Transition to 4G: 3GPP Broadband Evolution to IMT-Advanced

This paper discusses the evolution of EDGE, HSPA enhancements, 3GPP LTE, the capabilities of these technologies, and their position relative to other primary competing technologies. It explains how these technologies fit into the ITU roadmap that leads to IMT-Advanced. The following are some of the important observations and conclusions of this paper:

• The wireless technology roadmap now extends to IMT-Advanced with LTE-Advanced being one of the first technologies defined to meet IMT-Advanced requirements. LTEAdvanced will be capable of peak throughput rates that exceed 1 gigabit per second (Gbps).
• Future networks will be networks of networks, consisting of multiple-access technologies, multiple bands, widely-varying coverage areas, all self-organized and self-optimized.
• GSM-HSPA1 has an overwhelming global position in terms of subscribers, deployment, and services. Its success will continue to marginalize other wide-area wireless technologies.
• In current deployments, HSPA users regularly experience throughput rates well in excess of 1 megabit per second (Mbps) under favorable conditions, on both downlinks and uplinks, with 4 Mbps downlink speed commonly being measured. Planned enhancements such as dual-carrier operation will double peak user-achievable throughput rates.
• HSPA+ provides a strategic performance roadmap advantage for incumbent GSMHSPA operators. Features such as multi-carrier operation, Multiple Input Multiple Output (MIMO), and higher-order modulation offer operators multiple options for upgrading their networks, with many of these features (e.g., multi-carrier, higherorder modulation) being available as network software upgrades. With all planned features implemented, HSPA+ peak rates will eventually reach 168 Mbps.
• HSPA+ with 2x2 MIMO, successive interference cancellation, and 64 Quadrature Amplitude Modulation (QAM) is more spectrally efficient than competing technologies including Worldwide Interoperability for Microwave Access (WiMAX) Release 1.0.
• The 3GPP OFDMA approach used in LTE matches or exceeds the capabilities of any other OFDMA system. Peak theoretical downlink rates are 326 Mbps in a 20 MHz channel bandwidth. LTE assumes a full Internet Protocol (IP) network architecture, and it is designed to support voice in the packet domain.
• LTE has become the technology platform of choice as GSM-UMTS and Code Division Multiple Access (CDMA)/One Carrier Evolved, Data Optimized (EV-DO) operators are making strategic, long-term decisions on their next-generation platforms.
• GSM-HSPA will comprise the overwhelming majority of subscribers over the next five to ten years, even as new wireless technologies are adopted. The deployment of LTE and its coexistence with UMTS-HSPA will be analogous to the deployment of UMTSHSPA and its coexistence with GSM.
• 3GPP has made significant progress on how to enhance LTE to meet the requirements of IMT-Advanced in a project called LTE-Advanced. LTE-Advanced is expected to be the first true 4G system available. Specifications are scheduled to be completed in March of 2011, with earliest availability for deployment in 2012.
• HSPA-LTE has significant economic advantages over other wireless technologies.
• WiMAX has developed an ecosystem supported by many companies, but it will still represent only a very small percentage of wireless subscribers over the next five years.
• EDGE technology has proven extremely successful and is widely deployed on GSM networks globally. Advanced capabilities with Evolved EDGE can double and eventually quadruple current EDGE throughput rates, halve latency, and increase spectral efficiency.
• EPC will provide a new core network that supports both LTE and interoperability with legacy GSM-UMTS radio-access networks and non-3GPP-based radio access networks. Policy-based charging and control provides flexible quality-of-service management,
  enabling new types of applications, as well as billing arrangements.
• Innovations such as EPC and UMTS one-tunnel architecture will “flatten” the network, simplifying deployment and reducing latency.

This paper begins with an overview of the market, looking at trends, EDGE and UMTS-HSPA deployments, and market statistics. It then examines the evolution of wireless technology, particularly 3GPP technologies, including spectrum considerations, core-network evolution, broadband-wireless deployment considerations, and a feature and network roadmap. Next, the paper discusses other wireless technologies including Code Division Multiple Access 2000 (CDMA2000) and WiMAX. Finally, it compares the different wireless technologies technically, based on features such as performance and spectral efficiency.

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