Developing an Effective Wireless Middleware Strategy

Mobility Mobility is “the ability to move freely” Wireless access to enterprises presents many challenges: –bandwidth –device issues –synchronization of data Middleware needed to address the challenges

Wireless Access Challenges Bandwidth –The pervasive devices are still mobile phones –2.5/3G roll-out has been slow –Networks are unreliable Wi-Fi Solution –802.11b provides hot spots (range of 300 feet) –High-speed (>= 11 Mbps) –Access to wired network backbone

Wireless Access Challenges Device Issues –Thin client Limited display, text only in some cases Battery life, memory very limited Open programming environments limited –Thick client PDA’s support 256 color displays Improved battery life, CPU and memory Standard operating systems Mic and speaker access

Wireless Access Challenges Synchronizing Data –Replication model Hot-sync of data to docking station Static applications Lowers user acceptance –Real-time access Requires reliable network connectivity Allows heavy lifting to be done in-network Increases user acceptance

Extend the Web Use existing web infrastructure From wireless device to the applications requires middleware Why isn’t connectivity to web applications enough? –User devices too difficult to enter data with –Limited display and stylus difficult

Middleware Architecture

Middleware to Effectively Add Speech Speech can greatly improve the user experience Press to talk – user speaks input to the device Audio cue – prompts can be used for tutorial, accessibility, etc. The middleware needs to allow access to the speech resources in a web-centric way

Speech Recognition Input –Speech from user –Grammar or dictionary of expected words/phrases Processing –Phonetic classification using acoustic models –Pattern matching with grammar Output –Recognition matches and confidence

Speech Synthesis Input –Text/ASCII or XML markup (SSML) –Language models Processing –Phonetic concatenation of audio Output –Audio representation of text

Speech Ecosystem Built from IVR –Speech has emerged as an extension of IVR touchtone Hardware-Centric –Telephony switch and board vendors have added speech technologies Wireless Access – Data devices such as PDA’s are NOT connecting over a voice channel!

Web Architecture for Speech Host-based Technologies –The Speech Recognition and Speech Synthesis resources are software-based. –Can be deployed alongside web infrastructure Transactional Speech –Client/server interaction for speech resources –Each transaction defined as a Web Service –Allow the developer to add speech where appropriate

Role of the Middleware Resource Management –Speech Resources deployed on off-the-shelf hardware –Requires a common session, media and control protocol Open Standards –Session Initiation Protocol (SIP, RFC 3261) –Real-time Transport Protocol (RTP, RFC 1889) –Speech Server Control (SPEECSC, IETF WG)

Session Control SIP –Modeled after HTTP and SMTP –Provides client/server network programming model –Transported via UDP –REGISTER message allows resources dynamic binding –Includes Proxy functionality for load balancing

Media Transport RTP –Currently using in streaming video/audio web applications –Allows consumer/producers of audio to be connected via a network –Transported via UDP –Real-time packets to reduce latency and impact of lost packets –Quality of service must be managed

Resource Control SPEECSC –Working group chartered after initial MRCP Internet drafts submitted –Defines message set to control Speech Recognizers Speech Synthesizers Streaming Prompt Server –Currently HTTP-style –Web services being investigated

Component Servers for Speech Define each resource as a Component Server –Resources acquired thru SIP –Media transmitted/received thru RTP –Control thru MRCP load grammar queue TTS play perform recognition –Common resources pooled for resource management

Media Session Framework (MSF) MSF server ASR Engine TTS Engine Prompt Cache UAS RTP ASR client UAC UAC = SIP User Agent Client UAS = SIP User Agent Server SIP messaging RTP media Media Source/Target Prompt client TTS client UAC

Device Access to the Component Servers Devices must be able to use the resources in a standards-based way

Conclusion Bandwidth for wireless networks is improving Middleware needs to address: –resource management –load balancing –media resource integration Open standards-based approach

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