Radio transmissions traditionally use one antenna at the transmitter and one antenna at the receiver. This system is termed Single Input Single Output (SISO). Both the transmitter and the receiver have one RF chain (that's coder and modulator). SISO is relatively simple and cheap to implement and it has been used age long since the birth of radio technology. It is used in radio and TV broadcast...

Introduction Measurement and control of gain and reflected power in wireless transmitters are critical auxiliary functions that are often overlooked. The power reflected back from an antenna is specified using either the Voltage Standing Wave Ratio (VSWR) or Reflection Coefficient (also referred to as Return Loss). Poor VSWR can cause shadowing in a TV broadcast system as the signal reflected o...

Directional antennas provide numerous benefits, such as higher gains, increased transmission range, and lower interferences. In this paper, we propose a reliable broadcast protocol for directional antenna referred to as beam table-based reliable broadcast for directional antennas (BTRB). The BTRB employs (1) ACK-based scheme to provide full reliability; (2) spatio-temporal ACK combination to re...

This paper first studies the homogeneous 3-user 2×1 broadcast channel (BC) with no CSIT. We show a sufficient condition for it to achieve the optimal 3 2 degrees of freedom (DoF) by using Blind Interference Alignment (BIA). BIA refers to the interference alignment method without the need of CSIT. It further studies the 2×1 broadcast network in which there are K ≥ 3 homogeneous single-antenna us...

In wireless data networks, communication is particularly susceptible to eavesdropping due to its broadcast nature. Security and privacy systems have become critical for wireless providers and enterprise networks. This paper considers the problem of secret communication over the Gaussian broadcast channel, where a multi-antenna transmitter sends independent confidential messages to two users wit...

Multicarrier systems suffer from the high peak-to-average power ratio (PAR) of their transmit signal. In order to overcome this issue, peak-power reduction schemes have been developed. One of the most popular technique is selected mapping (SLM). Recently, a variant of SLM for single-antenna systems was proposed. This scheme considers temporally consecutive OFDM frames to achieve a further gain ...

Consider a wireless communication system where the base station has multiple antennas and users have a single antenna. For both the multiple access and broadcast channels, the sum capacity scales at best linearly with the number of antennas at the base station and double logarithmically with the number of users as the user pool grows asymptotically. Achieving this optimal capacity scaling poten...

A four column Smart antenna array fed by a 4x4 Butler matrix augmented by a variable beam shaping network has been designed and simulated. It is demonstrated that using only three phase shifters within the beam shaping network provides dynamic beam flexibility including: four narrow switched beams, a right shaped beam, a left shaped beam and a broad broadcast channel beam. The shaped beams conc...

When the conductors of an antenna have length greater than λ/4, where λ is the broadcast wavelength, the current distribution may have nodes where the current vanishes. If so, it would seem that the conductors could be cut at these nodes, creating small gaps, without any effect on the radiation of the antenna. The possibility of nodes in the current distribution of an antenna is suggested by th...