Technical Solutions for the 3G Long-Term Evolution
Third-generation (3G) wireless systems, based on wideband code-division multiple access (WCDMA) radio access technology, are now being deployed on a broad scale all over the world. The first step in the evolution of WCDMA has also been taken by the Third Generation Partnership Project (3GPP) through the introduction of high-speed downlink packet access (HSDPA) and enhanced uplink . These technologies provide 3GPP with a radio access technology that will be highly competitive in the mid-term future.
However, user and operator requirements and expectations are continuously evolving, and competing radio access technologies are emerging. Thus, it is important for 3GPP to start considering the next steps in 3G evolution, in order to ensure 3G competitiveness in a 10-year perspective and beyond. As a consequence, 3GPP has launched the study item Evolved UTRA and UTRAN, the aim of which is to study means to achieve further substantial leaps in terms of service provisioning and cost reduction. The overall target of this long-term evolution (LTE) of 3G, sometimes also referred to as Super-3G, is to arrive at an evolved radio access technology that can provide service performance on a par with or even exceeding that of current fixed line accesses, at substantially reduced cost compared to current radio access technologies. As it is generally assumed that there will be a convergence toward the use of Internet Protocol (IP)-based protocols (i.e., all services in the future will be carried on top of IP), the focus of this evolution should be on enhancements for packet-based services. 3GPP aims to conclude on the evolved 3G radio access technology in 2007, with subsequent initial deployment in the 2009–2010 timeframe. At this point, it is important to emphasize that this evolved radio access network (RAN) is an evolution of current 3G networks, building on already made investments.
Among others, the targets of long-term 3G evolution are :
• The possibility to provide significantly higher data rates than do the current steps of 3G evolution (HSDPA and enhanced uplink), with target peak data rates up to 100 Mb/s for the downlink and up to 50 Mb/s for the uplink.
• The capability to provide three to four times higher average throughput and two to three times higher cell-edge throughput (measured at the 5th percentile) when compared to 3GPP Release 6 (Rel-6) systems (i.e., systems based on HSDPA and enhanced uplink).
• Improved spectrum efficiency, targeting an improvement on the order of a factor of 3 compared to current standards.
• Significantly reduced control and user plane latency, with a target of less than 10 ms user plane RAN round-trip time (RTT)and less than 100 ms channel setup delay
• Reduced cost for operator and end user.
• Spectrum flexibility, enabling deployment in different spectrum allocations. This involves a smooth migration into other frequency bands, including those currently used for second-generation (2G) cellular