Deployment of the first LTE-Advanced service is expected to be around 2013 to 2014, with limited set of features. Not all the advanced technologies will be implemented in the beginning, but the rest will be "added-on" as the various conditions are cleared. Such conditions may include radio regulations, frequency allocations, and some technical barriers. Many of the new features are expected to be software upgrades on LTE nodes.
Unlike the general expectations of 4G, LTE-Advanced will not initially reach 1 Gbps or even 600 Mbps. One of the biggest reasons is the spectrum, which is strictly controlled by governments. Currently, only the 3.5 GHz spectrum is going to be assigned for wireless broadband in Japan, but it will not become available until 2014 to 2015. NTT docomo has announced its plan to start LTE-Advanced service with 40 MHz bandwidth on the 3.5 GHz spectrum, which is enough to achieve 1.2 Gbps speed theoretically. However, 8x8 MIMO technology required for such link speed will not be technically possible by 2015.
On the other hand, LTE services on 2 GHz spectrum will be able to provide speeds of around 100 Mbps in 2015. LTE-Advanced will only achieve the same speed as the existing LTE services at this point, or in the best case, it may be able to reach up to 300 Mbps with 2x2 MIMO and Carrier Aggregation on 40 MHz bandwidth. Thus, LTE-Advanced will not initially achieve full spec services, but it only indicates the roadmap for the future enhancements.
LTE-Advanced is the real 4G specification that greatly enhances the performance of existing LTE services. Although the maximum link speed may not greatly exceed the current LTE in the initial stage, deployment of LTE-Advanced will be an important milestone to set a clear path for the beginning of true wireless broadband.
