This work investigates the application of nonorthogonal multiple access (NOMA) scheme for the uplink of wireless powered communication networks (WPCN). We maximize the sum rate by jointly designing of the time allocation, the downlink energy beamforming and receiver beamforming. To solve this nonconvex problem, a method of two stages optimization is proposed. In the first stage, we apply the se...

For a wireless mesh network with randomly placed devices, we analyze the impact of beamforming on the statistics of the signal attenuation, interference, and SIR between devices. We show that simple random direction beamforming performs equally well as omni-directional transmission if no MAC layer is present. Optimized beamforming between transmitter-receiver pairs yields a much better SIR than...

In recent years, sensor network system has been proposed for various applications. In the past, most reported systems involve custom-made hardware. In this paper, we consider the use of Compaq iPAQ 3760s with their build-in StrongARM processors, ROM and RAM memories, and microphones and codecs for acoustic acquisition and processing, plus external wireless Ethernet cards for radio communication...

In this paper, a new spreading scheme, which consists of two stages of spreading, is considered for DS-CDMA systems. The data of a user is spread first with a long signature sequence and then with a short signature sequence. The scheme combines the advantages of the two types of spreading techniques and allows us to suppress MAI by performing both beamforming and multiuser detection efficiently...

Traditional methods for beamforming can be grouped in two families, the time reference beamformer and the spatial reference beamforming. Nevertheless, the increasing demand on receivers for location systems and high bandwidth over frequency selective fading able to properly manage multipath and co-channel interference motivates the need for versatile processing able to cope with both problems. ...

Hybrid beamforming is a promising concept to achieve high data rate transmission at millimeter waves. To implement it in a transceiver, many references optimally adapt to a high-dimensional multi-antenna channel but more or less ignore the complexity of the channel estimation. Realizing that received coupling coefficients of the channel and pairs of possible analog beamforming vectors can be us...

The performance of broadband millimeter-wave (mmWave) RF architectures, is generally determined by mathematical concepts such as the Shannon capacity. These systems have also to obey physical laws such as the conservation of energy and the propagation laws. Taking the physical and hardware limitations into account is crucial for characterizing the actual performance of mmWave systems under cert...

On a multi-antenna downlink channel, separation of multiple users by transmit beamforming enables simultaneous transmission from the base station to the users, resulting in very high throughput. This paper proposes and analyzes a practical scheme for joint orthogonal beamforming and scheduling, which is enabled by feedback of quantized channel state information. In this approach, the base stati...

This paper addresses the array processing problems (mainly focuses on direction of arrival estimation and beamforming) of mobile communication system using linear antenna arrays in high impulsive noise environment. One possible way to simulate the impulsive noise is to introduce alpha-stable distribution as the noise model. In order to reduce the computational complexity, the problems of DOA an...