tailieunhanh - Resource Management in Satellite Networks part 17

Resource Management in Satellite Networks part 17. This book provides significant knowledge on innovative radio resource management schemes for satellite communication systems that exploit lower layer adaptivity and the knowledge of layer 3 IP QoS support and transport layer behavior. The book integrates competencies considering all the parts of system design: propagation aspects, radio resource management, access protocols, network protocols, transport layer protocols, and more, to cover both broadband and mobile satellite systems | 142 Giovanni Giambene Cristina Parraga Niebla Victor Y. H. Kueh CQI value Modulation and coding Number of codes used per TTI Bits per TTI transport block size 1 QPSK 1 3 on each code 960 bits are sent in a TTI 1 137 2 1 173 3 1 233 4 1 317 5 1 377 6 1 461 7 2 650 8 2 792 9 2 931 10 3 1262 11 3 1483 12 3 1742 13 4 2279 14 4 2583 15 5 3319 16 16QAM 1 3 on each code 1920 bits are sent in a TTI 5 3565 17 5 4189 18 5 4664 19 5 5287 20 5 5887 21 5 6554 22 5 7168 23 7 9719 24 8 11418 25 10 14411 26 12 17237 27 15 21754 28 15 23370 29 15 24222 30 15 25558 Table Example of CQI mapping in transport block size for TTI 2 ms terrestrial standard the highlighted CQIs are those considered for simulations referring to a GOOD BAD channel model. executed on board or not. In the case of a bent-pipe satellite all medium access control mechanisms must be located at the Gateway station or the network control center. In any case the large distances involved in a satellite system disable the HSDPA capabilities of fast retransmissions and quick adaptation to physical channel variations thus scaling the performance that link adaptation mechanisms can achieve. In GEO satellite systems retransmissions take too long time. Therefore FER upper bounds should be adequately much lower in order to reduce Chapter 5 ACCESS SCHEMES AND PACKET SCHEDULING TECH. 143 statistically the number of required packet retransmissions. Furthermore the behavior of the channel is not comparable to the terrestrial mobile channel deeper and longer fades are expected in the satellite case in contrast to the fast fades of the terrestrial mobile channel. All the issues discussed above condition the performance of the packet scheduler which is the main entity of the HSDPA concept. With the purpose of testing the performance of different scheduling techniques in a simplified satellite-HSDPA scenario the following assumptions have been made A multi-beam GEO bent-pipe satellite has been considered. All Radio Access .