A system-level assessment of Uplink CoMP in LTE-A Heterogeneous Networks

In Long Term Evolution-Advanced (LTE-A) heterogeneous networks (HetNets), small cells are deployed within the coverage area of macrocells having 1 : 1 frequency reuse. The coexistence of small cells and a macrocell in the same frequency band poses cross-tier interference which causes outage for macrocells users and/or small cell users. To address this problem, in this paper, we propose two algorithms that consider the received interference level at the evolved NodeB (eNB) while allocating transmit power to the users. In the proposed algorithm, the transmit power of all users is updated according to the target and instantaneous signal-to-noise-plus-interference ratio (SINR) condition as long as the effective received interference at the serving eNB is below the given threshold. Otherwise, if the effective received interference at the eNB is greater than the threshold, the transmit power of small cell users is gradually reduced in order to guarantee the target SINR for all macrocells users, aiming for zero-outage for macrocells users at the cost of an increased outage ratio for small cell users. Further, in the second algorithm, the transmit power of all users is additionally controlled by the power headroom report that considers the current channel condition while updating the transmit power which results in the outage ratio decreasing for small cell users. The extensive system-level simulations show significant improvements in the average throughput and outage ratio when compared with the conventional transmit power control technique.

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System level results of a novel energy efficient time resource scheduling method in 3GPP LTE-Advanced heterogeneous networks

2013 8th International Conference on Communications and Networking in China (CHINACOM) ◽

10.1109/chinacom.2013.6694664 ◽

2013 ◽

Author(s):

Yuan Gao ◽

Yi Li ◽

Hongyi Yu ◽

Xianfeng Wang ◽

Shihai Gao

Keyword(s):

Heterogeneous Networks ◽

Energy Efficient ◽

Resource Scheduling ◽

System Level ◽

3Gpp Lte ◽

Lte Advanced ◽

Scheduling Method ◽

Time Resource

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Interference Mitigation through Successive Cancellation in Heterogeneous Networks

ISRN Communications and Networking ◽

10.1155/2013/146024 ◽

2013 ◽

Vol 2013 ◽

pp. 1-18 ◽

Cited By ~ 3

Author(s):

Onur Sahin ◽

Jialing Li ◽

Enoch Lu ◽

Yingxue Li ◽

Philip J. Pietraski

Keyword(s):

Performance Improvement ◽

Heterogeneous Networks ◽

Interference Cancellation ◽

Interference Mitigation ◽

Interference Management ◽

System Level ◽

Weighted Sum ◽

Successive Cancellation ◽

Management Scheme ◽

System Level Simulations

We present a practical interference management scheme for heterogeneous networks (HetNets). The underlying ideas are based on (i) Han-Kobayashi-type message splitting (MS) where the receivers decode and cancel “part” of the interference which is accordingly optimized by the transmitters to ensure decoding and (ii) opportunistic interference cancellation (OIC) where the interfering transmitters act independently of the receivers that employ interference cancellation. We develop a novel transmission and reception scheme, called joint MS and OIC (MS-OIC), that engages both MS and OIC to account for a practical HetNet system with multiple macrocells and femtocells. The MS component includes a precoder design that judiciously maximizes the weighted sum throughput via the enabling of interference cancellation. A system design along with a novel scheduler that facilitates MS-OIC in a general HetNet system is also developed. System level simulations for a general HetNet system are presented, and the proposed MS-OIC scheme is compared with benchmark schemes such as Coordinated Beamforming (CBF) and joint CBF and Almost Blank Subframes (CBF-ABS). It is observed that the proposed MS-OIC scheme improves the macrocell throughput substantially, balances the achievable rates between the macrocell and femtocell users, and provides significant outage performance improvement in the system.

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