90 citations · 428 across the 38 of their papers we have counts for
11 papers · 1 filter
Achievable Degrees-of-Freedom of the K-user SISO Interference Channel with Blind Interference Alignment using Staggered Antenna Switching
Ahmed M. Alaa, Mahmoud H. Ismail
In this letter, we present the first characterization for the achievable Degrees-of-Freedom (DoF) by Blind Interference Alignment (BIA) using staggered antenna switching in the …
Stable Throughput Region of Cognitive-Relay Networks with Imperfect Sensing and Finite Relaying Buffer
Ahmed M. Alaa
In this letter, we obtain the stable throughput region for a cognitive relaying scheme with a finite relaying buffer and imperfect sensing. The analysis investigates the effect of…
Opportunistic Beamforming using Dumb Basis Patterns in Multiple Access Cognitive Channels
Ahmed M. Alaa, Mahmoud H. Ismail, Hazim Tawfik
In this paper, we investigate multiuser diversity in interference-limited Multiple Access (MAC) underlay cognitive channels with Line-of-Sight interference (LoS) from the secondary…
Band-Sweeping M-ary PSK (BS-M-PSK) Modulation and Transceiver Design
Ahmed M. Alaa
Channel Estimation is a major problem encountered by receiver designers for wireless communications systems. The fading channels encountered by the system are usually time variant…
Random Aerial Beamforming for Underlay Cognitive Radio with Exposed Secondary Users
Ahmed M. Alaa, Mahmoud H. Ismail, Hazim Tawfik
In this paper, we introduce the exposed secondary users problem in underlay cognitive radio systems, where both the secondary-to-primary and primary-to-secondary channels have a Li…
On the Capacity of the Underwater Acoustic Channel with Dominant Noise Sources
Mustafa A. Kishk, Ahmed M. Alaa
This paper provides an upper-bound for the capacity of the underwater acoustic (UWA) channel with dominant noise sources and generalized fading environments. Previous works have sh…
Opportunistic Spectrum Sharing using Dumb Basis Patterns: The Line-of-Sight Interference Scenario
Ahmed M. Alaa, Mahmoud H. Ismail, Hazim Tawfik
We investigate a spectrum-sharing system with non-severely faded mutual interference links, where both the secondary-to-primary and primary-to-secondary channels have a Line-of-Sig…
Spectrum Sensing Via Reconfigurable Antennas: Fundamental Limits and Potential Gains
Ahmed M. Alaa, Mahmoud H. Ismail, Hazim Tawfik
We propose a novel paradigm for spectrum sensing in cognitive radio networks that provides diversity and capacity benefits using a single antenna at the Secondary User (SU) receive…
Globally Optimal Cooperation in Dense Cognitive Radio Networks
Ahmed M. Alaa, Omar A. Nasr
The problem of calculating the local and global decision thresholds in hard decisions based cooperative spectrum sensing is well known for its mathematical intractability. Previous…
Defeating the Eavesdropper: On the Achievable Secrecy Capacity using Reconfigurable Antennas
Ahmed M. Alaa
In this paper, we consider the transmission of confidential messages over slow fading wireless channels in the presence of an eavesdropper. We propose a transmission scheme that em…
Spectrum Sensing Via Reconfigurable Antennas: Is Cooperation of Secondary Users Indispensable?
Ahmed M. Alaa, Mahmoud H. Ismail, Hazim Tawfik
This work presents an analytical framework for characterizing the performance of cooperative and noncooperative spectrum sensing schemes by figuring out the tradeoff between the ac…