Channel State Information

Mobile communication on the multi-beam satellite communication has attracted attention, since  Digital Video Broadcasting – Return Channel Satellite (DVB-RCS) has been successively implemented.  In general, multi beam satellite employs uniform allocation of RF power and bandwidth to multi beams, since it is hard to predict the distribution of traffic requests and the arrival rate of new connection. This makes it difficult to satisfy the traffic requests in a beam. Thus, when an unpredictable event, such as a disaster, regional warfare and deteriorating weather conditions, occur in a special spot beam, many more terminals will require access to a special beam channel. This causes the special beam channel to be saturated, while adjacent beam channel resources are available. Thus, we propose a novel handover strategy to improve satellite return link resource utilization using load balancing handover. Simulation results shows the proposed handover algorithm outperforms conventional handover algorithms in terms of new connection block probability, handover block probability, return link resource utilization and capacity request block rate.

We investigate the capacity of a multiple access channel with cooperating encoders where partial state information is known to each encoder and full state information is known to the decoder. The cooperation between the encoders has a two-fold purpose: to generate empirical state coordination between the encoders, and to share information about the private messages that each encoder has. For two-way cooperation, this two-fold purpose is achieved by double-binning, where the first layer of binning is used to generate the state coordination similarly to the two-way source coding, and the second layer of binning is used to transmit information about the private messages. The complete result provides the framework and perspective for addressing a complex level of cooperation that mixes states and messages in an optimal way.

We consider the problem of differentiated rate scheduling for the fading MIMO Gaus- sian broadcast channel, in the sense that the rates required by different users must satisfy certain rational rate constraints. When full channel state information (CSI) is available at the transmitter, the problem can be readily solved using dirty paper coding (DPC) and con- vex optimization techniques on

Massive MIMO is the emerging technology to design 5G wireless communication systems. Perfect channel state information(CSI) is the essential condition to design the performance metrics for MU-MIMO system since the inaccuracies present in the CSI reduces data rates and channel capacity. The objective of this paper is to design a optimum power allocation scheme for MU-MIMO using dirty paper coder precoding. An expression is derived to determine the optimum power allocation and the ambient condition with degree of perfection factor under channel reliability at the base station to reduce the transmit power and the results obtained are presented and analysed. 2018 The Korean Institute of Communications and Information Sciences. Publishing Services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

In this paper, we study uplink-downlink non-orthogonal multiple access (NOMA) systems by considering the secure performance at the physical layer. In the considered system model, the base station acts a relay to allow two users at the left side communicate with two users at the right side. By considering imperfect channel state information (CSI), the secure performance need be studied since an eavesdropper wants to overhear signals processed at the downlink. To provide secure performance metric, we derive exact expressions of secrecy outage probability (SOP) and and evaluating the impacts of main parameters on SOP metric. The important finding is that we can achieve the higher secrecy performance at high signal to noise ratio (SNR). Moreover, the numerical results demonstrate that the SOP tends to a constant at high SNR. Finally, our results show that the power allocation factors, target rates are main factors affecting to the secrecy performance of considered uplink-downlink NOMA systems. This is an open access article under the CC BY-SA license.

In this paper, we focus on a cellular system with M transmit antennas at the base station (BTS) and one receive antenna at the mobile (i.e. an M -input/single-output (MISO) channel), where the BTS commands each mobile to transmit its channel state information back to the BTS. Our main result is a specific feedback scheme with adaptive bit allocation, where

Zero-forcing (ZF) beamforming, an efficient technique for multiuser MIMO systems, requires perfect channel state information to be available at the base station. This is achieved by quantizing the channel and feeding back the information with a limited number of bits. A challenge of this method is the large downlink signaling overhead, which is due to the large size of the

Massive MIMO is the emerging technology to design 5G wireless communication systems. Perfect channel state information(CSI) is the essential condition to design the performance metrics for MU-MIMO system since the inaccuracies present in the CSI reduces data rates and channel capacity. The objective of this paper is to design a optimum power allocation scheme for MU-MIMO using dirty paper coder precoding. An expression is derived to determine the optimum power allocation and the ambient condition with degree of perfection factor under channel reliability at the base station to reduce the transmit power and the results obtained are presented and analysed. 2018 The Korean Institute of Communications and Information Sciences. Publishing Services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

We characterize the total weighted squared correlation (TWSC) used in uplink synchronous code division multiple access (S-CDMA) as a payoff function in the context of the game theoretic framework. We proved that the value of the game for two players is a saddle-point corresponding to the minimum of TWSC. The optimal solution is the Stackelberg equilibrium and is achieved by players choosing generalized Welch bound equality (WBE) sequences as spreading signatures. We propose an algorithm of minimizing TWSC in the presence of multipath and colored noise when channel state information is known perfectly at both transmitter and receiver. A comparison of our method in terms of BER (bit error rate) and water-filling procedure with the previous known methods is also given.

ABSTRACT In this paper, equalization for transmission over doubly selective channels is discussed. The symbol-by-symbol maximum a posteriori probability (MAP) equalizer and the maximum-likelihood sequence estimation (MLSE) are discussed. The doubly selective channel is modeled using the basis expansion model (BEM). Using the BEM allows for an easy and low-complexity mechanism for constructing the channel trellis to implement the MLSE and the MAP equalizer. The MLSE and the MAP equalizer are implemented for single-carrier transmission and for multicarrier transmission implemented using orthogonal frequency-division multiplexing (OFDM). In this scenario, a complexity-diversity tradeoff can be observed. In addition, we propose a joint estimation and equalization technique for doubly selective channels. In this joint estimation and equalization technique, the channel state information (CSI) is obtained in an iterative manner. Simulation results show that the performance of the joint channel estimation and equalization approaches the performance when perfect CSI is available at the receiver.

Interference between nodes is a critical impairment in mobile ad hoc networks. This paper studies the role of multiple antennas in mitigating such interference. Specifically, a network is studied in which receivers apply zero-forcing beamforming to cancel the strongest interferers. Assuming a network with Poisson-distributed transmitters and independent Rayleigh fading channels, the transmission capacity is derived, which gives the maximum