1、 Recommendation ITU-R S.1897(01/2012)Cross-layer QoS provisioning in IP-based hybrid satellite-terrestrial networksS SeriesFixed-satellite servicesii Rec. ITU-R S.1897 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economical use of the radio-f
2、requency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Radiocommunication Sector are performed by World and Regional Radio
3、communication Conferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of Resolution ITU-R 1. Forms to be used for the submission of
4、patent statements and licensing declarations by patent holders are available from http:/www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent information database can also be found. Series of ITU-R Recommendat
5、ions (Also available online at http:/www.itu.int/publ/R-REC/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television) F Fixed service M Mobile, radiodetermination, amateur and re
6、lated satellite services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service systems SM Spectrum management SNG Satellite news gathering TF
7、 Time signals and frequency standards emissions V Vocabulary and related subjects Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2012 ITU 2012 All rights reserved. No part of this publication may be reproduce
8、d, by any means whatsoever, without written permission of ITU. Rec. ITU-R S.1897 1 RECOMMENDATION ITU-R S.1897 Cross-layer QoS provisioning in IP-based hybrid satellite-terrestrial networks (2011) Scope This Recommendation provides guidelines about implementing cross-layer design approaches for impr
9、oving the performance of multimedia applications over satellite networks (either stand-alone or hybrid). The ITU Radiocommunication Assembly, considering a) that satellite systems are increasingly being used for providing broadband applications directly to users in addition to their role as backbone
10、 links; b) that fading events ultimately impact the application layer of services provided by such satellite systems; c) that cross-layer design consists in allowing interactions and sharing state variables among different protocol layers (including non-adjacent ones) in order to achieve network cap
11、acity and performance gain; d) that a cross-layer approach conceived to achieve a better adaptation to the satellite transmission dynamics has the potential to mitigate the effect of fading events; e) that cross-layer approaches may also be used to adapt the transmission requirements in case of an e
12、vent affecting the available bandwidth; f) that the overall performance of a satellite link may be affected by a variety of factors (delays, delay variations, throughput, etc.) that can be monitored through a cross-layer approach, noting a) that Recommendation ITU-R S.1711 provides guidelines to imp
13、lement a number of transmission control protocol (TCP) performance enhancements over IP-based satellite networks; b) that various cross-layer applications have been studied and experimented (see Report ITU-R S.2222), recommends 1 that a cross-layer design approach should be used for satellite networ
14、ks (either stand-alone or hybrid); 2 that the reference architectures, set out in Annex 1 of this Recommendation, should be considered as a basis when implementing cross-layer design approaches; 3 that, when assessing the impact of fading events into different layers, Annex 2 should be considered; 4
15、 that cross-layer design approaches in satellite links employing TCP should be considered in assessing the throughput and delay performance (see Annex 3). NOTE Report ITU-R S.2222 provides background material on cross-layer design concepts and methodologies. 2 Rec. ITU-R S.1897 TABLE OF CONTENTS Pag
16、e Annex 1 Reference architectures for implementing cross-layer design approaches 6 1 Scope 6 2 Reference architectures. 6 2.1 Hybrid satellite-WiFi network architecture 7 2.2 Hybrid satellite-WiMAX network architecture 8 2.2.1 Hybrid satellite-WiMAX network protocol architecture . 9 Annex 2 Cross-La
17、yer based QoS performance of hybrid satellite-terrestrial networks . 11 1 Scope 11 2 Rain fade mitigation and cross-layer QoS design 11 3 Fading effects on QoS for satellite-WiFi multimedia networks . 11 3.1 Simulation network model 11 3.2 Bandwidth On Demand (BOD) scheme used in OPNET simulations .
18、 12 3.2.1 Return channel bandwidth allocation algorithm 12 3.3 Simulation experiments and performance results Scenario 1 14 3.3.1 Simulation model . 14 3.3.2 Simulation experiment results 15 3.3.3 Summary 21 3.4 Simulation experiments and performance results Scenario 2 21 3.4.1 Simulation network mo
19、del . 21 3.4.2 QoS provisioning . 22 3.4.3 Traffic model 22 3.4.4 Satellite link loading 22 3.4.5 Simulation parameters 22 3.4.6 Simulation experiments results 24 3.4.7 Summary 32 4 Cross-layer based QoS for VoIP in hybrid satellite-WiMAX networks 32 4.1 Introduction . 32 4.2 Cross-layer VoIP rate a
20、daptation 32 Rec. ITU-R S.1897 3 Page 4.2.1 RTCP driven approach . 32 4.2.2 Adaptive multirate wideband (AMR-WB) approach . 33 4.3 Satellite-WiMAX performance model . 34 4.3.1 Delay model . 34 4.4 Performance results 35 4.4.1 Satellite subnetwork: Aggregate rate adaptation 35 4.4.2 Terrestrial subne
21、twork performance 37 4.5 Summary . 38 Annex 3 Cross-layer design for satellite link using TCP as transport protocol 38 1 Scope 38 2 Introduction 38 3 Reference network architecture 39 3.1 Simulation parameters 40 3.2 Assumptions . 40 4 Performance results 41 5 Summary . 43 6 Conclusions 43 4 Rec. IT
22、U-R S.1897 List of acronyms 3G Third generation 4G Fourth generation AAL ATM adaptation layer ACELP Algebraic code excitation linear prediction ACK Acknowledgment ACM Adaptive coding and modulation AMR-WB Adaptive multirate wideband APP Application ARQ Automotive repeat request ASN Access service ne
23、twork ATM Asynchronous transfer mode AWGN Additive white Gaussian noise BDP Bandwidth delay product BIC Binary increase congestion control BOD Bandwidth on demand BPSK Binary phase-shift keying CCM Constant coding and modulation CMR Code model request CQI Channel quality information CRA Continuous-r
24、ate assignment C-TCP Compound TCP DAMA Demand assignment multiple access DLSR Delay since last sender report DVB Digital video broadcast DVB-RCS Digital video broadcast return channel by satellite DVB-S Digital video broadcast by satellite DVB-S2 Digital video broadcast satellite transmission 2ndgen
25、eration EF Expedited forward ETH Ethernet ETSI European Telecommunications Standards Institute FEC Forward error correction FSS Fixed satellite service FTP File transfer protocol GEO Geostationary earth orbit GSM Global system for mobile communications Rec. ITU-R S.1897 5 GSM-AMR GSM adaptive multi-
26、rate GSM-EFR GSM enhanced full rate GT Gateway terminal GW Gateway HTTP Hypertext transfer protocol IEEE Institute of Electrical and Electronics Engineers IP Internet protocol ISO International Organization for Standardization ITU-R SG ITU-R Study Group ITU-R WP ITU-R Working Party LAN Local area ne
27、twork LOS Line of sight MAC Medium access control MAC-CPS MAC common part sublayer MAC-CS MAC convergence sublayer MF-TDMA Multiple-frequency time-division multiple access MIMD Multiplicative increase multiplicative decrease MODCOD Modulation and coding MPEG Moving picture experts group NCC Network
28、control center OFDM Orthogonal frequency division multiplexing OSI Open system interconnect PDU Packet data unit PER Packet error rate PHY Physical layer PSK Phase shift keying QoS Quality of service QPSK Quadrature phase-shift keying RCS Return channel satellite RCST Return channel satellite termin
29、al RR Receiver report RRA Radio resource allocation RRM Radio resource management RT Real time RTCP Real time transport control protocol RTO Retransmission on time out 6 Rec. ITU-R S.1897 RTT Roundtrip time SACK Selective acknowledgement SNIR Signal to noise interference ratio SR Sender report S-TCP
30、 Scalable TCP TCP Transmission control protocol TDM Time division multiplexing TDMA Time division multiple access TLSR Time of last sender report ToS Type of service TV Television UDP User datagram protocol UE User equipment VCM Variable coding and modulation VoIP Voice over Internet protocol VR-JT
31、Variable rate real time traffic jitter tolerant VR-RT Variable rate real time traffic WiFi Wireless fidelity (products based on IEEE 802.11 standards) WiMAX Worldwide interoperability for microwave access Annex 1 Reference architectures for implementing cross-layer design approaches 1 Scope This Ann
32、ex presents reference architectures for hybrid satellite wireless networks including satellite links and either a WiFi or WiMAX terrestrial segment. This will be followed by a description of quality of service (QoS) improvement in multimedia networks using cross-layer design approaches. 2 Reference
33、architectures Figure 1 shows a hybrid satellite-wireless network operating at Ka-band to support multimedia applications. Various scenarios could include a Geostationary Earth Orbit (GEO) satellite system with digital video broadcast (DVB-S2/return channel satellite (RCS) air interface connected wit
34、h either a WiFi and/or a WiMAX terrestrial segment. As shown in this figure, DVB-RCS terminals (RCSTs) could also directly support applications such as VoIP, streaming multimedia, video conferencing, and bulk data transfer. The system is composed of gateway terminals (GTs), RCSTs Rec. ITU-R S.1897 7
35、 and network control and management center. The forward link, i.e., from the gateway to the user terminal (solid blue arrows) follows DVB-S2 with adaptive coding and modulation (ACM). The return link from the terminal to gateways (dashed red arrows) is based on DVB-RCS. FIGURE 1 DVB-S2/RCS and WiFi/
36、WiMAX network S.1897-01WiMAXRCST2RCST1WAPInternetHUB BTDVB-S2: Satellite Transmission 2nd Generation DVB-RCS: DVB Return Channel by Satellite WAP: Wireless Access PointRCST: Return Channel Satellite Terminal The DVB-S2 features two main enhancements compared with its predecessor, DVB-S. First, it in
37、troduces an improved physical layer, offering several higher order modulation waveforms with more powerful forward error correction (FEC). Secondly, it supports real-time adaptation to link and propagation conditions. It supports 28 combinations of modulation format and coding schemes to guarantee a
38、 low packet error rate across a wide range of signalled noise plus interference ratio (SNIR). The three operational modes supported include (a) constant coding and modulation (CCM) (b) variable coding and modulation (VCM) and (c) adaptive coding and modulation (ACM). DVB-RCS used on the return link
39、implements multi-frequency time-division multiple access (MF-TDMA) and adaptive coding. The return link MF-TDMA enables it to have bi-dimensional framing in which every time-frequency window is portioned into carriers, super frames, frames and slots. The MF-TDMA return link is coded with concatenate
40、d Convolution and Reed Solomon codes. The data may be encapsulated in Asynchronous Transfer Mode (ATM) cells using ATM Adaptation layer 5 or it may use native IP encapsulation over MPEG-2. These protocols allow IP traffic transmission over the physical layer which is used in simulation experiments.
41、Rain becomes the most affecting atmospheric event for transmission in the Ka-band. Therefore, the effect of fading on various MAC and application layer parameters using cross-layer design approach must be evaluated. The differentiated services (DiffServ) model is assumed to prioritize IP-based netwo
42、rks interfacing with WiFi and WIMAX segments. 2.1 Hybrid satellite-WiFi network architecture To provide broadband connectivity to areas of both low population density network (i.e. rural areas) and high population density (i.e., suburban and urban areas), hybrid networks are composed of both satelli
43、te and terrestrial radio access technologies. 8 Rec. ITU-R S.1897 FIGURE 2 Satellite Wireless network protocol architecture S.1897-02APPUDP/RTCPIPMACETHHUBNCCRCSTDVB-RCSRRMGenericplattformGSM, 3G, 4GWiFiUser(802.11, GSM, .)IPMACETHIPIP over S2ALDVB-S2PHYAAL5ATMMF-QPSKIPIP over S2ALDVB-S2PHYAAL5ATMMF
44、-TDMAQPSKETHMACETHMACIP IPGeneric PHYGeneric MACGeneric PHYGeneric MACIPUDP/RTCPAPPFigure 2 shows the satellite-terrestrial wireless network protocol architecture. The wireless segment can use protocols such as GSM, 3G, WiFi, WiMAX, and 4G. Both the satellite segment and the terrestrial network will
45、 provide resource allocation algorithms and a control management system. Other components in the network architecture include the access service network gateway, and the DVB-RCS Radio Resource Management (RRM). The RRM of the satellite terminal checks if enough resources are available to enable admi
46、ssion of new user equipment requesting services from the gateway to the satellite link. The RCST communicates with the Hub, which is associated to a network control center (NCC). The NCC controls the interactive network, user service request via satellite access and manages the satellite spectrum de
47、pending on the satellite terminals requests. 2.2 Hybrid satellite-WiMAX network architecture Figure 3 shows hybrid satellite network using DVB-S2/RCS terminals connected with a WiMAX network. Rec. ITU-R S.1897 9 FIGURE 3 Hybrid DVB-S2/RCS satellite-WiMAX network WiMAXstationSatelliteRCST NRCST 2RCST
48、 1HUBNCCInternet2.2.1 Hybrid satellite-WiMAX network protocol architecture Figure 4 shows the hybrid satellite-WiMAX network protocol architecture. The terrestrial link is based on IEEE 802.16, where a user in the core network directs traffic (e.g. VoIP conversation) to a mobile user, called User Eq
49、uipment (UE). The UE is placed in an area serviced by the WiMAX network. The Base Station (BS) is responsible of the IEEE 802.16 connectivity through the radio link to the UE located inside its coverage area. An adaptive physical layer maximizes the data rate by adjusting transmission modes to channel variations while maintaining a prescribed Packet Error Rate (PER). The WiMAX Radio Resource Management (RRM) is in charge of utilizing the limited radio spectrum resources and radio network infrastructure of its associated BS efficiently
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