Wireless Application Protocol

Outline Mobile applications How are mobile/wireless environments different? What is WAP? WAP Architecture WAE (WML/WMLScript) WTA Framework WAP Push Services WAP Protocol Stack Hype v/s Reality References and Resources

Mobile Applications - 1 Vehicles Emergencies Traveling salesmen transmission of news, road condition etc ad-hoc network with near vehicles to prevent accidents Emergencies early transmission of patient data to the hospital ad-hoc network in case of earthquakes, cyclones military ... Traveling salesmen direct access to central customer files consistent databases for all agents mobile office

Mobile Applications - 2 Web access Information services outdoor Internet access intelligent travel guide with up-to-date location dependent information Information services push: stock quotes; pull: nearest cash ATM Disconnected operations file-system caching for off-line work mobile agents, e.g., shopping Entertainment games, etc

Variability of the Mobile Environment Mobility stationary nomadic (pedestrian speed) mobile (vehicular speed) roaming (mobile across networks) Connectivity connected semi-connected (asymmetric) weakly connected disconnected Mobile Device Capability form factor GUI multimedia real-time multimedia

World Wide Web and Mobility HTTP/HTML have not been designed for mobile applications/devices HTTP 1.0 characteristics designed for large bandwidth, low delay stateless, client/server, request/response communication connection oriented, one connection per request TCP 3-way handshake, DNS lookup overheads big protocol headers, uncompressed content transfer primitive caching (often disabled, dynamic objects) security problems (using SSL/TLS with proxies) HTML characteristics designed for computers with “high” performance, color high-resolution display, mouse, hard disk typically, web pages optimized for design, not for communication; ignore end-system characteristics

System Support for Mobile WWW Enhanced browsers client-aware support for mobility Proxies Client proxy: pre-fetching, caching, off-line use Network proxy: adaptive content transformation for connections Client and network proxy Enhanced servers server-aware support for mobility serve the content in multiple ways, depending on client capabilities New protocols/languages WAP/WML

Wireless Application Protocol (WAP) Empowers mobile users with wireless devices to easily access and interact with information and services. A “standard” created by wireless and Internet companies to enable Internet access from a cellular phone wapforum.org: co-founded by Ericsson, Motorola, Nokia, Phone.com 450 members in 2000, comprise of Handset manufacturers, Wireless service providers, ISPs, Software companies in the wireless industry Goals deliver Internet services to mobile devices enable applications to scale across a variety of transport options and device types independence from wireless network standards GSM, CDMA IS-95, TDMA IS-136, 3G systems (UMTS, W-CDMA)

WAP: Main Features Browser Markup language Script language Gateway “Micro browser”, similar to existing web browsers Markup language Similar to HTML, adapted to mobile devices Script language Similar to Javascript, adapted to mobile devices Gateway Transition from wireless to wired world Server “Wap/Origin server”, similar to existing web servers Protocol layers Transport layer, security layer, session layer etc. Telephony application interface Access to telephony functions

Internet Model HTML HTTP TLS/SSL TCP/IP

WAP Architecture Web Server WAP Gateway Client HTTP WSP/WTP Content CGI Scripts etc. with WML-Script WML Decks WAP Gateway WML Encoder WMLScript Compiler Protocol Adapters Client WML WML-Script WTAI Etc. HTTP WSP/WTP Source: WAP Forum

WAP Application Server Client WML WML-Script WTAI Etc. WAP Application Server WML Encoder WMLScript Compiler Protocol Adapters Application Logic WSP/WTP with WML-Script WML Decks Content Source: WAP Forum

WAP Architecture Key Components Another look Origin/Web Server WAP Gateway/Proxy WAP Protocol Stack Micro Browser WML/WML Script Transcoders WTA Source: WAP Forum

WAP: Network Elements fixed network wireless network Internet WAP proxy WML Binary WML HTML filter WML HTML HTML filter/ WAP proxy Binary WML web server HTML WTA server Binary WML PSTN Binary WML: binary file format for clients Source: Schiller

WAP Specifies Wireless Application Environment Wireless Protocol Stack WML Microbrowser WMLScript Virtual Machine WMLScript Standard Library Wireless Telephony Application Interface (WTAI) WAP content types Wireless Protocol Stack Wireless Session Protocol (WSP) Wireless Transport Layer Security (WTLS) Wireless Transaction Protocol (WTP) Wireless Datagram Protocol (WDP) Wireless network interface definitions

WAP Stack Source: WAP Forum Runs on top of WDP Provided lightweight X-oriented service Unreliable 1-way request Reliable 1-way/2-way req./response MicroBrowser (WML, WMLScript, WTA, WTAI) Lightweight SSL Uses WIM/PKI-Cards Datagram service on different bearers Convergence between bearer services Different Wireless Tech. Source: WAP Forum

WAP Stack WAE (Wireless Application Environment): Architecture: application model, browser, gateway, server WML: XML-Syntax, based on card stacks, variables, ... WTA: telephone services, such as call control, phone book etc. WSP (Wireless Session Protocol): Provides HTTP 1.1 functionality Supports session management, security, etc. WTP (Wireless Transaction Protocol): Provides reliable message transfer mechanisms Based on ideas from TCP/RPC WTLS (Wireless Transport Layer Security): Provides data integrity, privacy, authentication functions Based on ideas from TLS/SSL WDP (Wireless Datagram Protocol): Provides transport layer functions Based on ideas from UDP Content encoding, optimized for low-bandwidth channels, simple devices

WHY WAP? Wireless networks and phones WAP have specific needs and requirements not addressed by existing Internet technologies WAP Enables any data transport TCP/IP, UDP/IP, GUTS (IS-135/6), SMS, or USSD. Optimizes the content and air-link protocols Utilizes plain Web HTTP 1.1 servers leverages existing development methodologies utilizes standard Internet markup language technology (XML) all WML content is accessed via HTTP 1.1 requests WML UI components map well onto existing mobile phone user interfaces no re-education of the end-users leveraging market penetration of mobile devices Several modular entities together form a fully compliant Internet entity

Why is HTTP/HTML not enough? Big pipe - small pipe syndrome Wireless network <HTML> <HEAD> <TITLE>NNN Interactive</TITLE> <META HTTP-EQUIV="Refresh" CONTENT="1800, URL=/index.html"> </HEAD> <BODY BGCOLOR="#FFFFFF" BACKGROUND="/images/9607/bgbar5.gif" LINK="#0A3990" ALINK="#FF0000" VLINK="#FF0000" TEXT="000000" ONLOAD="if(parent.frames.length!=0)top.location='http://nnn.com';"> <A NAME="#top"></A> <TABLE WIDTH=599 BORDER="0"> <TR ALIGN=LEFT> <TD WIDTH=117 VALIGN=TOP ALIGN=LEFT> Internet <WML> <CARD> <DO TYPE="ACCEPT"> <GO URL="/submit?Name=$N"/> </DO> Enter name: <INPUT TYPE="TEXT" KEY="N"/> </CARD> </WML> 010011010011110110010011011011011101010010011010 Content encoding HTTP/HTML WAP Source: WAP Forum

WAP: “Killer” Applications Location-based services Real-time traffic reporting, Event/restaurant recommendation Enterprise solutions Email access, Database access, “global” intranet access Information updates “pushed” to WAP devices Financial services Banking, Bill-paying, Stock trading, Funds transfers Travel services Schedules and rescheduling, Reservations Gaming and Entertainment Online, real-time, multi-player games Downloadable horoscopes, cartoons, quotes, advice M-Commerce Shopping on the go Instant comparison shopping Location-based special offers and sales

Wireless Application Environment (WAE) Goals device and network independent application environment for low-bandwidth, wireless devices considerations of slow links, limited memory, low computing power, small display, simple user interface (compared to desktops) integrated Internet/WWW programming model high interoperability

WAE Components Architecture User Agents WML WMLScript WTA Application model, Microbrowser, Gateway, Server User Agents WML/WTA/Others content formats: vCard, vCalendar, Wireless Bitmap, WML, ... WML XML-Syntax, based on card stacks, variables, ... WMLScript procedural, loops, conditions, ... (similar to JavaScript) WTA telephone services, such as call control, text messages, phone book, ... (accessible from WML/WMLScript) Proxy (Method/Push)

WAE: Logical Model Origin Servers Gateway Client Method proxy WTA user agent web server response with content encoded response with content Push proxy WML user agent other content server push content encoded push content encoders & decoders other WAE user agents request encoded request

WAP Microbrowser Optimized for wireless devices Minimal RAM, ROM, Display, CPU and keys Provides consistent service UI across devices Provides Internet compatibility Enables wide array of available content and applications

WML: Wireless Markup Language Tag-based browsing language: Screen management (text, images) Data input (text, selection lists, etc.) Hyperlinks & navigation support Takes into account limited display, navigation capabilities of devices XML-based language describes only intent of interaction in an abstract manner presentation depends upon device capabilities Cards and Decks document consists of many cards User interactions are split into cards Explicit navigation between cards cards are grouped to decks deck is similar to HTML page, unit of content transmission Events, variables and state mgmt Content (XML) XSL Processor WML Browsers WML Stylesheet HTTP Browser HTML StyleSheet

WML WML File Structure <?xml version="1.0"?> The basic unit is a card. Cards are grouped together into Decks Document ~ Deck (unit of transfer) All decks must contain Document prologue XML & document type declaration <WML> element Must contain one or more cards WML File Structure <?xml version="1.0"?> <!DOCTYPE WML PUBLIC "-//WAPFORUM//DTD WML 1.0//EN" "http://www.wapforum.org/DTD/wml.xml"> <WML> ... </WML>

WML Example Deck Card Navigation Variables Input Elements <WML> <DO TYPE=“ACCEPT”> <GO URL=“#eCard”/> </DO Welcome! </CARD> <CARD NAME=“eCard”> <GO URL=“/submit?N=$(N)&S=$(S)”/> </DO> Enter name: <INPUT KEY=“N”/> Choose speed: <SELECT KEY=“S”> <OPTION VALUE=“0”>Fast</OPTION> <OPTION VALUE=“1”>Slow</OPTION> <SELECT> </WML> Deck Card Navigation Variables Input Elements

A Deck of Cards Acme Inc. Directory _____________ Next Services <WML> <CARD> <DO TYPE="ACCEPT" LABEL="Next"> <GO URL="#card2"/> </DO> Acme Inc.<BR/>Directory </CARD> <CARD NAME="card2"> <DO TYPE="ACCEPT"> <GO URL="?send=$type"/> Services <SELECT KEY="type"> <OPTION VALUE="em">Email</OPTION> <OPTION VALUE="ph">Phone</OPTION> <OPTION VALUE="fx">Fax</OPTION> </SELECT> </WML> Acme Inc. Directory _____________ Next Services 1>Email 2 Phone ____________ OK Source: WAP Forum

The DO Element Binds a task to a user action Action type: ACCEPT, OPTIONS, HELP PREV, DELETE, RESET Label: Text string or image (optional) Task: GO PREV, REFRESH, NOOP Destination: URL Post data: if METHOD=POST <DO TYPE="ACCEPT" LABEL="Next"> <GO URL="http://www.mysite.com/myapp.wml"/> </DO> Source: WAP Forum

Anchored Links Bind a task to the ACCEPT action, when cursor points to a link TITLE= sets the label string (default = “Link”) Links are not allowed in select list options <CARD> Please visit our <A TITLE="Visit"> <GO URL="home.wml"/>home page</A> for details. </CARD> Please visit our home page for ____________ Visit Source: WAP Forum

The TEMPLATE Element Defines actions & events for all cards in a deck <WML> <TEMPLATE> <DO TYPE="OPTIONS" LABEL="Main"> <GO URL="main_menu.wml"/> </DO> </TEMPLATE> <CARD NAME="msg1"> <DO TYPE="ACCEPT" LABEL="Next"> <GO URL="#msg2"/> First story </CARD> <CARD NAME="msg2"> Second story </WML> First story … _____________ Next Main Second story ... _____________ OK Main Source: WAP Forum

Handling User Input Select lists Input fields KEY variables Choose from a list of options Input fields Enter a string of text or numbers KEY variables Set by SELECT and INPUT elements How user input is passed to other cards and the application server Source: WAP Forum

The SELECT Element Display a list of options Each option may set the KEY variable and/or bind a task to the ACCEPT key TITLE= dynamically sets the label string MULTIPLE=“TRUE”: Allows user to pick multiple items <CARD> <DO TYPE="ACCEPT" LABEL="View"> <GO URL="getcity.cgi?location=$city"/> </DO> Forecast <SELECT KEY="city"> <OPTION VALUE="ber">Berlin</OPTION> <OPTION VALUE="rom">Rome</OPTION> <OPTION TITLE="Find" ONCLICK="find.cgi">New City</OPTION> </SELECT> </CARD> Forecast 1 Berlin 2 Rome 3>New City ____________ Find Source: WAP Forum

The INPUT Element Prompts user to enter a string of text DEFAULT=key_value; Default KEY variable (displayed to user) FORMAT=format_specifier; If omitted, free-form entry is allowed EMPTYOK="TRUE“; Browser will accept null input TYPE="PASSWORD“; Special entry mode handled by the browser MAXLENGTH=number; Maximum number of allowed characters Soc. Security: 287-33- _ ____________ NUM <CARD> <DO TYPE="ACCEPT"> <GO URL="?get=person" METHOD="POST" POSTDATA="userid=$ssn"/> </DO> Soc Security: <INPUT KEY="ssn" FORMAT="NNN\-NN\-NNNN"/> </CARD> Soc. Security: 287-33- 7629 ____________ OK Source: WAP Forum

WML Content Formats Common interchange formats, for interoperability Business cards: IMC vCard standard Calendar: IMC vCalendar standard Images: WBMP (Wireless BitMaP) Compiled WML, WMLScript Newly defined formats: WML text and tokenized format WMLScript text and bytecode format WBMP image format Binary format for size reduction Bytecodes/tokens for common values and operators Compressed headers Data compression (e.g. images) General-purpose transport compression can still be applied

Displaying Images Insert app images or local icons within display text 1-bit BMP format Images are ignored by non-bitmapped devices Check HTTP_ACCEPT for “image/bmp” <CARD> <DO TYPE="ACCEPT"> <GO URL="#c2"/> </DO> Continue <IMG LOCALSRC="righthand" ALT="forward..."/> </CARD> <CARD NAME="c2"> <IMG SRC="../images/logo.wbmp" ALT="Unwired Planet"/> <BR/>Welcome! Source: WAP Forum

WML (other features) Setting card styles to create forms Using variables to cache user data Using card intrinsic events to trigger transparent tasks Using timers Securing WML decks Bookmarking decks

WMLScript Complement to WML Provides general scripting capabilities Derived from JavaScript™ Provides general scripting capabilities Procedural logic, loops, conditionals, etc. Optimized for small-memory, small-cpu devices Features local user interaction, validity check of user input access to device facilities (phone call, address book etc.) extensions to the device software configure device, download new functionality after deployment Bytecode-based virtual machine Stack-oriented design, ROM-able Designed for simple, low-impact implementation WMLScript compiler resides in the network

WMLScript Libraries Lang - VM constants, general-purpose math functionality, etc. String - string processing functions URL - URL processing Browser - WML browser interface Dialog - simple user interface Float - floating point functions

WMLScript Example Functions Variables Programming Constructs function currencyConvertor(currency, exchRate) { return currency*exchangeRate; } function myDay(sunShines) { var myDay; if (sunShines) { myDay = “Good”; } else { myDay = “Not so good”; }; return myDay; Variables Programming Constructs Source: WAP Forum

Wireless Telephony Application (WTA) Collection of telephony specific extensions designed primarily for network operators Example calling a number (WML) wtai://wp/mc;07216086415 calling a number (WMLScript) WTAPublic.makeCall("07216086415"); Implementation Extension of basic WAE application model Extensions added to standard WML/WMLScript browser Exposes additional API (WTAI)

WTA Features Extension of basic WAE application model WTAI includes: network model for interaction client requests to server event signaling: server can push content to the client event handling table indicating how to react on certain events from the network client may now be able to handle unknown events telephony functions some application on the client may access telephony functions WTAI includes: Call control Network text messaging Phone book interface Event processing Security model: segregation Separate WTA browser Separate WTA port

WTA Example (WML) Placing an outgoing call with WTAI: WTAI Call <CARD> <DO TYPE=“ACCEPT”> <GO URL=“wtai:cc/mc;$(N)”/> </DO> Enter phone number: <INPUT TYPE=“TEXT” KEY=“N”/> </CARD> </WML> WTAI Call Input Element Source: WAP Forum

WTA Example (WMLScript) Placing an outgoing call with WTAI: function checkNumber(N) { if (Lang.isInt(N)) WTAI.makeCall(N); else Dialog.alert(“Bad phone number”); } WTAI Call Source: WAP Forum

WTA Logical Architecture other telephone networks WTA Origin Server WTA & WML server WML Scripts WML decks WTA services Client WAE services WTA user agent mobile network WAP Gateway encoders & decoders network operator trusted domain other WTA servers third party origin servers firewall Source: Schiller

WTA Framework Components Source: Heijden

WTA User Agent WTA User Agent WTA User Agent Context WML User agent with extended functionality can access mobile device’s telephony functions through WTAI can store WTA service content persistently in a repository handles events originating in the mobile network WTA User Agent Context Abstraction of execution space Holds current parameters, navigation history, state of user agent Similar to activation record in a process address space Uses connection-mode and connectionless services offered by WSP Specific, secure WDP ports on the WAP gateway

WTA Events and Repository Network notifies device of event (such as incoming call) WTA events map to device’s native events WTA services are aware of and able to act on these events example: incoming call indication, call cleared, call connected WTA Repository local store for content related to WTA services (minimize network traffic) Channels: define the service content format defining a WTA service stored in repository XML document specifying eventid, title, abstract, and resources that implement a service Resources: execution scripts for a service could be WML decks, WML Scripts, WBMP images.. downloaded from WTA server and stored in repository before service is referenced Server can also initiate download of a channel

WTA Channels and Resources Source: Heijden

WTA Interface (public) generic, high-level interface to mobile’s telephony functions setting up phone calls, reading and writing entries in phonebook.. Public WTAI for third party WML content providers restricted set of telephony functions available to any WAE User Agent library functions make call: allows application to setup call to a valid tel number send DTMF tones: send DTMF tones through the setup call user notified to grant permission for service execution cannot be triggered by network events example: Yellow pages service with “make call” feature

WTA Interface (network) Network Common WTAI WTA service provider is in operator’s domain all WTAI features are accessible, including the interface to WTA events library functions Voice-call control: setup call, accept, release, send DTMF tones Network text: send text, read text, remove text (SMS) Phonebook: write, read, remove phonebook entry Call logs: last dialed numbers, missed calls, received calls Miscellaneous: terminate WTA user agent, protect context user can give blanket permission to invoke a function example: Voice mail service Network Specific WTAI specific to type of bearer network example: GSM: call reject, call hold, call transfer, join multiparty, send USSD

WTA Event Handling Event occurrence Event handling Event binding WTA user agent could be executing and expecting the event WTA user agent could be executing and a different event occurs No service is executing Event handling channel for each event defines the content to be processed upon reception of that event Event binding association of an event with the corresponding handler (channel) Global binding: channel corresponding to the event is stored in the repository event causes execution of resources defined by the channel example: voice mail service Temporary binding: resources to be executed are defined by the already executing service example: yellow pages lookup and call establishment

Event Handling (no service in execution) Source: Heijden

Event Handling (service already execution) 1: Temporary binding exists 2. No temporary binding and context is protected 3: No temporary binding and context is not protected Source: Heijden

WTA: Voice mail Example push deck WTA client WTA server mobile network voice mail server incoming voice message generate new deck display deck; user selects translate setup call wait for call accept call voice connection indicate new voice message request play requested voice message call indication Source: Schiller

WTA Application: Example (using WML) <CARD> <DO TYPE="ACCEPT" TASK="GO" URL="#voteChamp"/> Please vote for your champion! </CARD> <CARD NAME="voteChamp"> <DO TYPE="ACCEPT" TASK="GO" URL="wtai://cc/sc;$voteNo;1"/> Please choose: <SELECT KEY="voteNo"> <OPTION VALUE="6086415">Mickey</OPTION> <OPTION VALUE="6086416">Donald</OPTION> <OPTION VALUE="6086417">Pluto</OPTION> </SELECT> </WML> Source: Schiller

WTA: Example with WML and WMLScript function voteCall(Nr) { var j = WTACallControl.setup(Nr,1); if (j>=0) { WMLBrowser.setVar("Message", "Called"); WMLBrowser.setVar("No", Nr); } else { WMLBrowser.setVar("Message", "Error!"); WMLBrowser.setVar("No", j); WMLBrowser.go("showResult"); Source: Schiller

WTA: Example with WML and WMLScript <CARD> <DO TYPE="ACCEPT" TASK="GO" URL="#voteChamp"/> Please vote for your champion! </CARD> <CARD NAME="voteChamp"> <DO TYPE="ACCEPT" TASK="GO" URL="/script#voteCall($voteNo)"/> Please choose: <SELECT KEY="voteNo"> <OPTION VALUE="6086415">Mickey</OPTION> <OPTION VALUE="6086416">Donald</OPTION> <OPTION VALUE="6086417">Pluto</OPTION> </SELECT> <CARD NAME="showResult"> Status of your call: $Message $No </WML> Source: Schiller

WAP Push Services Web push Wireless push WAP push Scheduled pull by client (browser) example: Active Channels no real-time alerting/response example: stock quotes Wireless push accomplished by using the network itself example: SMS limited to simple text, cannot be used as starting point for service example: if SMS contains news, user cannot request specific news item WAP push Network supported push of WML content example: Alerts or service indications Pre-caching of data (channels/resources)

WAP Push Framework Source: Heijden

Push Access Protocol Based on request/response model Push initiator is the client Push proxy is the server Initiator uses HTTP POST to send push message to proxy Initiator sends control information as an XML document, and content for mobile (as WML) Proxy sends XML entity in response indicating submission status Initiator can cancel previous push query status of push query status/capabilities of device

Push Proxy Gateway WAP stack (communication with mobile device) TCP/IP stack (communication with Internet push initiator) Proxy layer does control information parsing content transformation session management client capabilities store and forward prioritization address resolution management function

Over the Air (OTA) Protocol Extends WSP with push-specific functionality Application ID uniquely identifies a particular application in the client (referenced as a URI) Connection-oriented mode client informs proxy of application IDs in a session Connectionless mode well known ports, one for secure and other for non-secure push Session Initiation Application (SIA) unconfirmed push from proxy to client request to create a session for a specific user agent and bearer

WAE Summary WML WMLScript WTA Push analogous to HTML (optimized for wireless) event based, microbrowser user agent WMLScript analogous to JavaScript features of compiler in the network WTA WTAI: different access rights for different applications/agents WTA User Agent (analogy with operating systems) Context – Activation Record Channel – Interrupt Handler Resource – Shared routines invoked by interrupt handlers Repository – Library of interrupt handlers feature of dynamically pushing the interrupt handler before the event Push no analogy in Internet

WAP Gateway Summary Encoders Filters Method Proxy Push Proxy translate between binary (WML) and text (HTML/WML) Filters transcoding between WML (wireless) and HTML (wired) Method Proxy similar to standard proxy services WAP stack on wireless interface and TCP/IP stack on Internet interface Push Proxy Push Access Protocol with Internet Push Initiator (Web Server) Over the Air Protocol with mobile device (and WAP Push Initiator) Performs necessary filtering, translation etc.

WAP Servers Summary Origin Server WAP Server WTA Server Web server with HTML/WML contents Runs TCP/IP stack, needs PAP protocol for push, no end-to-end security WAP Server Serves WML content Runs WAP stack, uses OTA protocol for push, end-to-end security possible WTA Server Specialized for telephony applications (runs WAP stack, uses push extensively) Client initiated (make call “hyperlink” from a Yellow pages service) Server intiated (incoming call from a Voice mail service)

WAP: Protocol Stack Bearers (GSM, CDPD, ...) Security Layer (WTLS) Session Layer (WSP) Application Layer (WAE) Transport Layer (WDP) TCP/IP, UDP/IP, media SSL/TLS HTML, Java HTTP Internet WAP WAE comprises WML (Wireless Markup Language), WML Script, WTAI etc. Transaction Layer (WTP) additional services and applications WCMP A-SAP S-SAP TR-SAP SEC-SAP T-SAP Source: Schiller

WDP: Wireless Datagram Protocol Goals create a worldwide interoperable transport system by adapting WDP to the different underlying technologies transmission services, such as SMS in GSM might change, new services can replace the old ones WDP Transport layer protocol within the WAP architecture uses the Service Primitive T-UnitData.req .ind uses transport mechanisms of different bearer technologies offers a common interface for higher layer protocols allows for transparent communication despite different technologies addressing uses port numbers WDP over IP is UDP/IP

WDP: Service Primitives T-SAP T-DUnitdata.req (DA, DP, SA, SP, UD) T-DUnitdata.ind (SA, SP, UD) T-DError.ind (EC) SAP: Service Access Point DA: Destination Address DP: Destination Port SA: Source Address SP: Source Port UD: User Data EC: Error Code Source: Schiller

Service, Protocol, and Bearer Example WAP Over GSM Circuit-Switched RAS - Remote Access Server IWF - InterWorking Function WSP WAE Subnetwork IP Apps on Other Servers WAP Proxy/Server CSD-RF PPP Mobile IWF PSTN Circuit ISP/RAS WTP UDP Any bearer which supports IP will be able to support WTP since WTP/T and in future WTP/C is defined for operation over UDP. The WTP/D service is UDP/IP. Note: UDP will require a new port number to be issued/reserved by IANA for WAP. After which the suite of WAP protocols will be distinguished by port numbers or protocol identifiers defined by the WAP Forum within the WAP UDP port number issued by IANA. Source: WAP Forum

Service, Protocol, and Bearer Example WAP Over GSM Short Message Service WAP Proxy/Server Mobile WAE WAE Apps on other servers WSP WSP SMSC WTP WTP WDP WDP SMS SMS WDP Tunnel Protocol WDP Tunnel Protocol Subnetwork Subnetwork under development Source: WAP Forum

WTLS:Wireless Transport Layer Security Goals Provide mechanisms for secure transfer of content, for applications needing privacy, identification, message integrity and non-repudiation Provide support for protection against denial-of-service attacks WTLS is based on the TLS/SSL (Transport Layer Security) protocol optimized for low-bandwidth communication channels provides privacy (encryption) data integrity (MACs) authentication (public-key and symmetric) Employs special adapted mechanisms for wireless usage Long lived secure sessions Optimised handshake procedures Provides simple data reliability for operation over datagram bearers

WTLS Internal Architecture Record Protocol Handshake Protocol Alert Protocol Application Protocol Change Cipher Spec Protocol Transaction Protocol (WTP) Datagram Protocol (WDP/UDP) Bearer networks WTLS Record protocol Note to translator: Here I am going to explain and talk about each of the protocol elements in the WTLS layer Source: WAP Forum

WTLS: Secure session, Full handshake SEC-Create.req (SA, SP, DA, DP, KES, CS, CM) SEC-Create.ind originator SEC-SAP peer SEC-Create.cnf (SNM, KR, SID, KES‘, CS‘, CM‘) SEC-Create.res SEC-Exchange.req SEC-Exchange.ind SEC-Exchange.res (CC) SEC-Commit.req SEC-Exchange.cnf SEC-Commit.ind SEC-Commit.cnf KES: Key Exchange Suite CS: Cipher Suite CM: Compression Mode SNM: Sequence Number Mode KR: Key Refresh Cycle SID: Session Identifier CC: Client Certificate Source: Schiller

WTLS: Transferring Datagrams sender SEC-SAP receiver SEC-SAP SEC-Unitdata.req (SA, SP, DA, DP, UD) SEC-Unitdata.ind (SA, SP, DA, DP, UD) Source: Schiller

WTP: Wireless Transaction Protocol Goals different transaction services that enable applications to select reliability, efficiency levels low memory requirements, suited to simple devices (< 10kbyte ) efficiency for wireless transmission WTP supports peer-to-peer, client/server and multicast applications efficient for wireless transmission support for different communication scenarios class 0: unreliable message transfer unconfirmed Invoke message with no Result message a datagram that can be sent within the context of an existing Session class 1: reliable message transfer without result message confirmed Invoke message with no Result message used for data push, where no response from the destination is expected class 2: reliable message transfer with exactly one reliable result message confirmed Invoke message with one confirmed Result message a single request produces a single reply

WTP Services and Protocols WTP (Transaction) provides reliable data transfer based on request/reply paradigm no explicit connection setup or tear down optimized setup (data carried in first packet of protocol exchange) seeks to reduce 3-way handshake on initial request supports header compression segmentation /re-assembly retransmission of lost packets selective-retransmission port number addressing (UDP ports numbers) flow control message oriented (not stream) supports an Abort function for outstanding requests supports concatenation of PDUs supports User acknowledgement or Stack acknowledgement option acks may be forced from the WTP user (upper layer) default is stack ack Since there is no connection setup phase there is no mechanism to negotiate parameters (actually some things can be negotiated but not in the full sense that a connection-oriented call setup would allow) to be used during the message exchange, such as packet size or window size (packet group). Therefore using WTP/T requires an a priori agreement between the mobile and server as to the default parameters to be used during a message exchange. Packet versus Streams -a packet interface allows the application more control over a partial transmission. It requires the application (Session layer) to segment its transmission data to fixed length packets, this allows the restarting of a failed transmission at the place of the last successful transmission - checkpointing. -a stream interface is what is most commonly implemented for TCP (sockets) and is widely used by TCP applications.

WTP Services and Protocols uses the service primitives T-TRInvoke.req .cnf. .ind .res T-TRResult.req .cnf .ind .res T-Abort.req .ind Client Server Invoke Ack Result T-TRInvoke.req T-TRResult.ind T-TRInvoke.cnf T-TRResult.res (PDUs) T-TRInvoke.ind T-TRResult.req T-TRInvoke.res T-TRResult.cnf Ack may be piggybacked on a Result packet, therefore the Ack is shown with a dotted line.

WTP Class 0 Transaction initiator TR-SAP responder TR-SAP TR-Invoke.req (SA, SP, DA, DP, A, UD, C=0, H) TR-Invoke.ind (SA, SP, DA, DP, A, UD, C=0, H‘) Invoke PDU A: Acknowledgement Type (WTP/User) C: Class (0,1,2) H: Handle (socket alias) Source: Schiller

WTP Class 1 Transaction, no user ack & user ack TR-Invoke.req (SA, SP, DA, DP, A, UD, C=1, H) Invoke PDU TR-Invoke.ind (SA, SP, DA, DP, A, UD, C=1, H‘) initiator TR-SAP responder Ack PDU TR-Invoke.cnf (H) TR-Invoke.req (SA, SP, DA, DP, A, UD, C=1, H) Invoke PDU TR-Invoke.ind (SA, SP, DA, DP, A, UD, C=1, H‘) initiator TR-SAP responder Ack PDU TR-Invoke.res (H‘) TR-Invoke.cnf (H) Source: Schiller

WTP Class 2 Transaction, no user ack, no hold on TR-Invoke.req (SA, SP, DA, DP, A, UD, C=2, H) Invoke PDU TR-Invoke.ind (SA, SP, DA, DP, A, UD, C=2, H‘) initiator TR-SAP responder Result PDU TR-Result.req (UD*, H‘) TR-Result.ind (UD*, H) Ack PDU TR-Invoke.cnf (H) TR-Result.res TR-Result.cnf (H‘) Source: Schiller

WTP Class 2 Transaction, user ack TR-Invoke.req (SA, SP, DA, DP, A, UD, C=2, H) Invoke PDU TR-Invoke.ind (SA, SP, DA, DP, A, UD, C=2, H‘) initiator TR-SAP responder Result PDU TR-Result.ind (UD*, H) Ack PDU TR-Invoke.res (H‘) TR-Invoke.cnf (H) TR-Result.req (UD*, H‘) TR-Result.res TR-Result.cnf Source: Schiller

WTP Class 2 Transaction, hold on, no user ack TR-Invoke.req (SA, SP, DA, DP, A, UD, C=2, H) Invoke PDU TR-Invoke.ind (SA, SP, DA, DP, A, UD, C=2, H‘) initiator TR-SAP responder Result PDU TR-Result.req (UD*, H‘) TR-Result.ind (UD*, H) Ack PDU TR-Invoke.cnf (H) TR-Result.res TR-Result.cnf (H‘) Source: Schiller

WSP - Wireless Session Protocol Goals HTTP 1.1 functionality Request/reply, content type negotiation, ... support of client/server transactions, push technology key management, authentication, Internet security services WSP Services provides shared state between client and server, optimizes content transfer session management (establish, release, suspend, resume) efficient capability negotiation content encoding push WSP/B (Browsing) HTTP/1.1 functionality - but binary encoded exchange of session headers push and pull data transfer asynchronous requests

HTTP 1.1 and WSP HTTP 1.1 WSP enhancements beyond HTTP Why Not HTTP? extensible request/reply methods extensible request/reply headers content typing composite objects asynchronous requests WSP enhancements beyond HTTP binary header encoding session headers confirmed and non-confirmed data push capability negotiation suspend and resume fully asynchronous requests connectionless service Why Not HTTP? encoding not compact enough, inefficient capability negotiation no push facility

WSP Overview Header Encoding Capabilities (are defined for): compact binary encoding of headers, content type identifiers and other well-known textual or structured values reduces the data actually sent over the network Capabilities (are defined for): message size, client and server protocol options: Confirmed Push Facility, Push Facility, Session Suspend Facility, Acknowledgement headers maximum outstanding requests extended methods header code pages Suspend and Resume server knows when client can accept a push multi-bearer devices dynamic addressing allows the release of underlying bearer resources

WSP Sessions Session Context and Push Connection-mode push can take advantage of session headers server knows when client can accept a push Connection-mode long-lived communication, benefits of the session state, reliability Connectionless-mode stateless applications, no session creation overhead, no reliability overhead

WSP/B session establishment client S-SAP server S-SAP S-Connect.req (SA, CA, CH, RC) S-Connect.ind (SA, CA, CH, RC) Connect PDU S-Connect.res (SH, NC) S-Connect.cnf (SH, NC) ConnReply PDU CH: Client Header RC: Requested Capabilities SH: Server Header NC: Negotiated Capabilities WTP Class 2 transaction Source: Schiller

WSP/B session suspend/resume client S-SAP server S-SAP S-Suspend.req S-Suspend.ind (R) Suspend PDU S-Suspend.ind (R) WTP Class 0 transaction ~ ~ R: Reason for disconnection S-Resume.req (SA, CA) S-Resume.ind (SA, CA) Resume PDU S-Resume.res Reply PDU S-Resume.cnf WTP Class 2 transaction Source: Schiller

WSP/B session termination client S-SAP server S-SAP S-Disconnect.req (R) S-Disconnect.ind (R) Disconnect PDU S-Disconnect.ind (R) WTP Class 0 transaction Source: Schiller

WSP/B method invoke client S-SAP server S-SAP S-MethodInvoke.req (CTID, M, RU) S-MethodInvoke.ind (STID, M, RU) Method PDU S-MethodInvoke.res (STID) S-MethodInvoke.cnf (CTID) S-MethodResult.req (STID, S, RH, RB) S-MethodResult.ind (CTID, S, RH, RB) Reply PDU S-MethodResult.res (CTID) S-MethodResult.cnf (STID) CTID: Client Transaction ID M: Method Invoked RU: Request URI STID: Server Transaction ID S: Response Status RH: Response Header RB: Response Body WTP Class 2 transaction Source: Schiller

WSP/B over WTP - method invocation client S-SAP initiator TR-SAP responder TR-SAP server S-SAP S-MethodInvoke.req TR-Invoke.req Invoke(Method) TR-Invoke.ind S-MethodInvoke.ind TR-Invoke.res S-MethodInvoke.res Ack PDU S-MethodInvoke.cnf TR-Invoke.cnf TR-Result.req S-MethodResult.req Result(Reply) S-MethodResult.ind TR-Result.ind S-MethodResult.res TR-Result.res Ack PDU TR-Result.cnf S-MethodResult.cnf Source: Schiller

WSP/B over WTP - asynchronous, unordered requests client S-SAP server S-SAP S-MethodInvoke_1.req S-MethodInvoke_2.req S-MethodInvoke_2.ind S-MethodInvoke_1.ind S-MethodInvoke_3.req S-MethodResult_1.req S-MethodInvoke_3.ind S-MethodResult_1.ind S-MethodResult_3.req S-MethodResult_3.ind S-MethodResult_2.req S-MethodInvoke_4.req S-MethodInvoke_4.ind S-MethodResult_4.req S-MethodResult_4.ind S-MethodResult_2.ind Source: Schiller

WSP/B - confirmed/non-confirmed push client S-SAP server S-SAP S-Push.req (PH, PB) S-Push.ind (PH, PB) Push PDU WTP Class 0 transaction PH: Push Header PB: Push Body SPID: Server Push ID CPID: Client Push ID client S-SAP server S-SAP S-ConfirmedPush.req (SPID, PH, PB) S-ConfirmedPush.ind (CPID, PH, PB) ConfPush PDU S-ConfirmedPush.res (CPID) S-ConfirmedPush.cnf (SPID) WTP Class 1 transaction Source: Schiller

WSP/B over WDP client S-SAP server S-SAP S-Unit-MethodInvoke.req (SA, CA, TID, M, RU) S-Unit-MethodInvoke.ind (SA, CA, TID, M, RU) Method PDU S-Unit-MethodResult.req (CA, SA, TID, S, RH, RB) S-Unit-MethodResult.ind (CA, SA, TID, S, RH, RB) Reply PDU S-Unit-Push.req (CA, SA, PID, PH, PB) S-Unit-Push.ind (CA, SA, PID, PH, PB) Push PDU WDP Unitdata service Source: Schiller

WAP Stack Summary WDP WTLS WTP WSP functionality similar to UDP in IP networks WTLS functionality similar to SSL/TLS (optimized for wireless) WTP Class 0: analogous to UDP Class 1: analogous to TCP (without connection setup overheads) Class 2: analogous to RPC (optimized for wireless) features of “user acknowledgement”, “hold on” WSP WSP/B: analogous to http 1.1 (add features of suspend/resume) method: analogous to RPC/RMI features of asynchronous invocations, push (confirmed/unconfirmed)

WAP: Ongoing Work WDP WTLS WTP WSP WAE Tunnel to support WAP where no (end-to-end) IP bearer available WTLS support for end-to-end security (extending WTLS endpoint beyond WAP Gateway) interoperable between WAP and Internet (public key infrastructure) integrating Smart Cards for security functions WTP efficient transport over wireless links (wireless TCP) bearer selection/switching quality of service definitions WSP quality of service parameters multicast data, multimedia support WAE User agent profiles: personalize for device characteristics, preferences etc Push architecture, asynchronous applications Billing

WAP: Hype vs Reality Low-bandwidth wireless links tcp/ip over wireless can also address these problems encoding in http can also reduce data transfer on wireless links Limited device capabilities Microbrowser is appropriate to address this problem WTAI features are not present in tcp/ip domain Challenges in WAP adapting to applications rich in content and interaction service guarantees interface design and usability Other approaches for WWW access through mobiles i-Mode (from NTT DoCoMo) WAP is a TRAP (http://www.freeprotocols.org/wapTrap)

References and Resources Books Mobile communications: Jochen Schiller, Addison Wesley 2000 Understanding WAP: Official Website (specifications) www.wapforum.org Technical/Developer Info and tools www.palopt.com.au/wap www.wap.net Major players www.nokia.com/wap www.ericsson.se/wap phone.com OpenSource effort www.wapgateway.org (Kannel WAP gateway project)

Thank You This presentation is available online from http://www.it.iitb.ernet.in/~sri/talks Sridhar Iyer KR School of Information Technology IIT Bombay

Is for “Wireless Fidelity” Or IEEE 802.11 Standard WiFi Is for “Wireless Fidelity” Or IEEE 802.11 Standard WiFi

What is the goal of 802.11 standard ? To develop a Medium Access Control (MAC) and Physical Layer (PHY) specification for wireless connectivity for fixed, portable and moving stations within a local area. WiFi

802.11 sub-standards(amendments ) …. 802.11 MAC (Media Access Control) ratified 1999 802.11b PHY 2.4 GHz (max 11 Mbps) ratified 1999 802.11a PHY 5.0 GHz (max 54 Mbps) ratified 1999 802.11g PHY 2.0 GHz (max 54 Mbps) ratified 2003 802.11i Security draft number XXX 802.11e QoS, Multimedia draft number XXX 802.11h European regulations for 5GHz draft number XXX 802.11h Japan regulations for 5GHz draft number XXX WiFi

Do I need any license to use 802.11 device ? No , 2.4 GHz and 5.0 GHz are public available frequency !!! WiFi

Context with OSI layers WiFi

Logical Link Control Services WiFi

Standard 802.11 frame format WiFi

Frames types and subtypes Three types of frames: Control (ACK,RTS,CTS ,Power Save …) Management (Beacon,Probe Request ,Probe Response, Association request , Association response …) Data (Data, Null Data, Data_CF_Ack , ….) WiFi

Infrastructure Model includes: (most common) Stations (STA) 802.11 MAC – Configuration summary – Infrastructure model Infrastructure Model includes: (most common) Stations (STA) any wireless device Access Point (AP) connects BSS to DS controls access by STA’s Basic Service Set (BSS) a region controlled by an AP mobility is supported within a single BSS Extended Service Set (ESS) a set of BSS’s forming a virtual BSS mobility is supported between BSS’s in an ESS Distribution Service (DS) connection between BSS’s BSS2 ESS1 DS AP2 AP3 AP1 STA3 STA1 BSS3 BSS1 STA2 WiFi

The 802.11 MAC supports infrastructure and ad hoc network models Ad Hoc Model includes: Stations (STA) any wireless device act as distributed AP Independent Basic Service Set (IBSS) BSS forming a self contained network no AP and no connection to the DS STA1 STA3 STA2 IBSS WiFi

Two types of access to air DCF (distributed coordination function ) means everybody can speak and try to get air : 100% on the market PCF (point coordination function) means ONE point coordinator (BOSS) who will allowed you to speak (like in bluetooth) WiFi

Summary of required features and difficulties vs 802.11 features High speed operation (PHY only) Fair access (DCF, PCF) Time-bounded access (PCF) Flexible configuration (BSS, IBSS) Security (WEP) Mobility support (ESS) Low power (PS) Difficulties Hidden terminals (RTS/CTS) Capture (CSMA/CA, ACK) Noise and interference (ACK, frag) Limited spectrum (licencing, PHYs) WiFi

The 802.11 MAC basic Distributed Co-ordination Function (DCF) access scheme uses a CSMA/CA based protocol If the STA detects the medium is busy when attempting to send a packet then: the STA starts a random back-off timer the randomisation parameters depend on previous transmission successes/failures the back-off timer runs once the medium has been idle for an IFS period An STA may transmit a packet after sensing the medium is idle for an Inter Frame Space (IFS) period the back-off timer suspends when the medium is busy and does not restart until medium is idle for an IFS period The STA may transmit when the back-off timer expires The state (busy or idle) of the medium is determined using: physical carrier sense virtual carrier sense, based on reservations in received packets. These reservations set the NAV timer. The medium is considered busy until the NAV timer expires WiFi

The 802.11 MAC basic Distributed Co-ordination Function (DCF) access scheme uses a CSMA/CA based protocol Medium busy Contention window Send frame IFS IFS Busy Frame Defer access while busy and for an IFS period Decrement back-off when medium idle for at least IFS period WiFi

Acknowledgment WiFi

Security WEP ( wired equivalent privacy) 64/128 bits Using RC4 algorithm, almost permanent key, very week security, able to crack by collecting statistic Current security level for 99.9% products on the market. TKIP (temporal key integrity protocol ) Used RC4 algorithm with with a 128-bit "temporal key" but changes temporal keys every 10,000 packets and key dependes on address and sequence number. Will be required to obtain WiFi certification from 09/01/03 AES (Advanced Encryption Standard ) New, much more stronger encryption, protect against hacker frames in insertion. Need hardware accelerator. Optional feature. WiFi

Why do we need 11A/11B/11G ? 11B: 2.4 GHz , CCK modulation Rates from 1 to 11Mbps , on market from 1999 11A: 5.0 GHz , OFDM modulation Rates from 6 to 56 Mbps , on market from 2002 11G: 2.4 GHz, CCK+OFDM modulation Rates from 6 to 56 Mbps, on market from 2003 and … most popular today !!! Advantages of 2.4 GHz PHY: Low frequency, better wall penetration, less sensitive to multipath 3 not-overlapped channels Advantages of 5.0 GHz PHY: Less devices on the market (no microwave, no blue tooth …) 8 not-overlapped channels Range: almost the same … WiFi

802.11 a/b/g performance 11A/G max throughput ~22 Mbps , not 54 Mbps (!!!) 11B max throughput ~6 Mbps WiFi

Wlan market Scenarios WiFi

IEEE 802.16 for MAN==Metropolitan Area Network New alternative to DSL/Cable modems IEEE 802.16 Progress Work on 802.16 started in July 1999. Four years into its mission, the IEEE 802.16 Working Group on Broadband Wireless Access has delivered a base and three follow-on standards. IEEE 802.16 (“Air Interface for Fixed Broadband Wireless Access Systems”) was approved in December 2001. This standard is for wireless MANs operating at frequencies between 10 and 66 GHz. IEEE 802.16.2, published in 2001, specifies a “recommended practice” to address the operation of multiple, different broadband systems in the 10-66 GHz frequency range. In January of this year, the IEEE approved an amendment to 802.16, called 802.16a, which adds to the original standard operation in licensed and unlicensed frequency bands from 2-11 GHz. 802.16c, which was approved in December 2002, is aimed at improving interoperability by specifying system profiles in the 10-66 GHz range. WiFi

802.11/802.16 WiFi

WiFi

WiFi

WiFi

What is WIMAX ? WiMAX is an IP based, wireless broadband access technology that provides performance similar to 802.11/Wi-Fi networks with the coverage and QOS (quality of service) of cellular networks. WiMAX is also an acronym meaning "Worldwide Interoperability for Microwave Access (WiMAX).

What is WIMAX ? WiMAX (Worldwide Interoperability for Microwave Access) is a telecommunications protocol that provides fixed and mobile Internet access. The current WiMAX revision provides up to 40 Mbit/s with the IEEE 802.16m update expected to offer up to 1 Gbit/s fixed speeds.

What is WIMAX ? The name "WiMAX" was created by the WiMAX Forum, which was formed in June 2001 to promote conformity and interoperability of the standard. The forum describes WiMAX as "a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL".

What is last mile operation ? The "last mile" or "last kilometer" is the final leg of delivering connectivity from a communications provider to a customer. The phrase is therefore often used by the telecommunications and cable television industries. The actual distance of this leg may be considerably more than a mile, especially in rural areas.

What is last mile operation ? It is typically seen as an expensive challenge because "fanning out" wires and cables is a considerable physical undertaking. Because the last mile of a network to the user is also the first mile from the user to the world, the term "first mile" is sometimes used.

Last mile To solve the problem of providing enhanced services over the last mile, some firms have been mixing networks for decades. One example is Fixed Wireless Access, where a wireless network is used instead of wires to connect a stationary terminal to the wireline network.

What is Wimax ? WiMAX is a wireless digital communications system, also known as IEEE 802.16, that is intended for wireless "metropolitan area networks". WiMAX can provide broadband wireless access (BWA) up to 30 miles (50 km) for fixed stations, and 3 - 10 miles (5 - 15 km) for mobile stations. In contrast, the WiFi/802.11 wireless local area network standard is limited in most cases to only 100 - 300 feet (30 - 100m).

Integration with an IP-based network

Integration with an IP-based network The WiMAX Forum has proposed an architecture that defines how a WiMAX network can be connected with an IP based core network, which is typically chosen by operators that serve as Internet Service Providers (ISP); Nevertheless the WiMAX BS provide seamless integration capabilities with other types of architectures as with packet switched Mobile Networks.

Integration with an IP-based network The WiMAX forum proposal defines a number of components, plus some of the interconnections (or reference points) between these, labeled R1 to R5 and R8: SS/MS: the Subscriber Station/Mobile Station ASN: the Access Service Network[19] BS: Base station, part of the ASN ASN-GW: the ASN Gateway, part of the ASN CSN: the Connectivity Service Network HA: Home Agent, part of the CSN AAA: Authentication, Authorization and Accounting Server, part of the CSN NAP: a Network Access Provider NSP: a Network Service Provider

Integration with an IP-based network It is important to note that the functional architecture can be designed into various hardware configurations rather than fixed configurations. For example, the architecture is flexible enough to allow remote/mobile stations of varying scale and functionality and Base Stations of varying size - e.g. femto, pico, and mini BS as well as macros.

WiMAX installation There are numerous devices on the market that provide connectivity to a WiMAX network. These are known as the "subscriber unit" (SU). There is an increasing focus on portable units. This includes handsets (similar to cellular smartphones); PC peripherals (PC Cards or USB dongles); and embedded devices in laptops, which are now available for Wi-Fi services.

WiMAX installation In addition, there is much emphasis by operators on consumer electronics devices such as Gaming consoles, MP3 players and similar devices. It is notable that WiMAX is more similar to Wi-Fi than to 3G cellular technologies.

WiMAX installation The WiMAX Forum website provides a list of certified devices. However, this is not a complete list of devices available as certified modules are embedded into laptops, MIDs (Mobile Internet devices), and other private labeled devices.

WiMAX installation: Gateways WiMAX gateway devices are available as both indoor and outdoor versions from several manufacturers. Many of the WiMAX gateways that are offered by manufactures such as Airspan, ZyXEL, Huawei, Motorola, and Greenpacket are stand-alone self-install indoor units. Such devices typically sit near the customer's window with the best WiMAX signal, and provide:

WiMAX installation: Gateways An integrated Wi-Fi access point to provide the WiMAX Internet connectivity to multiple devices throughout the home or business. Ethernet ports should you wish to connect directly to your computer or DVR instead. One or two PSTN telephone jacks to connect your land-line phone and take advantage of VoIP.

WiMAX installation: Gateways Indoor gateways are convenient, but radio losses mean that the subscriber may need to be significantly closer to the WiMAX base station than with professionally-installed external units. Outdoor units are roughly the size of a laptop PC, and their installation is comparable to the installation of a residential satellite dish. A higher-gain directional outdoor unit will generally result in greatly increased range and throughput but with the obvious loss of practical mobility of the unit.

WiMAX installation: Dongles There are a variety of USB dongles on the market which provide connectivity to a WiMAX network. Generally these devices are connected to a notebook or netbook whilst on the go. Dongles typically have omnidirectional antennae which are of lower-gain compared to other devices, as such these devices are best used in areas of good coverage.

WiMAX installation: Mobile phones HTC announced the first WiMAX enabled mobile phone, the Max 4G, on Nov 12th 2008.[12] The device was only available to certain markets in Russia on the Yota network.

WiMAX installation: Mobile phones HTC and Sprint Nextel released the second WiMAX enabled mobile phone, the EVO 4G, March 23, 2010 at the CTIA conference in Las Vegas. The device, made available on June 4, 2010,[13] is capable of both EV-DO(3G) and WiMAX(4G) as well as simultaneous data & voice sessions. The device also has a front-facing camera enabling the use of video conversations.[14] A number of WiMAX Mobiles are expected to hit the US market in 2011.

WiMAX installation: MAC (data link) layer The WiMAX MAC uses a scheduling algorithm for which the subscriber station needs to compete only once for initial entry into the network. After network entry is allowed, the subscriber station is allocated an access slot by the base station. The time slot can enlarge and contract, but remains assigned to the subscriber station, which means that other subscribers cannot use it.

WiMAX installation: MAC (data link) layer In addition to being stable under overload and over-subscription, the scheduling algorithm can also be more bandwidth efficient. The scheduling algorithm also allows the base station to control Quality of service (QoS) parameters by balancing the time-slot assignments among the application needs of the subscriber station.

WiMAX Performance As a standard intended to satisfy needs of next-generation data networks (4G), WiMAX is distinguished by its dynamic burst algorithm modulation adaptive to the physical environment the RF signal travels through. Modulation is chosen to be more spectrally efficient (more bits per OFDM/SOFDMA symbol).

WiMAX Performance That is, when the bursts have a high signal strength and a high carrier to noise plus interference ratio (CINR), they can be more easily decoded using digital signal processing (DSP).

WiMAX Performance In contrast, operating in less favorable environments for RF communication, the system automatically steps down to a more robust mode (burst profile) which means fewer bits per OFDM/SOFDMA symbol; with the advantage that power per bit is higher and therefore simpler accurate signal processing can be performed.

WiMAX vs. LTE The more recent Long Term Evolution (LTE) standard is a similar term describing a parallel technology to WiMAX that is being developed by vendors and carriers as a counterpoint to WiMAX.

An example of Wireless competition Korea launched Wimax at 2nd quarter of 2006 and then launched HSPA one quarter after launched Wimax. At the end of 2008 there were 8.4 million HSPA subscribers and 350,000 Wimax subscribers in Korea. Almost all of HSPA subscribers come from 2G and 3G users who have been tempted to upgrade to new devices by high subsidies, whereas Wimax subscribers almost all are newcomers.

An example of wireless competition Deployment of Wimax is still limited (spotted), whereas there are well over 100 countries where HSPA networks are deployed, and even where there is no HSPA coverage there is backward compatibility (using HSPA devices) to pre-existing networks (GSM and WCDMA) with a roaming infrastructure already in place

WiMAX statistics As of October 2010, the WiMAX Forum claims there are over 592 WiMAX (fixed and mobile) networks deployed in over 148 countries. Yota is the largest WiMAX network operator in the world, but has announced that it will move new network deployments to LTE and, subsequently, change its existing networks as well.

What is HSPA ? High Speed Packet Access (HSPA) is an amalgamation of two mobile telephony protocols, High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA), that extends and improves the performance of existing WCDMA protocols. A further standard, Evolved HSPA (also known as HSPA+), was released late in 2008 with subsequent adoption worldwide beginning in 2010.

WiMAX competitors Within the marketplace, WiMAX's main competition comes from existing, widely deployed wireless systems such as UMTS, CDMA2000, existing Wi-Fi and mesh networking.

WiMAX competitors Speed vs. Mobility of wireless systems: Wi-Fi, HSPA, UMTS, GSM

The future of wireless networks In the future, competition will be from the evolution of the major cellular standards to so-called 4G, high-bandwidth, low-latency, all-IP networks with voice services built on top. The worldwide move to 4G for GSM/UMTS and AMPS/TIA (including CDMA2000) is the 3GPP Long Term Evolution effort.