arXiv subjects

Guoqiang Zhang

Publications and source records attributed to Guoqiang Zhang.

76 records · Page 5Linked to original sources

arXiv2010

Bounding the Rate Region of Vector Gaussian Multiple Descriptions with Individual and Central Receivers

In this work, the rate region of the vector Gaussian multiple description problem with individual and central quadratic distortion constraints is studied. In particular, an outer bound to the rate region of the L-description problem is derived. The bound is obtained by lower bounding a weighted sum rate for each supporting hyperplane of the rate region. The key idea is to introduce at most L-1 auxiliary random variables and further impose upon the variables a Markov structure according to the ordering of the description weights. This makes it possible to greatly simplify the derivation of the outer bound. In the scalar Gaussian case, the complete rate region is fully characterized by showing that the outer bound is tight. In this case, the optimal weighted sum rate for each supporting hyperplane is obtained by solving a single maximization problem. This contrasts with existing results, which require solving a min-max optimization problem.

cs.IT↗

arXiv2010

On cost-effective communication network designing

How to efficiently design a communication network is a paramount task for network designing and engineering. It is, however, not a single objective optimization process as perceived by most previous researches, i.e., to maximize its transmission capacity, but a multi-objective optimization process, with lowering its cost to be another important objective. These two objectives are often contradictive in that optimizing one objective may deteriorate the other. After a deep investigation of the impact that network topology, node capability scheme and routing algorithm as well as their interplays have on the two objectives, this letter presents a systematic approach to achieve a cost-effective design by carefully choosing the three designing aspects. Only when routing algorithm and node capability scheme are elegantly chosen can BA-like scale-free networks have the potential of achieving good tradeoff between the two objectives. Random networks, on the other hand, have the built-in character for a cost-effective design, especially when other aspects cannot be determined beforehand.

cs.NI↗

arXiv2009

A scientific understanding of network designing

As the Internet becomes severely overburdened with exponentially growing traffic demand, it becomes a general belief that a new generation data network is in urgent need today. However, standing at this crossroad, we find that we are in a situation that lacks a theory of network designing. This issue becomes even more serious as the recent progress of network measurement and modeling challenges the foundation of network research in the past decades. This paper tries to set up a scientific foundation for network designing by formalizing it as a multi-objective optimization process and quantifying the way different designing choices independently and collectively influence these objectives. A cartesian coordinate system is introduced to map the effect of each designing scheme to a coordinate. We investigated the achievable area of the network designing space and proved some boundary conditions. It is shown that different kind of networks display different shapes of achievable areas in the cartesian coordinate and exhibit different abilities to achieve cost-effective and scalable designing. In particular, we found that the philosophy underlying current empirical network designing and engineering fails to meet the cost-effective and evolvable requirements of network designing. We demonstrated that the efficient routing combined with effective betweenness based link bandwidth allocation scheme is a cost-effective and scalable design for BA-like scale-free networks, whereas if other designing choices cannot be determined beforehand, ER network is a markedly good candidate for cost-effective and scalable design.

cs.NI↗

arXiv2009

Enhancing network transmission capacity by efficiently allocating node capability

A network's transmission capacity is the maximal rate of traffic inflow that the network can handle without causing congestion. Here we study how to enhance this quantity by redistributing the capability of individual nodes while preserving the total sum of node capability. We propose a practical and effective node-capability allocation scheme which allocates a node's capability based on the local knowledge of the node's connectivity. We show the scheme enhances the transmission capacity by two orders of magnitude for networks with heterogenous structures.

cs.NI↗