scholarly journals On the Degrees of Freedom of Interference Alignment for Multicell MIMO Interfering Broadcast Channels

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Hyun-Ho Choi
Keyword(s):  
Degrees Of Freedom ◽  
Multiple Input Multiple Output ◽  
Interference Alignment ◽  
Dimensional Subspace ◽  
Broadcast Channels ◽  
Transmit Beamforming ◽  
Optimal Dimension ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Multicell Mimo

The interference alignment (IA) is a promising technique to efficiently mitigate interference and to enhance capacity of a wireless network. This paper proposes an interference alignment scheme for a cellular network withLcells andKusers under a multiple-input multiple-output (MIMO) Gaussian interfering broadcast channel (IFBC) scenario. The proposed IA scheme aligns intercell interferences (ICI) into a small dimensional subspace through a cooperative receive beamforming and cancels both the ICI and interuser interferences (IUI) simultaneously through a transmit beamforming. We characterize the feasibility condition for the proposed IA to achieve a total number of degrees of freedom (DoF) ofLKin terms of the numbers of transmit antennas and receive antennas. Then we derive the maximum number of DoF achieved by the proposed IA by finding an optimal dimension of ICI alignment subspace for a given antenna configuration. The numerical results show that the proposed IA scheme has a better DoF performance than the conventional schemes.

The Degrees of Freedom for MIMO Interference Broadcast Channels with no CSIT

2014 ◽  
Vol 1049-1050 ◽  
pp. 1776-1780
Author(s):  
Hai Ying Ren ◽  
Yuan An Liu ◽  
Fang Liu ◽  
Jin Chun Gao ◽  
Kai Ming Liu ◽  
...  
Keyword(s):  
Upper Bound ◽  
Degrees Of Freedom ◽  
Multiple Input Multiple Output ◽  
Broadcast Channels ◽  
Channel State ◽  
State Information ◽  
Perfect Channel State Information ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Channel Information

Multiple-input multiple-output (MIMO) interference broadcast channel (IBC) plays an important role in the modern wireless communications. The upper bound of degree of freedom (DoF) and corresponding achievable schemes have been investigated. However, all the achievable schemes require perfect channel state information at transmitters (CSIT). In the absence of CSIT, the DoF value is still unknown. This paper mainly focuses on theG-cellK-user MIMO IBC, where there areMantennas at each transmitter andNantennas at each receiver. The transmitters only know channel coherent time internals rather than the values of channel coefficients. The users in the same cell are assumed to be able to share the channel information. Based on a heterogeneous block fading model, a blind interference alignment (IA) scheme is proposed for this scenario. We show that when and , then a total of degrees of freedom (DoF) can be achieved. The inner bound is same with the decomposition DoF upper bound.

Rudder/Fin Roll Stabilization of the USCG WMEC 901 Class Vessel

1999 ◽  
Vol 36 (03) ◽  
pp. 157-170
Author(s):  
Jerrold N. Sgobbo ◽  
Michael G. Parsons
Keyword(s):  
Degrees Of Freedom ◽  
Multiple Input Multiple Output ◽  
Cross Coupling ◽  
Degree Of Freedom ◽  
Rolling Motion ◽  
Rolling Moment ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Three Degree Of Freedom ◽  
The U.S

The U.S. Coast Guard's 270-ft Medium Endurance Cutter (WMEC) operates with an active fin stabilization system. This system was designed using a one-degree-of-freedom (1-DOF) model in the roll direction. The controller was designed separate from the heading autopilot. The effects of the rudders and their ability to produce a significant rolling moment were also neglected as well as the cross coupling of roll motions into other degrees of freedom. This paper studies the effects of the rudders on the rolling motion of the ship using a three-degree-of-freedom (3-DOF) model. A simple optimal heading autopilot is designed and combined with the existing fin roll controller to investigate the effects of the rudders on the roll motions of this class of vessel. A rudder roll controller and a multiple input-multiple output (MIMO) rudder/fin controller are designed as well. Significant roll reduction can be achieved using the MIMO rudder/fin controller.

scholarly journals Efficient Wireless Broadcasting through Joint Network Coding and Beamforming

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Monchai Lertsutthiwong ◽  
Thinh Nguyen ◽  
Bechir Hamdaoui
Keyword(s):  
Network Coding ◽  
Multiple Input Multiple Output ◽  
Base Station ◽  
Broadcast Channels ◽  
Achievable Throughput ◽  
Transmission Opportunity ◽  
Mobile Stations ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Multiple Transmit

We develop a framework that exploits network coding (NC) and multiple-input/multiple-output (MIMO) techniques, jointly together, to improve throughput of downlink broadcast channels. Specifically, we consider a base station (BS) equipped with multiple transmit antennas that serves multiple mobile stations (MSs) simultaneously by generating multiple signal beams. Given the large number of MSs and the small number of transmit antennas, the BS must decide, at any transmission opportunity, which group of MSs it should transmit packets to, in order to maximize the overall throughput. We propose two algorithms for grouping MSs that take advantage of NC and the orthogonality of user channels to improve the overall throughput. Our results indicate that the proposed techniques increase the achievable throughput significantly, especially in highly lossy environments.

scholarly journals A novel method for joint- PAPR mitigation in OFDM-based massive MIMO downlink systems

2018 ◽  
Vol 7 (3) ◽  
pp. 1185 ◽  
Author(s):  
Padarti Vijaya Kumar ◽  
Venkateswara Rao Nandanavanam
Keyword(s):  
Massive Mimo ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Multiple Input Multiple Output ◽  
Average Power ◽  
Data Communication ◽  
Multiple Input ◽  
Input Multiple Output ◽  
High Speed Data ◽  
Mimo Downlink

Massive MIMO has gained much attention with the increase in the high speed data communication. The problem of peak-to-average power ratio (PAPR) is considered, the detrimental aspects in OFDM based massive multiple-input multiple-output (MIMO) downlink systems. The previous works done in reduction of PAPR problem using convex optimization are computationally inefficient. We considered Bayesian approach to mitigate PAPR by utilizing the redundant degrees of freedom (DOF) of the transmit array, which effectively reduced the level of PAPR. The performance or numerical results indicate the applied algorithm achieved a good improvement over the existing techniques in terms of the PAPR reduction.  

scholarly journals MIMO Antenna Array Design with Polynomial Factorization

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Wen-Qin Wang ◽  
Huaizong Shao ◽  
Jingye Cai
Keyword(s):  
Antenna Array ◽  
Degrees Of Freedom ◽  
Multiple Input Multiple Output ◽  
Factorization Method ◽  
Polynomial Factorization ◽  
Mimo Antenna ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Simulation Results ◽  
Array Performance

One of the main advantages of multiple-input multiple-output (MIMO) antenna is that the degrees-of-freedom can be significantly increased by the concept of virtual antenna array, and thus the MIMO antenna array should be carefully designed to fully utilize the virtual antenna array. In this paper, we design the MIMO antenna array with the polynomial factorization method. For a desired virtual antenna array, the polynomial factorization method can optimally design the specified MIMO transmitter and receiver. The array performance is examined by analyzing the degrees-of-freedom and statistical output signal-to-interference-plus-noise ratio (SINR) performance. Design examples and simulation results are provided.

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