During recent years, the world is experiencing almost an exponential growth in the demand for various mobile communication services. On the other hand, the available bandwidth for such communication is very much limit...
ISBN:
(纸本)354000355X
During recent years, the world is experiencing almost an exponential growth in the demand for various mobile communication services. On the other hand, the available bandwidth for such communication is very much limited. As a result, efficient utilization of bandwidth for mobile communication has become more and more critical. When a mobile cellular network is designed, each cell of the network is assigned a set of channels to provide services to the individual calls of the cell. The task of assigning frequency channels to the cells satisfying some frequency separation constraints with a view to avoiding channel interference and using as small bandwidth as possible is known as the channel assignment problem. Three types of interference are generally taken into consideration in the form of constraints: i) co-channel constraint, due to which the same channel is not allowed to be assigned to certain pairs of cells simultaneously, ii) adjacent channel constraint, for which adjacent channels are not allowed to be assigned to certain pairs of cells simultaneously, and iii) co-site constraint, which implies that any pair of channels assigned to the same cell must be separated by a certain number. In its most general form, the channel assignment problem (CAP) is equivalent to the generalized graph-coloring problem which is a well-known NPcomplete problem.
This paper deals with the channel assignment problem (CAP) in a hexagonal cellular network with 2-band buffering, where the interference does not extend beyond two cells. Here, we first present new lower bounds on the...
详细信息
This paper deals with the channel assignment problem (CAP) in a hexagonal cellular network with 2-band buffering, where the interference does not extend beyond two cells. Here, we first present new lower bounds on the required bandwidth for a cellular network with homogeneous demand /spl omega/, for various relative values of s/sub 0/, s/sub 1/, and s/sub 2/, the minimum frequency separations required to avoid interference for calls in the same cell, or in cells at distances one and two respectively, where s/sub 0//spl ges/s/sub 1//spl ges/s/sub 2/. Next we present some novel strategies for assigning channels to the cells of the entire cellular network with a homogeneous demand w using a genetic algorithm. We then show how these strategies for homogeneous demand can be extended to the cases with nonhomogeneous demand vector W=(w/sub i/), where w/sub i/ represents the channel requirement for cell i. Most interestingly, it shows that in some cases depending on s/sub 0/, s/sub 1/ and s/sub 2/ the required bandwidth is mainly determined by the maximum demand w/sub max/ in W. It shows that in terms of bandwidth requirement the case is almost equivalent with cellular networks having homogeneous demand w/sub max/. The technique also results optimal bandwidth solutions for all the eight well-known benchmark instances including the most difficult two.
This paper focuses on the important issue of strategies for tracking users in a mobile communication network. Since the users are mobile, the network must keep track of where the users are, a prerequisite for routing ...
详细信息
This paper focuses on the important issue of strategies for tracking users in a mobile communication network. Since the users are mobile, the network must keep track of where the users are, a prerequisite for routing calls to the users. We assume that the mobile users periodically inform the network of their present location. Now, it is very important to decide an efficient location updation strategy that will optimize the overhead in terms of usage of radio spectrum and power, as well as the search cost for a mobile when a call is to be set up. Static location updation strategies often result in poor performance. Three dynamic location updation strategies have been considered, namely, the time-based strategy, the movement-based strategy and the distance-based strategy. A memoryless movement pattern on a two-dimensional mesh topology of cells has been studied. Analytical models have been developed to compare the performance of the strategies. Simulation studies also have been made for performance evaluation.
A unified approach is proposed for performance analysis of an N × M shared-memory multiprocessor system, consisting of N processors and M memory modules, each of which may be ‘hot’ and/or ‘favorite’. Processo...
详细信息
In this paper, we present a new approach to MCM routing to minimize the number of vias and wire length. A 3D routing substrate is partitioned into a number of layers. Chip blocks are placed on the top layer, and routi...
详细信息
In this paper, we present a new approach to MCM routing to minimize the number of vias and wire length. A 3D routing substrate is partitioned into a number of layers. Chip blocks are placed on the top layer, and routing layers are used pair-wise for interconnections. The set of projected pins of the blocks on a routing layer plays the role of obstacles; the space (river) between two consecutive rows/columns of blocks is used for routing. The proposed algorithm consists of a preprocessing stage that determines a routing order among the nets. For each net, a rectilinear Steiner tree with a minimum number of bends is constructed, and the nets are ordered on the basis of a metric called average path length. Next, routing is done in the nonoverlap model, using a heuristic guided by the above ordering. Finally, via minimization is achieved by slightly re-routing the nets in the overlap model. Experimental evidence on standard benchmarks reveals that our solution produces significantly fewer number of vias, and compares favourably with respect to wire length against the best known existing results.
A novel design of a test pattern generator (TPG) for built-in self-testing (BIST) of path delay faults, is proposed. For an n-input CUT, the TPG generates a sequence of length (n.2/sup n/+1), that includes all n.2/sup...
详细信息
A novel design of a test pattern generator (TPG) for built-in self-testing (BIST) of path delay faults, is proposed. For an n-input CUT, the TPG generates a sequence of length (n.2/sup n/+1), that includes all n.2/sup n/ single-input-change (SIC) test pairs, and hence optimal. The generation of such a sequence of minimum length (i.e., n.2/sup n/+1) was an open problem. A simple iterative circuit of the TPG is then constructed. This provides minimum test application time for testing path delay faults, and compares favorably with the earlier BIST designs.
New techniques are presented for routing L-shaped channels, switchboxes and staircases in 2-layer Manhattan-diagonal (MD) model with tracks in horizontal, vertical and /spl plusmn/45/spl deg/ directions. First, a simp...
详细信息
New techniques are presented for routing L-shaped channels, switchboxes and staircases in 2-layer Manhattan-diagonal (MD) model with tracks in horizontal, vertical and /spl plusmn/45/spl deg/ directions. First, a simple O(l.d) time algorithm is proposed which routes any L-shaped channel with length l, density d and no cyclic vertical constraints, in w (d/spl les/w/spl les/d+1) tracks. Next, an O(l.w) time greedy method for routing an L-shaped channel with cyclic vertical constraints, is described. Then, the switchbox routing problem in the MD model is solved elegantly. These techniques, easily extendible to the routing of staircase channels, yield efficient solutions to detailed routing in general floorplans. Experimental results show significantly low via-count and reduced wire length, thus establishing the superiority of MD-routing over classical strategies.
This book constitutes the proceedings of the First Indo-Japanese conference on Perception and Machine Intelligence, PerMIn 2012, held in Kolkata, India, in January 2012. The 41 papers, presented together with 1 keynot...
详细信息
ISBN:
(数字)9783642273872
ISBN:
(纸本)9783642273865
This book constitutes the proceedings of the First Indo-Japanese conference on Perception and Machine Intelligence, PerMIn 2012, held in Kolkata, India, in January 2012.
The 41 papers, presented together with 1 keynote paper and 3 plenary papers, were carefully reviewed and selected for inclusion in the book. The papers are organized in topical sections named perception; human-computer interaction; e-nose and e-tongue; machine intelligence and application; image and video processing; and speech and signal processing.
暂无评论