Effective October 1, 2012, QUALCOMM Incorporated completed a corporate reorganization in which the assets of certain of its businesses and groups, as well as the stock of certain of its direct and indirect subsidiaries, were contributed to Qualcomm Technologies, Inc. (QTI), a wholly-owned subsidiary of QUALCOMM Incorporated. Learn more about these changes

You are here

Home › Research › Projects › LTE Advanced

LTE Advanced: Heterogeneous Networks

Qualcomm Research has been working on enhancing LTE network capacity and the broadband user experience in a ubiquitous and cost-effective manner.

Since radio link performance is approaching theoretical limits, the next performance and capacity leap will come from an evolution of network topology by using a mix of macro cells and small cells in a co-channel deployment. Qualcomm has been spearheading the introduction of heterogeneous network techniques in LTE Advanced, including enhanced inter-cell interference coordination (eICIC) in the network and advanced terminal receivers with interference cancellation (IC). Using these techniques, LTE Advanced heterogeneous networks significantly improve the spectrum efficiency per unit area and provide a uniform broadband user experience.

Details

LTE Advanced Heterogeneous Networks (HetNets) use a mix of macro, pico, femto and relay basestations, effectively bringing the network closer to the user. To deliver high spectral efficiency per unit area, advanced techniques are needed to manage and control interference when low power small cells are added to macro cells in the same channel. Qualcomm has developed two LTE Advanced techniques, enhanced inter-cell interference coordination and advanced terminal receivers with interference cancellation (eICIC/IC) to provide a performance leap for heterogeneous networks in LTE.

LTE Advanced HetNets will support Range Expansion and Resource Partitioning with an eICIC software upgrade to a LTE-R8 network. Range Expansion allows more user terminals to benefit directly from low-power base-stations such as picos, femtos and relays. Adaptive inter-cell interference coordination using Resource Partitioning provides smart resource allocation amongst interfering cells and improves inter-cell load balancing in heterogeneous networks. Advanced UE receivers cancel interference of legacy overhead channels from interfering cells to enable full Range Expansion of low-power small cells.

The eICIC feature has been standardized in 3GPP Rel. 10 under the LTE Advanced framework. Qualcomm R&D and other 3GPP participants are leading the standardization of HetNets features. Qualcomm R&D has also built a prototype to demonstrate and test these features in OTA heterogeneous networks in San Diego.

For an LTE operator that needs to significantly increase network capacity, deploying LTE Advanced HetNets and using 802.11 Wi-Fi access points (APs) in unlicensed spectrum offers two complementary options to offload macro user traffic. Based on our study, with the same number of low-power nodes, pico cells offer a superior performance to Wi-Fi APs due to expanded coverage of LTE Advanced pico cells. Wi-Fi is effective in improving the user experience when a significant portion of users are located in the vicinity of hotspots.