# Heterogeneous Cellular Networks Using Wireless Backhaul: Fast Admission Control and Large System Analysis

Jian Zhao, Tony Q.S. Quek, Zhongding Lei

Research output: Contribution to journalArticlepeer-review

45 Citations (Scopus)

## Abstract

We consider a heterogeneous cellular network with densely underlaid small cell access points (SAPs). Wireless backhaul provides the data connection from the core network to SAPs. To serve as many SAPs and their corresponding users as possible with guaranteed data rates, admission control of SAPs needs to be performed in wireless backhaul. Such a problem involves joint design of transmit beamformers, power control, and selection of SAPs. In order to tackle such a difficult problem, we apply $\ell-1$-relaxation and propose an iterative algorithm for the $\ell-1$-relaxed problem. The selection of SAPs is made based on the outputs of the iterative algorithm, and we prove such an algorithm converges locally. Furthermore, this algorithm is fast and enjoys low complexity for small-to-medium sized systems. However, its solution depends on the actual channel state information, and resuming the algorithm for each new channel realization may be unrealistic for large systems. Therefore, we make use of the random matrix theory and also propose an iterative algorithm for large systems. Such a large-system iterative algorithm can produce the asymptotically optimum solution for the $\ell-1$-relaxed problem, which only requires large-scale channel coefficients irrespective of the actual channel realization. Near optimum results are achieved by our proposed algorithms in simulations.

Original language English 7115025 2128-2143 16 IEEE Journal on Selected Areas in Communications 33 10 https://doi.org/10.1109/JSAC.2015.2439471 Published - 2015 Oct 1

## All Science Journal Classification (ASJC) codes

• Computer Networks and Communications
• Electrical and Electronic Engineering

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