Wireless Intercom

1
Wireless Intercom
Feasibility Study

• Group 09
• K.U.K.Weliwatta 040421
• J.T.C. Gunasekara 040118
• B.M.D.P. Bandara 040028
• W.A.I.M. Wickramasinghe 040422

2
Outline

• Introduction
• Basic Architecture
• Modularization
• Technical Feasibility
• Financial Feasibility
• Phases of Development
• Time Line

3
Introduction

• Wireless Intercom
• A wireless solution for traditional PABX
• Features
• Bluetooth technology as the wireless medium
• Use of VOIP techniques
• Installation on top of existing LAN
  infrastructure
• Coverage (ideal for an office environment)

4
Introduction (Cont)

• Benefits
• Free of charge voice communication
• High Quality Audio than normal Telephony
• Additional Data services
• SMS, Notifications, Alarms, Greetingsetc
• Low installation modification costs
• Lesser number of devices equipments

5
Basic Architecture
6
Modularization

• Hardware modules
• Voice Access Point
• Bluetooth module Control circuit
• Ethernet Interfacing Circuit
• Serial-Ethernet converter control circuit
• Power Supply Unit
• Software modules
• Central Server Software
• Mobile Station Software

7
Technical Feasibility

• Hardware module

8
Technical Feasibility (Cont)

• Voice Access Point
• Discovers and connects mobile devices to the
  System
• Establishes SCO full duplex voice links
• Digitize the voice channels in to UART stream.
• MUX/DEMUX multiple voice channels

Voice Access Point
Bluetooth Modules
Control Circuit
9
Technical Feasibility (Cont)

• Bluetooth Modules
• F2M03GXA
• Higher Range (500m LOS)
• Piconet and Scatternet capability
• PCM interface for 3 voice channels
• F2M03MLA
• Range (150m LOS)
• Piconet and Scatternet capability
• 16-bit Stereo codec
• Digital audio options (PCM,I2S,SPDIF)
• PCM interface for 3 voice channels

• Bluetooth Modules
• F2M03GXA
• Higher Range (500m LOS)
• Piconet and Scatternet capability
• PCM interface for 3 voice channels
• F2M03MLA
• Range (150m LOS)
• Piconet and Scatternet capability
• 16-bit Stereo codec
• Digital audio options (PCM,I2S,SPDIF)
• PCM interface for 3 voice channels

10
Technical Feasibility (Cont)

• Control Circuit
• Atmega64
• Interfacing between Bluetooth chip modules and
  Ethernet-Serial interfacing circuit
• Commands Bluetooth chips
• Service Discovery Protocol
• Establishing/Maintaining/Terminating SCO links
• Communicates with server
• Voice
• Signaling

11
Technical Feasibility (Cont)

• Ethernet Interfacing Circuit
• Transmission of audio and data signals over LAN
• PCM audio data
• Synchronous serial data
• Control data for the server
• Asynchronous serial data
• Ethernet data
• Packet based transmission
• Conversion?

12
Technical Feasibility (Cont)

• Ethernet Interfacing Circuit
• Using Microcontroller
• Programming difficulty
• Circuit Design problems eg noise
• Serial-Ethernet converter
• Standard interfaces ( RS 232/ RS 485 )
• Flexible (IP/ Port / Protocol assignment)
• Direct conversion of PCM Ethernet not possible
• PCM- PS232 conversion
• Implemented on a microcontroller

13
Technical Feasibility (Cont)

• Ethernet Interfacing Circuit

14
Technical Feasibility (Cont)

• Control circuit
• Sync-Async conversion (PCM-RS232)
• Handling multiple audio data streams
• Control data for the server
• Multiplexing
• Addressing
• IP, port, protocol assignment
• Implement In the same microcontroller
• Power Supply Unit
• 5V DC from 230V AC

15
Technical Feasibility (Cont)

• Software module
• Central Server Station
• C Programmed Central Server Software.
• Mobile Station
• Symbian C based Mobile Application
• Java application (Based on JSR 82 API)

16
Technical Feasibility (Cont)

• Central Server Station
• Functionality
• Communication Switching center
• HLR (Home Location Register)
• VLR (Visitor Location Register)
• Paging
• Access Point Management
• Challenges
• Switching Speed
• Maintaining Voice Quality
• User Detection ( Detecting Both Headset and
  phone)
• Improved Efficiency

17
Technical Feasibility (Cont)

• Mobile Station
• Functionality
• Accessing The Server
• Communication with server
• Establishing and Terminating connections
• Managing the Headset
• Challenges
• Providing User Friendly Mechanism
• Reducing ambiguousness

18
Financial Feasibility
19
Phases of Development

• Phase 01
• Voice Communication between Mobile unit and
  Bluetooth module using Development Boards and
  manufacturer Software
• Development of a Control circuit to replace
  development boards
• Phase 02
• Serial to Ethernet conversion Circuit (PCMData
  signals into TCP/IP packets)
• Phase 03
• Central Server Software development
• Phase 04
• Mobile Phone Software
• Including Additional Functionality (Optional)
• Phase 05
• Power Supply Unit
• Completion of Circuits, Packaging Housing

20
Time Line
21

• Questions?

22

• Thank You!