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An active quasi-circulator (AQC) operating at a frequency band ranging from 1.2–3.8 GHz is designed in a 0.18-μm CMOS process. To improve the isolation between AQC's ports common-gate (CG), common-source (CS) and common-drain (CD) configurations have been employed. To particularly improve the transmitter-to-receiver port isolation, out-of-phase cancellation is employed by making the transmit signal...
In a MIMO wireless communications system, a space-time block code specifies how the data symbols are transmitted over different antennas at different time instants. A hybrid space-time code attempts to obtain some of the available diversity and multiplexing gains, achieving low error probability and high data rate. The LD StBc-VBLAST hybrid code layers one spatial-multiplexing antenna (to increase...
A digital communications receiver requires precise symbol synchronization before the transmitted information can be recovered. Gardner's algorithm is a synchronizer that can acquire and track timing with only two samples per symbol, and it does not require prior carrier synchronization. In this paper, a feed-forward, all-digital version of Gardner's algorithm is presented. It is shown that this synchronizer...
The emerging market of the Internet of Things (IoT) requires new energy-efficient and low-complexity Multiple-Input-Multiple-Output (MIMO-) aided radio access technologies. This trend will have a profound impact on both the theory and practice of future communication networks, which will not be purely optimized for approaching the attainable capacity anymore, but will explicitly include the energy...
This paper presents numerical simulation results to evaluate the interference effect from maritime ESIM to 5G mobile service using 28GHz frequency band. An interference scenario considering the real deployment are established and the Minimum Coupling Loss method is used. From the numerical results, we confirm that the separate distance need to guarantee 5G service quality for outdoor environments...
This paper proposes a compact VHF-band OOK transmitter that uses coils for radiation as well as oscillation, eliminating the need for an external antenna. This feature contributes to fewer number of components, smaller volume and and lower cost. We prototyped the transmitter with 2.8 mm × 2.8 mm × 4.2 mm volume. For shortening the startup time and enabling high-speed communication, we devise a scheme...
A worst-case model of spurious resonances which can occur in electromagnetic system consisting of an antenna, cable and transmitter output filter (or receiver input filter) is proposed. These resonances may cause significant increase in power of spurious emissions for transmitting equipment and the decrease in out-of-band radiated susceptibility levels for receiving equipment. Three amplitude-frequency...
This paper investigates path loss characteristics for Vehicle-to-Infrastructure (V2I) communications in urban and suburban scenarios. We carried out measurements at 5.9 GHz. The transmitter antenna heights are 3.5 m and 1.5 m and the position of the receiver antenna is on the roof of the car. Then we analyzed the path loss characteristics by using the measured data. The results are helpful for the...
The design of massive MIMO, especially at millimeter waves, requires a trade-off between cost and power consumption, balancing the complexity and the performance in terms of achievable rate. A recent trend in the design is to split the pre-coding at the transmitter and the combining at the receiver into a digital and analog part, with hybrid analog-digital schemes. In this paper the effect of phase...
Index modulation (IM) technique is introduced in orthogonal frequency division multiplexing (OFDM) based systems as an extension of spatial modulation (SM) principle, assuming that information is delivered to the receiver not only through symbols sent by the transmitter, but also through indices of the selected active subcarriers' set. Index modulated OFDM can be very interesting solution for 5G systems,...
In this work, a two-user Rayleigh-faded asymmetric interference channel, where the interfering transmitter has two antennas and the other terminals have single antenna, is considered. Two encoding strategies based on single-user (SU) codes and multi-user (MU) codes, and two decoding strategies based on interference ignorant and joint decoding are considered. The diversity-multiplexing tradeoff (DMT)...
Impulse radio (IR) transmission is consider used in wireless personal area network (WPAN) for high speed and low power transmission and new innovation wireless technology. This paper propose a novel analysis of impulse radio transmission in WPAN for ultra wireless communications. The waveform distortion due to the antennas should be considered. The optimum and isotropic template receivers are considered...
Antenna correlation is prevalent in higher frequencies as well as in massive MIMO, thus the study of correlated MIMO broadcast channels is becoming a subject of increasing interest. This paper explores the fundamental limits of such systems, focusing on cases where correlation eigenspaces are neither independent nor identical, so that known beam-space division techniques do not directly apply. We...
It is well known that Massive MIMO systems (Multiple-input multiple-output) have high potential for future wireless broadband systems. However, high spectral and power efficiency requirements can be only achieved by multilevel modulations and efficient power amplification. This seems contradictory, due envelope variation of multilevel constellations that can compromise efficiency of power amplification...
In this paper, we study a single-user multiple-input single-output (MISO) system with constant envelope (CE) transmission. To enable the nonlinear mapping from a fixed receiver signal constellation to the transmitter CE signal vectors, the availability of perfect channel state information at the transmitter (CSIT) is assumed in existing literature. However, traditionally, CSIT needs to be acquired...
Real interference alignment is efficient in breaking-up a one-dimensional space over time-invariant channels into fractional dimensions. As such, multiple symbols can be simultaneously transmitted with fractional degrees-of-freedom (DoF). Of particular interest is when the one dimensional space is partitioned into two fractional dimensions. In such scenario, the interfering signals are confined to...
Multiple-input multiple-output (MIMO) is an essential technology for modern wireless communication systems. Spatial modulation (SM) is an evolving MIMO transmission scheme for energy-efficient massive MIMO systems. SM conveys the information of transmit antenna indices and modulated symbols in MIMO systems. A variant spatial permutation modulation (SPM) was further proposed to include transmit and...
In this paper, massive MIMO amplify-and-forward multi-pair relaying is considered to assist device-to-device (D2D) communications. The direct D2D communication is underlaid with the source-to-relay transmission in the first hop, hence the D2D signals are also received at the relay, which are then forwarded in the second hop, overlapping with the relay-to-destination transmission. Moreover, D2D users...
In this work, we consider the problem of data decoding in media-based modulation systems. The underlying problem is sparse because only a subset of the available transmit antennas is activated in each symbol; additionally, only one of the different mirror patterns is activated depending on the unknown data bits. Thus, the data recovery problem involves recovery of a block-sparse vector, with the additional...
In this paper, we investigate outage performance and diversity gain of transmit antenna selection (TAS) schemes in two-user multiple-input single-output non-orthogonal multiple access (MISO-NOMA) cooperative downlink transmissions. To this end, two TAS criteria, namely Criterion I and Criterion II, are proposed, which select an antenna that experiences the best fading condition of the channel from...
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