LTE Advanced: 3GPP Solution for IMT-Advanced

4.7 Conclusions

In the previous sections, we have covered the LTE downlink carrier aggregation principles as defined in 3GPP Release 10 specifications. The downlink carrier aggregation is an attractive approach to improve not only the available peak data rates, but also the user capacity, as well as in the average, but also at the cell edge, without adding more transmission or receive antennas compared to the Release 8 LTE implementation. The use of single uplink in combination with two (or more) downlink carriers allows having minimum impact to the uplink link budget with only an extra switch needed in the RF path. The first phase band combinations with actual market interest (following the few introductory cases to set up to prime the procedure to define the necessary requirements) to be completed during 2012 enable going to peak downlink data rates in the order of 300 Mbps with a two antenna MIMO operation. With more bands and more antennas the theoretical data rates range up to 3 Gbps. The downlink carrier aggregation can clearly be expected to be the most popular feature in the practical network deployments due to the major benefits achievable with reasonable complexity. This development is also visible in the major interest from the LTE network operators for the band combinations for different frequency bands.