INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS Int. J. Commun. Syst. (2012) Published online in Wiley Online Library (wileyonlinelibrary.com). DOI: 10.1002/dac.2483 High-resolution compressive channel estimation for broadband wireless communication systems Guan Gui * ,† , Wei Peng and Fumiyuki Adachi Department of Communication Engineering, Graduate School of Engineering, Tohoku University,Sendai, Japan SUMMARY Broadband channel is often characterized by a sparse multipath channel where dominant multipath taps are widely separated in time, thereby resulting in a large delay spread. Accurate channel estimation can be done by sampling received signal with analog-to-digital converter (ADC) at Nyquist rate and then estimating all channel taps with high resolution. However, these Nyquist sampling-based methods have two main disad- vantages: (i) demand of the high-speed ADC, which already exceeds the capability of current ADC, and (ii) low spectral efficiency. To solve these challenges, compressive channel estimation methods have been proposed. Unfortunately, those channel estimators are vulnerable to low resolution in low-speed ADC sam- pling systems. In this paper, we propose a high-resolution compressive channel estimation method, which is based on sampling by using multiple low-speed ADCs. Unlike the traditional methods on compressive channel estimation, our proposed method can approximately achieve the performance of lower bound. At the same time, the proposed method can reduce communication cost and improve spectral efficiency. Numerical simulations confirm our proposed method by using low-speed ADC sampling. Copyright © 2012 John Wiley & Sons, Ltd. Received 21 May 2012; Revised 12 September 2012; Accepted 21 November 2012 KEY WORDS: high-resolution channel; compressive channel estimation; sub-Nyquist rate sampling; compressive sensing 1. INTRODUCTION With the number of wireless subscribers increasing every day, various wireless devices, for exam- ple, smart phones, netbooks, and laptops, generate massive data traffic on the rise. An authoritative industry report predicts that mobile-generated traffic will exceed that from fixed personal computers (PCs) by 2015, underscoring the fact that most information and communication technology services may be expected to migrate to portable mobile devices over the next few years. This trend toward mobile platforms has significant implications for radio technology and wireless networks, which will enable this paradigm shift, as well as for the wide variety of internet applications currently supported by fixed network devices such as PCs and televisions [1]. To satisfy the greedy demand of high-speed data services, high data rate broadband communication is an indispensable technique [2] in the next-generation communication systems. Broadband signal transmission over multipath channel is often susceptible to frequency-selective fading. Hence, the accurate channel state information is required at the receiver for coherent detec- tion. On the basis of the assumption of rich multipath channel, linear channel estimation meth- ods have been proposed for different advanced systems [3–10]. A typical diagram of high-speed ADC-based channel estimation method is shown in Figure 1. However, these linear methods pose *Correspondence to: Guan Gui, Department of Communication Engineering, Graduate School of Engineering, Tohoku University, Sendai, Japan. † E-mail: gui@mobile.ecei.tohoku.ac.jp Copyright © 2012 John Wiley & Sons, Ltd.