1 QoS over Demand-assigned TDMA Satellite Network Presenter: Mr Pang Yoke Kum

2 Project Participants 1. Temasek Polytechnic Mr SRINIVASAN SUKUMAR Mr PANG YOKE KUM Mr TEDDY RUSMIN Mr LOH YEOW MENG 2. Nanyang Technological University Assoc Prof. K R SUBRAMANIAM 3. Laboratories for Information Technology DR CHENG HENG SENG Project funded by SINGAREN

3 DA-TDMA - Introduction Why DA-TDMA satellite network? To efficiently allocate satellite bandwidth to remote VSATs on demend. - Every remote VSAT transmits its carrier burst at the same bandwidth and same frequency, but not at the same time. - Every remote VSAT is not pre-assigned to transmit its carrier burst within a specific time slot. - Each remote VSAT is allocated a fixed percentage of satellite bandwidth (time slots). - There is a certain percentage of satellite bandwidth which can be dynamically allocated to remote VSATs basing on users’ demands.

4 DA-TDMA - Issues - Time delay related issue - When dynamically assigned satellite bandwidth to remote VSATs, it imposes a certain amount of delay. (Eg. Time delay during the change of modem parameters). Such delay has an impact of the QoS on various applications. - Channel error related issue - With same transmit power, an change of satellite bandwidth allocation causes a change of BER at the receiving VSATs. Such change of BER has an impact of the Qos on various applications.

5 Project Objectives To contribute to the study of DA-TDMA based satellite networks in terms of providing research findings to the research community in this field of study on :- (a) the effectiveness of QoS over the DA-TDMA satellite networks and (b) the impact of channel errors over the DA-TDMA satellite networks

6 Introduction to a Star Shape DA-TDMA Satellite Network

7 Network Characteristics 1. TDM outbound 2. TDMA inbound 3. Bandwidth on Demand

8 Main Considerations In Implementing a DA-TDMA Satellite Network 1) Satellite bandwidth required. 2) Choice of satellite modem. 3) Ensuring a sufficient energy-per-bit-to-noise density ratio (Eb/No). 4) Internet Protocol. (IPv4 and IPv6)

9 Locations of VSAT Earth Station 1) Temasek Polytechnic, Singapore 2) Nanyang Technological University, Singapore 3) University of Science Malaysia, Malaysia 4) University Putra Malaysia, Malaysia

10 Proposed Star Shape DA-TDMA Satellite Network

11 Infrastructure Setup (ODU) RFT Radio Frequency Transceiver

12 Infrastructure Setup (ODU) SSPA Solid State Power Amplifier

13 Infrastructure Setup (ODU) Feedhorn

14 Infrastructure Setup (ODU) 2.4m Dish

15 Infrastructure Setup (IDU) Modem/Router

16 Infrastructure Setup (IDU) Network Management System

17 Proposed Tests Impact of Bandwidth on Demand (BoD) on QoS. Impact of Satellite Propagation Delays on QoS. Performance Evaluation for IPv4 and IPv6 Networks. QoS for several applications

18 The OSI Layers Layer 7 Application 6 Presentation 5 Session 4 Transport 3 Network 2 Data Link 1 Physical

19 Test Methodology QoS at physical layer 1) Transmit RF carrier at different transmit power levels (within the permitted range) at the Hub modem and record the BER and Eb/No values at the Remote modem. 2) Plot the BER against Eb/No graph so as to determine the range of Eb/No values, to be used for the testing of the impact of channel errors over the DA-TDMA satellite networks at Layer 3 (Network Layer). Transmission media Wireless

20 Test Methodology QoS at data link layer With transmission of different data size from remote to hub at different transmission rate, measure the channel utilisation of the data link and optimise the channel allocation for different data traffic (NMS). Medium Access Control TDM (outbound) TDMA (inbound)

21 Test Methodology QoS at network layer Tests under IPv4 and IPv6 platforms will be performed. Only the necessary routes are added to the routing table. Protocol IPv4 IPv6

22 Test Methodology QoS at transport layer For best performance, the buffer sizes on routers and switches have to be adjusted. Protocol TCP

23 Test Methodology QoS at application layer For best performance, OS window size has to be adjusted. Applications Video-conferencing Data Transfer

24 Schedule Work accomplished ODU and IDU set-up at TP Completed satellite loopback test at TP Collected BER and Eb/No data at TP Work in progress Set up modems at USM and UPM Establish satellite links with USM and UPM Setup of IPv6 network Measure network performance Video conferencing Set up Mobile IP system

25 Thank you !