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

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There are also a number of planned improvements for CDMA2000 1xRTT in a versionreferred to as 1x-Advanced that will significantly increase voice capacity, doubling it if allenhancements are implemented. CDMA operators are not only considering 1x-Advancedas a means to increase voice capacity, but as a means to free up spectrum to supportmore data services, such as deploying more EV-DO carriers or deploying LTE.3GPP2 has defined technical means to integrate CDMA2000 networks with LTE along twoavailable approaches:1. Loose coupling. This involves little or no inter-system functionality, and resourcesare released in the source system prior to handover execution.2. Tight coupling. The two systems intercommunicate with network-controlled makebefore-breakhandovers. Tight coupling allows maintenance of data sessions withthe same IP address. This will likely involve a more complex implementation thanloose coupling.CDMA2000 is clearly a viable and effective wireless technology and, to its credit, many ofits innovations have been brought to market ahead of competing technologies.WiMAXWiMAX has emerged as a potential alternative to cellular technology for wide-areawireless networks. Based on OFDMA and recently accepted by the ITU as an IMT-2000(3G technology) under the name OFDMA TDD Wireless Metropolitan Area Network(WMAN), WiMAX is trying to challenge existing wireless technologies—promising greatercapabilities and greater efficiencies than alternative approaches such as HSPA. But asWiMAX, particularly mobile WiMAX, has come closer to reality, vendors have continued toenhance HSPA and perceived WiMAX advantages are no longer apparent. Moreover, LTEnetworks are now beginning to be deployed.Instead, WiMAX has gained the greatest traction in developing countries as an alternativeto wireline deployment. In the United States, Clearwire, Sprint Nextel and others (Intel,Google, Comcast, Time Warner Cable, and Bright House Networks) have created a jointventure to deploy a nationwide WiMAX network. In July 2010, this network was availablein 44 markets across the U.S. 38The original specification, IEEE 802.16, was completed in 2001 and intended primarily fortelecom backhaul applications in point-to-point, line-of-sight configurations usingspectrum above 10 GHz. This original version of IEEE 802.16 uses a radio interface basedon a single-carrier waveform.The next major step in the evolution of IEEE 802.16 occurred in 2004 with the release ofthe IEEE 802.16-2004 standard. It added multiple radio interfaces, including one basedon OFDM-256 and one based on OFDMA. IEEE 802.16-2004 also supports point-tomultipointcommunications, sub-10 GHz operation, and non-line-of-sightcommunications. Like the original version of the standard, operation is fixed, meaningthat subscriber stations are typically immobile. Potential applications include wirelessInternet Service Provider (ISP) service and local telephony bypass (as an alternative tocable modem or DSL service). Vendors can design equipment for either licensed orunlicensed bands.38 Source: Clearwire Press Release, “Clearwire Brings CLEAR 4G to Merced and Visalia, California,” July1, 2010.Transition to 4G: 3GPP Broadband Evolution to IMT-Advanced, Rysavy Research/3G Americas, Aug 2010 Page 36
IEEE 802.16e-2005 and now IEEE 802.16-2009 add mobility capabilities includingsupport for radio operation while mobile, handovers across base stations, and handoversacross operators. Unlike IEEE 802.16-2004, which operates in both licensed andunlicensed bands, IEEE 802.16e-2005 (referred to as mobile WiMAX) makes the mostsense in licensed bands. Current WiMAX profiles emphasize TDD operation. Mobile WiMAXnetworks are not backward-compatible with IEEE 802.16-2004 networks.Vendors deliver WiMAX Forum-certified equipment that conforms to subsets of IEEE802.16e-2005 or IEEE 802.16-2009 as defined today. The IEEE itself does not define acertification process.Current mobile WiMAX networks use 2X2 MIMO or 4X2 MIMO, TDD, and 10 MHz radiochannels in a profile defined by the WiMAX Forum known as WiMAX Wave 2 or, moreformally, as WiMAX System Profile 1.0. Beyond Release 1.0, the WiMAX Forum hasdefined a new profile called WiMAX Release 1.5. This profile includes various refinementsintended to improve efficiency and performance and could be available for deployment ina similar timeframe as LTE.Release 1.5 enhancements include Medium Access Control (MAC) overhead reductions forVoIP (persistent scheduling), handover optimizations, load balancing, location-basedservices support, Frequency Division Duplex (FDD) operation, 64 QAM in the uplink,downlink adaptive modulation and coding, closed-loop MIMO (FDD mode only), anduplink MIMO. There are no current Release 1.5 deployment plans.A subsequent version, Mobile WiMAX 2.0, will be designed to address the performancerequirements being developed in the ITU IMT-Advanced Project and will be standardizedin a new IEEE standard, IEEE 802.16m. According to Sprint Nextel, IEEE 802.16m will beavailable in 2011. 39 Deployment, however, depends on not just finalization of the IEEEspecifications, but of associated WiMAX Forum profiles and associated certificationprograms.WiMAX employs many of the same mechanisms as HSPA to maximize throughput andspectral efficiency, including high-order modulation, efficient coding, adaptive modulationand coding, and Hybrid Automatic Repeat Request (HARQ). The principal difference fromHSPA is IEEE 802.16e-2005’s use of OFDMA. As discussed in the section “TechnicalApproaches (TDMA, CDMA, OFDMA)” above, OFDM provides a potential implementationadvantage for wide radio channels (for example, 10 to 20 MHz). In 5 to 10 MHz radiochannels, there is no evidence indicating that WiMAX will have any performanceadvantage compared with HSPA+.It should be noted, however, that IEEE 802.16e-2005 contains some aspects that maylimit its performance, particularly in scenarios in which a sector contains a large numberof mobile users. The performance of the MAC layer is inefficient when scheduling largenumbers of users, and some aspects—such as power control of the mobile station—areprovided using MAC signaling messages rather than the fast power control used inWCDMA and other technologies. Thus, while WiMAX uses OFDMA, the performance willlikely be somewhat less than HSPA due to increased overhead and other design issues.Relative to LTE, WiMAX has the following technical disadvantages: 5 msec frames insteadof 1 msec frames, Chase combining instead of incremental redundancy, coarsergranularity for modulation and coding schemes and vertical coding instead of horizontalcoding. 40 One deployment consideration is that TDD requires network synchronization. It39 Ali Tabassi, Sprint Nextel, Fierce Wireless Webcast, “WiMAX: Mobilizing the Internet”, March 5, 2008.40 IEEE International Symposium on Personal, Indoor and Mobile Radio Communications: AndersFuruskär et al “The LTE Radio Interface – Key Characteristics and Performance,” 2008.Transition to 4G: 3GPP Broadband Evolution to IMT-Advanced, Rysavy Research/3G Americas, Aug 2010 Page 37
Page 11 and 12: Quality of service (QoS). By priori
Page 13: Figure 4: WCDMA-HSPA Voice and Data
Page 16 and 17: It is clear that both EDGE and UMTS
Page 18: TechnologyNameType Characteristics
Page 21 and 22: Europe are providing operators with
Page 23 and 24: MHz, in Japan at 1500 MHz and in Eu
Page 25 and 26: and VoIP operation. These approache
Page 27 and 28: will be able to build applications
Page 29 and 30: Leveraging this success, operators
Page 31 and 32: VoIP for HSPA. Since LTE uses an IP
Page 33 and 34: Figure 10: Different Deployment Sce
Page 35: Figure 11: Radio Resource Managemen
Page 39 and 40: attempts, no terrestrial wireless-d
Page 41 and 42: DownlinkPeakNetworkSpeedPeakand/orT
Page 43 and 44: DownlinkUplinkPeakNetworkSpeedPeaka
Page 45 and 46: Figure 13: HSDPA Performance of a 7
Page 47 and 48: Figure 15: HSPA+ Performance Measur
Page 49 and 50: Figure 17: LTE Throughput in Variou
Page 51 and 52: Figure 19: Latency of Different Tec
Page 53 and 54: Figure 20: Performance Relative to
Page 55 and 56: Figure 21: Comparison of Downlink S
Page 57 and 58: Incremental redundancy in error cor
Page 59 and 60: 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
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“single-stream MIMO” or “MIMO
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Given the large amount of backhaul
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connection between the network and
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Figure 39: HSPA One-Tunnel Architec
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Figure 40: High-Speed Forward Acces
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elatively straightforward changes i
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on LTE began in 2004 with an offici
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Figure 45: LTE OFDMA Downlink Resou
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Single base-station antenna versus
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TX antennas and most devices will o
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Figure 48: Evolution of Voice in an
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Table 19: IMT-Advanced Requirements
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Beyond wider bandwidths, LTE-Advanc
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As discussed in more detail in the
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Different technologies spanning Wi-
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stations, and because of the narrow
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Support for new radio-access networ
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AbbreviationsThe following abbrevia
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GBR - Guaranteed Bit RateGbyte - Gi
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PHY - Physical LayerPMI - Precoding
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Additional Information3G Americas m
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Ericsson: HSPA voice migration, Jun
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SNL Kagan: press release, “SNL Ka
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3GPP Broadband Evolution to IMT-Advanced - 4G Americas

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