3GPP Broadband Evolution to IMT-Advanced - 4G Americas

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Figure 52: LTE-Advanced Relay 128Direct LinkRelay LinkAccessLinkAs demonstrated in this section, LTE-Advanced will have tremendous capability. Althoughinitial deployments of LTE will be based on Release 8, as new spectrum becomesavailable in the next decade, especially if it includes wide radio channels, then LTE-Advanced will be the ideal technology for these new bands. Even in existing bands,operators are likely to eventually upgrade their LTE networks to LTE-Advanced to obtainspectral efficiency gains and capabilities such as relaying.UMTS TDDMost WCDMA and HSDPA deployments are based on FDD, in which the operator usesdifferent radio bands for transmit and receive. An alternate approach is TDD, in whichboth transmit and receive functions alternate in time on the same radio channel. 3GPPspecifications include a TDD version of UMTS, called UMTS TDD.TDD does not provide any inherent advantage for voice functions, which need balancedlinks—namely, the same amount of capacity in both the uplink and the downlink. Manydata applications, however, are asymmetric, often with the downlink consuming morebandwidth than the uplink, especially for applications like Web browsing or multimediadownloads. A TDD radio interface can dynamically adjust the downlink-to-uplink ratioaccordingly, hence balancing both forward-link and reverse-link capacity. Note that forUMTS FDD, the higher spectral efficiency achievable in the downlink versus the uplink iscritical in addressing the asymmetrical nature of most data traffic.The UMTS TDD specification also includes the capability to use joint detection in receiversignalprocessing, which offers improved performance.One consideration, however, relates to available spectrum. Various countries around theworld including those in Europe, Asia, and the Pacific region have licensed spectrumavailable specifically for TDD systems. For this spectrum, UMTS TDD or, in the future, LTEin TDD mode is a good choice. It is also a good choice in any spectrum that does notprovide a duplex gap between forward and reverse links.In the United States, there is limited spectrum specifically allocated for TDD systems. 129UMTS TDD is not a good choice in FDD bands; it would not be able to operate effectivelyin both bands, thereby making the overall system efficiency relatively poor.128 Source: 3G Americas’ member contribution.Transition to 4G: 3GPP Broadband Evolution to IMT-Advanced, Rysavy Research/3G Americas, Aug 2010 Page 112
As discussed in more detail in the “WiMAX” section, TDD systems require networksynchronization and careful coordination between operators or guardbands, which maybe problematic in certain bands.There has been little deployment of UMTS TDD. Future TDD deployments of 3GPPtechnologies are likely to be based on LTE.TD-SCDMATD-SCDMA is one of the official 3G wireless technologies being developed, mostly fordeployment in China. Specified through 3GPP as a variant of the UMTS TDD System andoperating with a 1.28 megachips per second (Mcps) chip rate against 3.84 Mcps for UMTSTDD, the primary attribute of TD-SCDMA is that it is designed to support very highsubscriber densities. This makes it a possible alternative for wireless local loops. TD-SCDMA uses the same core network as UMTS, and it is possible for the same corenetwork to support both UMTS and TD-SCDMA radio-access networks.TD-SCDMA technology is not as mature as UMTS and CDMA2000, with 2008 being thefirst year of limited deployments in China in time for the Olympic Games. Although thereare no planned deployments in any country other than China, TD-SCDMA couldtheoretically be deployed anywhere unpaired spectrum is available—such as the bandslicensed for UMTS TDD—assuming appropriate resolution of regulatory issues.IMSIMS is a service platform that allows operators to support IP multimedia applications.Potential applications include video sharing, PoC, VoIP, streaming video, interactivegaming, and so forth. IMS by itself does not provide all these applications. Rather, itprovides a framework of application servers, subscriber databases, and gateways tomake them possible. The exact services will depend on cellular operators and theapplication developers that make these applications available to operators.The core networking protocol used within IMS is Session Initiation Protocol (SIP), whichincludes the companion Session Description Protocol (SDP) used to convey configurationinformation such as supported voice codecs. Other protocols include Real Time TransportProtocol (RTP) and Real Time Streaming Protocol (RTSP) for transporting actual sessions.The QoS mechanisms in UMTS will be an important component of some IMS applications.Although originally specified by 3GPP, numerous other organizations around the world aresupporting IMS. These include the Internet Engineering Taskforce (IETF), which specifieskey protocols such as SIP, and the Open Mobile Alliance, which specifies end-to-end,service-layer applications. Other organizations supporting IMS include the GSMA, theETSI, CableLabs, 3GPP2, The Parlay Group, the ITU, ANSI, the Telecoms and InternetConverged Services and Protocols for Advanced Networks (TISPAN), and the JavaCommunity Process (JCP).IMS is relatively independent of the radio-access network and can, and likely will, beused by other radio-access networks or wireline networks. Other applications includepicture and video sharing that occur in parallel with voice communications. Operatorslooking to roll out VoIP over networks could also use IMS. 3GPP initially introduced IMS inRelease 5 and has enhanced it in each subsequent specification release.As shown in Figure 53, IMS operates just outside the packet core.129 The 1910-1920 MHz band targeted unlicensed TDD systems, but has never been used.Transition to 4G: 3GPP Broadband Evolution to IMT-Advanced, Rysavy Research/3G Americas, Aug 2010 Page 113
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Quality of service (QoS). By priori
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Figure 4: WCDMA-HSPA Voice and Data
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It is clear that both EDGE and UMTS
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TechnologyNameType Characteristics
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Europe are providing operators with
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MHz, in Japan at 1500 MHz and in Eu
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and VoIP operation. These approache
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will be able to build applications
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Leveraging this success, operators
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VoIP for HSPA. Since LTE uses an IP
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Figure 10: Different Deployment Sce
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Figure 11: Radio Resource Managemen
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IEEE 802.16e-2005 and now IEEE 802.
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attempts, no terrestrial wireless-d
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DownlinkPeakNetworkSpeedPeakand/orT
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DownlinkUplinkPeakNetworkSpeedPeaka
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Figure 13: HSDPA Performance of a 7
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Figure 15: HSPA+ Performance Measur
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Figure 17: LTE Throughput in Variou
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Figure 19: Latency of Different Tec
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Figure 20: Performance Relative to
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Figure 21: Comparison of Downlink S
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Incremental redundancy in error cor
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Figure 23: Comparison of Voice Spec
Page 61 and 62: Figure 24: Relative Volume of Subsc
Page 63 and 64: Technology EDGE/HSPA/LTE CDMA2000 W
Page 65 and 66: capacity of OFDMA-based approaches
Page 67 and 68: In this section, we consider differ
Page 69 and 70: To understand the evolution of data
Page 71 and 72: how EDGE functions including networ
Page 73 and 74: Alternatively, the original number
Page 75 and 76: In today’s EDGE systems, f12 thro
Page 77 and 78: DAS-9 16 QAM 217.6DAS-10 32 QAM 262
Page 79 and 80: Operators can also use their entire
Page 81 and 82: HSDPAHSPA refers to networks that s
Page 83 and 84: Figure 33: User DiversitySignal Qua
Page 85 and 86: Initial devices enabled peak user r
Page 87 and 88: “single-stream MIMO” or “MIMO
Page 89 and 90: Given the large amount of backhaul
Page 91 and 92: connection between the network and
Page 93 and 94: Figure 39: HSPA One-Tunnel Architec
Page 95 and 96: Figure 40: High-Speed Forward Acces
Page 97 and 98: elatively straightforward changes i
Page 99 and 100: on LTE began in 2004 with an offici
Page 101 and 102: Figure 45: LTE OFDMA Downlink Resou
Page 103 and 104: Single base-station antenna versus
Page 105 and 106: TX antennas and most devices will o
Page 107 and 108: Figure 48: Evolution of Voice in an
Page 109 and 110: Table 19: IMT-Advanced Requirements
Page 111: Beyond wider bandwidths, LTE-Advanc
Page 115 and 116: Different technologies spanning Wi-
Page 117 and 118: stations, and because of the narrow
Page 119 and 120: Support for new radio-access networ
Page 121 and 122: AbbreviationsThe following abbrevia
Page 123 and 124: GBR - Guaranteed Bit RateGbyte - Gi
Page 125 and 126: PHY - Physical LayerPMI - Precoding
Page 127 and 128: Additional Information3G Americas m
Page 129 and 130: Ericsson: HSPA voice migration, Jun
Page 131 and 132: SNL Kagan: press release, “SNL Ka
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3GPP Broadband Evolution to IMT-Advanced - 4G Americas

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