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This paper proposes a new type of fiber-optic relaying that extends the coverage of mobile networks. The antenna facing the evolved Node B (eNB) is geographically separated from the antenna facing the user equipment, and the two antennas are connected by an optical fiber. This paper presents a practical design method for fiber-optic inband relaying in the presence of self-interference, which is the...
This paper presents optimum transmission strategies in terms of the number of transmission antennas and pilot symbols for secondary users of multiple-input and multiple-output system. By complying with the restriction of transmission power from geo-location database, secondary users can protect primary users. However, the receiver of secondary users can suffer from the interference by primary users...
In this paper, we propose an alignment-based interference cancellation scheme for a multi-cell network with interfering multiple-input multiple-output (MIMO) users. The proposed technique targets two prevailing sources of interference through an appropriately designed beamforming matrix. It will be shown that using this method allows one to convert the multi-cell MIMO channel into a single-cell MIMO...
Interference is known to cause the performance degradation of the wireless network. To solve the interference problem, cooperative transmission scheme such as interference alignment (IA) is required. Channel state information (CSI) among IA participation nodes should be essentially obtained to implement IA. By implementing the IA prototype with obtaining the real environment CSI, we can check the...
Radar performance can be downgraded when facing interference. One of external interference is another radar placed in the nearby location which behaves as a jammer affecting the radar maximum detection by decreasing the signal to noise ratio (SNR) level. This paper describes the effect of external radar as a source of jammer in the main-radar performance. This can be occurred when multiple radars...
As part of ONR's Integrated Topside (InTop) Program, in 2014 Northrop Grumman delivered a bi-static, active, electronic scanned array (AESA) system, capable of multifunction, simultaneous transmit and receive operation. The system is wide band, transmits high power and has high receive sensitivity. Further, there are simultaneous transmit and receive modes required, in which the transmit AESA radiates...
We consider the two-user multiple-input multiple-output X-channel where the transmitters 1, 2 have M1,M2 antennas and the receivers 1, 2 have N1,N2 antennas, respectively, and study the achievable number of degrees of freedom (DoF) of this network under the assumption of delayed channel state information at the transmitters. For this scenario, Kao and Avestimehr proposed in [1] a transmission scheme,...
The present work focuses on the forward link of fixed multibeam broadband satellite systems which employ aggressive frequency reuse patterns in the user-link. For such scenarios, the state-of-the art frame based precoding methods can improve the system performance, exploiting the super framing structure of the latest physical layer evolutions in satellite communications. Nevertheless, the limitations...
This paper tackles the problem of multi-user in- terference in the forward downlink channel of a multi-beam satellite system. A symbol-level precoding scheme is considered, where the data information is used, along with the channel state information, in order to exploit the multi-user interference and transform it into useful power at the receiver side. In this frame- work, the max-min fair problem...
Blind Interference Alignment (BIA) can greatly improve channel capacity through simultaneous transmitting multiple encoded data streams (EDSs), but can also result in low power efficiency, especially in the multi-network scenario. To address such problem, this paper takes the first step in this direction and presents paired-user BIA in a two-cell network, where users form pairs performing BIA improving...
This paper investigates a multi-pair two-way massive MIMO amplify-and-forward full-duplex relay (MM-AFFDR) system over Ricean fading channels, where multiple pairs of full-duplex users exchange information within pair through a full-duplex relay with very large number of antennas (M for transmission and M for reception). Firstly, the zero-forcing reception/zero-forcing transmission (ZFR/ZFT) processing...
We present a transmit antenna subset selection scheme for an underlay cognitive system serving multiple secondary receivers. The secondary system employs zero-forcing beamforming to nullify the interference to multiple primary users and eliminate inter-user interference to the secondary users simultaneously. Simulation results show that the proposed scheme achieves near-optimal performance with low...
The overlaid cell structure, in which a large number of small cells are deployed in a macro-cell coverage area, is considered to be a promising approach in order to accommodate rapidly increasing mobile data traffic. In the overlaid cell structure, eICIC (enhanced Inter-Cell Interference Coordination) is an essential technique to avoid the interference between the macro cells and the small cells when...
We propose a transmit preprocessing aided spatial modulation (PSM) scheme for downlink of multi-user multiple-input multiple-output (MIMO) systems which exploits the spatial correlation matrices of users. In this way, array antennas in base station can be scaled to large dimensions while requiring reduced dimension channel state information at transmitter (CSIT). This property makes proposed PSM suitable...
Channel state information at the transmitter affects the degrees of freedom of the wireless networks. In this paper, we analyze the DoF for the K-user multiple-input single-output (MISO) broadcast channel (BC) with synergistic alternating channel state information at the transmitter (CSIT). Specifically, the CSIT of each user alternates between three states, namely, perfect CSIT (P), delayed CSIT...
In the high-data transmission system, the polarization multiplexing technique is a robust way to enhance the spectrum efficiency. Due to the adverse weather and imperfections of equipments, cross-polarization interference and co-polarization attenuation have been introduced. Thus, cross-polarization interference canceller (XPIC) must be adopted to guarantee the communication QOS and reliability. In...
First, the paper analyzes the basic principle of the uplink MU-MIMO and gives the user matching conditions and application suggestion. Then, an estimation method of uplink MU-MIMO gain is presented based on the tests analysis. At last, the performance of uplink MU-MIMO in the current user condition is also given.
In Cognitive radio networks the performance of secondary users depends on the co-channel interference generated by both primary and secondary users. A transmit antenna selection (TAS) technique which increases the capacity of secondary user with less hardware has been dealt in literature for CRN. The subset of antenna was selected with the assumption that the secondary transmitter works under the...
Massive Multi Input and Multi Output (M-MIMO) is the most prominent technology to improve the spectral and energy efficiency of future wireless systems by deploying multiple number of antennas at the base station. In this letter, we considered the impact of spatially correlation on massive MIMO downlink systems with achievable data rate in the block fading environment. The proposed schemes exploit...
Maximizing the total information rates of downlink coordinated multi-point (CoMP) transmission without zero-forcing (ZF) constraints is investigated. ZF can simplify the CoMP transmission problem, but the number of serviced users is limited by the number of antennas of all the coordinated base stations (BS). Without ZF constraints, more users can be serviced at the same time. In order to solve the...
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