Ka Band and Broadband Satellite service

Transcription

1 Ka Band and Broadband Satellite service

2 Agenda Advantage & Necessity of Ka-band Attenuation Mitigation Techniques Current Broadband Satellite service

3 ADVANTAGE & NECESSITY OF KA-BAND

4 Why Ka Band Ka-band spectrum is relatively abundant and therefore attractive for services that cannot find room at the lower frequencies. There is 2 GHz of uplink and downlink spectrum available on a worldwide basis. Conversely, with enough downlink EIRP, smaller antennas will still be compatible with 2 spacing. Another facet of Ka-band is that small spot beams can be generated onboard the satellite with achievable antenna apertures. Is Ka band the future of Satellite Communication?

5 Regions and areas

6 ITU Frequency Allocations for FSS Region 1 DOWNLINK: GHz UPLINK: GHz Region 2 DOWNLINK: GHz UPLINK: GHz Region 3 DOWNLINK: GHz UPLINK: GHz

7 Advantages of Ka-band Less congestion compare to C and Ku band in this region Wide bandwidth available (3.5 GHz uplink and downlink)

8 ATTENUATION MITIGATION TECHNIQUES

9 Ka Band System Design Consideration The biggest being the much greater attenuation for a given amount of rainfall (nominally by a factor of three to four, in decibel terms, for the same availability, of Ku-Band). This can, of course, be overcome by increasing the transmitted power or receiver sensitivity (e.g., antenna diameter) to gain link margin. Some other techniques that could be applied in addition to or in place of these include: (1)ACM -Reducing the data rate, Mod, Code during rainfall, (2) UPC -Dynamic power control on the uplink and downlink, (3) Hybrid Transponder -Transferring the transmission to a lower frequency such as Ka/Ku, Ka/C Band (4) Diversity -Using multiple-site diversity to sidestep heavy rain-cells.

10 Key Techniques RF Part MODEM Part 1. Uplink Power Control (UPC) 3. Advanced modulations with lower threshold 4. Adaptive Code and Modulation (ACM) 2. Diverse Site Switching (DSS) 5. Dynamic Capacity Allocation (DCA)

11 1. Uplink Power Control (UPC) UPC is to reduce the effect of uplink rain attenuation. Usually this will be used for the GWs which have plenty of HPA power margin. The system reserves some HPA power as UPC margin in clear sky operation. In rain condition, the UPC margin will be used to compensate the rain. User terminal could also have UPC margin. However, this might not be the case due to limitation of BUC power.

12 1. UPC function Usually this will be used for the GWs which have plenty of HPA power margin. The system reserves some HPA power as UPC margin in clear sky operation. Power uplink (db) Uplink power increase from UPC RainFade UPC Gain Rain Fade beacon (db) Beacon signal drop due to rain fade Time (Minutes)

13 2. Diverse Site Switching (DSS) Main Site The Diverse Site Switching (DSS) feature allows seamless switching between the main & diversityrf sites during heavy rainfall on the gateway sites Fibre optic Diversity Site All User Terminals are automatically switched without losing connections Without DSS function, average outage during heavy rainfall ~ mins The DSS feature is now commercially operational & is able to simultaneously switch > 40K concurrent users

14 Diversity Site Switching Diversity Site Switching Percentage of time for two sites, P2 Beyond the UPC limitation All traffic carriers switch to diversity site From ITU-R, The increasing in availability by site-diversity is a function of distance between two GW stations. Percentage of time for single site (99.5%) will be increased if two sites are applied (99.9%) at 50km separation or at 99.9% link availability at BKK at 30GHz, 40km separation, site diversity could reduce rain attenuation from 43dB to 22 db Percentage of time for single site, P1

15 2. Diverse Site Switching (DSS) (cont.) Switchover to Diversity Site Switch back to main site Diversity Site Beacon Signal Predefined Threshold Main Site Beacon Signal

16 3. Advanced Coding Technology Effective error correction coding requires less power to detect signal in noisy environment The minimum requirement is about 0 1 db Effective time adjustment (ACM) to overcome rain dept requires less margin The required margin is about 1-2 db

17 4. Adaptive Code and Modulation (ACM) More effective modulation and coding Typical Modem QPSK&8PSK with RS coding C/N required (db) ipstar Modem Higher bit efficiency is limited ipstar bit efficiency advantage at a given power Effective Bit Efficiency (bps/hz) ipstar can extend to higher bit efficiency ipstar power advantage at a given bit efficiency

18 4. Adaptive Code and Modulation (ACM) ACM is the algorithm to adjusts modulation and coding on the fly on a per user basis to improve throughput and link availability. During clear sky, system will utilize the highest modulation and FEC Code rate obtainable Result in higher bit rate with less link margin, or less power at clear sky During rain, modulation and FEC Code rate can dynamically change to maintain link availability Change of modulation and FEC may result a lower capacity momentarily for a particular area 19 Mar

19 4. Adaptive Code and Modulation (cont.) Result-ACM -Higher bit rate with less link margin; less power -Highly reliable service even in rain environment.

20 3. Dynamic link Allocation (DLA) (cont.)

21 3. Dynamic link Allocation (DLA) (cont.) 8PAH PAH QPSK QPSK QPSK QPSK 0.325

22 5. Dynamic Capacity Allocation (DCA) An assignment of radio resources (channel and time slots) to each user terminal based on its capacity (kbps) requirement (class of Service (CoS)) This assignment assigned by IPSTAR Gateway.

23 5. Dynamic Capacity Allocation (DCA) Addition of ACM, DCA could assign UT in big channel in clear sky and move to smaller channel in rain condtion to maintain the link availability at rain condition. 4ch. 4ch. 2ch. 2ch. 1ch. 1ch. Clr sky Rain Fade

24 The Ultimate Bandwidth Improvement

25 IPSTAR Ground System: Summary ipstar can achieve Proprietary modulation/coding : approx. 2-3 db advantage Dynamic coding/modulation/power allocation : 2-4 db advantage Rain Margin in normal Ku-band link without dynamic resource allocation is approximately 4-6 db, depending on rain zone With dynamic resource allocation, only 1-2 db Rain Margin is required TOTAL ADVANTAGE : 4-6 db in term of power requirement (i.e times less) Intelligently allocates capacity of DCA could reserve the gateway resource.

26 IPSTAR Ground System: Summary Comparing to Typical Satellite Platform At clear sky, ipstar can provide higher bit rate At normal rain condition, ipstar also can provide higher bit rate At heavy rain, ipstar can still maintain the link availability when the typical platform has already gone Implement of TCP-A could increase throughput via satellite

27 3 CURRENT BROADBAND SATELLITE SERVICE

28 Example of current BB Service Refer the actual usage of Broadband satellite, which Thaicom4,ipstar, deploy in various country 1.Rural Communication 2.Attenuation Mitigation Techniques 3.Current Broadband Satellite service

29 RURAL COMMUNICATION- THAILAND/ MYANMAR

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31 Rural Telephone in Myanmar

32 VSAT NETWORK- VIETNAM

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35 WIFI DEMO THAILAND

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37 CELLULAR NETWORK JAPAN,THAILAND

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39 DISASTER COMMUNICATION THAILAND, CHINA, JAPAN

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45 THANK YOU