation

WAVE (IEEE 1609) / DSRC (802.11 P )

WAVE (W IRELESS A CCESS IN V EHICULAR E NVIRONMENTS )

WAVE IEEE 1609 Mode of operation used by IEEE 802.11 devices to operate in the DSRC band (5.850-5.925 GHz) Defines architecture communications model management structure security and physical access Primary architecture components are OBU, RSU, and WAVE interface

P1609.1 Resource Manager P1609.2 Security Services for Applications and Management Messages P1609.3 Networking Services P1609.4 Multi-Channel Operations VAVE Standard Components

WAVE (IEEE 1609) / DSRC (802.11 P )

DSRC (D EDICATED S HORT R ANGE C OMMUNICATIONS ) ASTM Standard E2213-03, based on IEEE 802.11a Name of the 5.9 GHz Band allocated for the ITS communications 5.855-5.925 GHz range divided into 7 licensed channels (each 10 MHz) Short range radio 300m (1000m max) High data rate 6-27 Mbps ASTM: American Society for Testing and Materials

Half-duplex station can only send or transmit, but not both at the same time Latency 200 s Communication modes vehicle to roadside & vehicle to vehicle DSRC devices IEEE 802.11 systems using the WAVE mode of operation in the DSRC band

Based on ASTM Standard E2213-03 IEEE 802.11a PHY: OFDM modulation IEEE 802.11 MAC: CSMA/CA IEEE 802.11e MAC enhancement: message prioritization IEEE 802.11p Basis

Longer ranges of operation (up to ~1000 meters) High speed vehicles (up to ~500 km/h) Extreme multipath environment (many reflections with long delays) Need multiple overlapping ad-hoc networks to operate with extremely high quality of service Support automotive applications (e.g. reliable broadcast) IEEE 802.11p Requirements

Control Channel (CCH) broadcast communication dedicated to short, high-priority, data and management frames safety-critical communication with low latencies initialization of two-way communication on SCH Service Channel (SCH) two-way communication between RSU and OBU or between OBUs specific applications, e.g. tolling, internet access different kinds of applications can be executed in parallel on different service channels IEEE 802.11p Multi-Channel

DSRC C HANNEL A LLOCATION 7 licensed channels (each 10 MHz)

DSRC C HANNEL A LLOCATION

H OW DSRC W ORKS ? RSU announces to OBUs 10 times per second the applications it supports OBU listens on channel 172 authenticates RSU digital signature executes safety apps first then, switches channels executes non-safety apps returns to channel 172 and listens

IEEE 1609.4 E XTENSION FOR MULTI - CHANNEL COORDINATION

C HANNEL C OORDINATION Each Universal Time Coordinated (UTC) second is split into 10 Sync Intervals (each 100ms) Every Sync Interval is composed of alternating CCH Interval (50ms): all WAVE devices have to monitor the CCH SCH Interval (50ms): nodes may switch to a SCH (RX or TX) Synchronization is performed via GPS

IEEE 802.11 P M EDIA A CCESS C ONTROL (MAC) Based on Distributed Control Function (DCF) with CSMA/CA CSMA/CA if the channel is sensed busy before transmission then the transmission is deferred for a random interval Basic access mode and RTS/CTS mode are used on SCH

DCF: BASIC ACCESS MODE A node transmits a DATA packet if it senses the channel to be idle The receiver upon receiving an error-free packet, returns an ACK The sender if the transmitting node does not get an ACK back, it enters into back-off and retransmits after the back-off period Basic access mode suffers from hidden node problem

ABC H IDDEN N ODE PROBLEM A is sending to B C is ready to transmit to B it does not detect carrier and thus begins transmission this produces a collision at B Cs carrier sense did not provide the necessary information since station A was hidden from it RTS/CTS solves the hidden terminal problem!

DCF: RTS/CTS MODE When a node A wants to send a packet to node B, it initially sends a Request-to-Send (RTS) A

Upon correctly receiving the RTS, node B responds with Clear-to-Send (CTS) B

After receiving the CTS, node A sends the DATA packet to node B B A

If node B receives the DATA packet correctly, it sends an Acknowledgment (ACK) back to node A Any node that hears an RTS or a CTS is prohibited from transmitting any signal for a period that is encoded in the duration field of the received RTS or CTS

The duration fields in RTS and CTS are set such that nodes A and B will be able to complete their communication within the prohibited period (Network Allocation Vector, NAV) Finally, if a node does not get a response to an RTS or a DATA packet, it enters into an exponential backoff mode

The dark bars below node C and D indicates their NAV

B ACKOFF I NTERVAL When channel is busy, choose a backoff interval in the range [0, cw] Count down the backoff interval when medium becomes idle Count down is suspended if medium becomes busy again When backoff interval reaches 0, transmit RTS Binary exponential backoff in 802.11 DCF when a node fails to receive CTS, cw is doubled up (up to an upper bound, cw max ) when a data transfer completes successfully, cw is reset to cw min

IEEE 802.11 P MAC C HANNEL A CCESS

IEEE 802.15 The 15 th working group of the IEEE 802 and specializes in Wireless PAN (Personal Area Network) standards IEEE 802.15.1 IEEE 802.15.1-2002 a Wireless PAN standard based on Bluetooth v1.1 specifications including a media access control and physical layer specification IEEE 802.15.1-2005 based upon the additions incorporated into Bluetooth v1.2 IEEE 802.11 IEEE 802.15 IEEE 802.16 IEEE 802.20

the IEEE Study Group discontinues their relationship with the Bluetooth SIG (the later versions of Bluetooth will not become future IEEE standards) Bluetooth specifications Bluetooth 1.0 and 1.0B Bluetooth 1.1 Bluetooth 1.2 (data rate: 1Mbps) [not IEEE standard] Bluetooth 2.0 + EDR (Extended Data Rate) Bluetooth 2.1 + EDR (data rate: 3Mbps) Bluetooth 3.0 + HS (High Speed) (data rate: perhaps 24Mbps) Bluetooth V4.0 (Ble; Bluetooth low energy) (data rate: perhaps 24Mbps)

IEEE 802.16 Standards (WiMAX) IEEE 802.11 IEEE 802.15 IEEE 802.16 IEEE 802.20

802.16 WiMAX (Worldwide Interoperability for Microwave Access ) WirelessMAN A telecommunications technology aimed at providing wireless data over long distances in a variety of ways, from point-to-point links to full mobile cellular type access Enable the delivery of last mile wireless broadband access as an alternative to cable and DSL

Intel WiMAX Vision 82

WiMAX for Fixed and Mobile Access 83 CPE (Customer Premise Equipment) /

WiMAX Consumer Last Mile 84

WiMAX Backhaul for Business 85

WiMAX Nomadic / Portable 86

2008.11.13 HTC Max 4G GSM / WiMAX 88

IEEE 802.16 Operation Modes / Topologies Point to MultiPoint (PMP) / star topology Mesh mode / mesh topology Mobile Multihop Relay (MMR) / tree topology

IEEE 802.16 Entities BS Base Station central role in PMP mode coordination role in resource management connection/gateway point to other networks (backhaul, core IP, Internet) SS Subscriber Station fixed station MS mobile station MSS - Multiple Subscriber Station (playing role of an AP for LAN/WLAN) in-door or out-door RS Relay station used in Mobile Multihop Relay (MMR) 90

802.16 Relevant Standards 802.16d (2004) basic fixed mode- standard PMP / mesh modes, 70 Mbps 802.16e (2005) (Mobile WiMAX) lower data rate, 15 Mbps full nomadic and mobile use including handover enhancements to 802.16-2004 better support for QoS scalable OFDMA supports devices : mobile smart phones, PDAs, notebooks, laptops 91

802.16j Mobile Multihop Relay (MMR) enhance the normal PMP frame structure backward compatible with PMP mode new relay networking protocols multi-hop relay connections between SS/MS and BS coverage extensions throughput enhancement actually not mesh mode but tree topology 93

802.16m amendment for advanced air interface based on IEEE 802.16e-2005 expected data rates 100 Mbps for mobile applications 1 Gbps for fixed applications spectral efficiency, improve voice capacity, reduce latency support for location-based services improve multicast broadcast services 94

IEE 802.16 Relevant Standards Evolution 95

96 Mobile WiMAX (IEEE 802.16e) To enable low-cost mobile Internet applications To realize the convergence of mobile and fixed broadband access in a single air interface and network architecture

Mobile WiMAX enabling a variety of usage models in the same network

Mobile WiMAX Technology and Network Evolution Roadmap

WiMAX Network Reference Model

WiMAX Logical Network Entities Mobile Station (MS) generalized user equipment set providing wireless connectivity between a single or multiple hosts and the WiMAX network in this context the term MS is used more generically to refer to both mobile and fixed device terminals

Access Service Network (ASN) a complete set of network functions required to provide radio access to MS layer 2 (L2) connectivity with the MS according to IEEE 802.16 standards and WiMAX system profile transfer of authentication, authorization, and accounting (AAA) messages to the home network service provider (HNSP) preferred NSP discovery and selection relay functionality for establishing layer 3 (L3) connectivity with MS (i.e., IP address allocation) radio resource management to enable mobility, the ASN may also support ASN and CSN anchored mobility, paging and location management, and ASN-CSN tunneling

Base station (BS) primarily consists of radio related functions of an ASN interfacing with an MS over-the-air link according to MAC and PHY specifications ASN gateway (ASN-GW) an aggregation of centralized functions related to QoS, security, and mobility management for all the data connections served by its association with BSs through R6 hosts functions related to IP layer interactions with CSN through R3 interacts with other ASNs through R4 in support of mobility

Connectivity Service Network (CSN) a set of network functions that provide IP connectivity services to WiMAX subscriber(s) the CSN may further comprises network elements such as routers, AAA proxy /servers, home agent, and user databases as well as interworking gateways or enhanced network servers to support multicast and broadcast services and location-based services

key functions IP address management AAA proxy or server QoS policy and admission control based on user subscription profiles ASN-CSN tunneling support subscriber billing and interoperator settlement inter-CSN tunneling for roaming CSN-anchored inter-ASN mobility connectivity to Internet and managed WiMAX services such as IP multimedia services (IMS), location-based services, peer-to-peer services, and broadcast and multicast services over-the-air activation and provisioning of WiMAX devices

105 WiMAX Reference Points R1 SS/MS ASN 802.16e R2 SS/MS CSN IP R3 ASN CSN AAA R4 ASN R5 CSN AAA Billing R6 BS ASN BS ASN R8 BS

WiMAX Network uses IP Based Simple Protocol Structure SS/MS ASN CSN BSASN-GW

MAC / PHY Protocol Structure in Mobile WiMAX Release 1.0

WiMAX MAC Layer (IEEE Std. 802.16-2004)

Service Specific Convergence Sublayer (CS) MAC MAC CS (Service Access Point SAP) IEEE 802.16-2004 sub-layer (SDU) sub-layer (PDU) Common Part Sublayer (CPS) CPS MAC sublayer CPS MAC SAP CS QoS 802.16 MAC MAC CPS Security Sublayer (SS) Key /

110 WiMAX Network Architecture and Evolution (Release 1.0) ASN and CSN mobility (for mobility support) Paging and location management IPv4 and IPv6 connectivity Preprovisioned/static QoS Optional radio resource management (RRM) Network discovery/selection IP/Ethernet CS support Flexible credentials, pre- and postpaid accounting Roaming (RADIUS only) 3GPP I-WLAN compatible interworking

111 Over-the-air (OTA) activation and provisioning Location-based services (LBS) Multicast broadcast service (MBS) IMS integration Dynamic QoS and policy and charging (PCC) compatible with 3GPP Release 7 Telephony VoIP with emergency call services and lawful interception Full NAP sharing support Handover data integrity Multihost support Ethernet services, VLAN Enhanced open Internet services Diameter-based AAA WiMAX Network Architecture and Evolution (Release 1.5)

112 Multimedia session continuity 3GPP/2 interworking (optimized handover ) Network management, including self- organized /optimized networks (SONs) Seamless WiFi-WiMAX handover Roaming enhancements Support for multihop relay stations Support for femto-cells Device reported metrics WiMAX Network Architecture and Evolution (Release 2.0)

802.20 MBWA (Mobile Broadband Wireless Access) IEEE 802.20 or Mobile Broadband Wireless Access (MBWA) an IEEE Standard to enable worldwide deployment of multi-vendor interoperable mobile broadband wireless access networks a packet-based air interface designed for IP-based services low-cost, always-on, and mobile broadband wireless networks, nicknamed as Mobile-Fi the goals of 802.20 and 802.16e, the so-called "mobile WiMAX", are similar IEEE 802.11 IEEE 802.15 IEEE 802.16 IEEE 802.20

Technical description IP roaming & handoff (more than 1 Mbps) new MAC and PHY with IP and adaptive antennas optimized for full mobility up to vehicular speeds of 250 km/h operates in licensed bands (below 3.5 GHz) utilizes packet architecture low latency

WWAN / WMAN / WLAN / WPAN

what is mobile computing? wireless communication systems mobile communication systems architecture...

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