Hot-spot Cell Research Articles

Layout-Driven Post-Placement Techniques for Temperature Reduction and Thermal Gradient Minimization

With the continuing scaling of CMOS technology, on-chip temperature and thermal-induced variations have become a major design concern. To effectively limit the high temperature in a chip equipped with a cost-effective cooling system, thermal specific approaches, besides low power techniques, are necessary at the chip design level. The high temperature in hotspots and large thermal gradients are caused by the high local power density and the nonuniform power dissipation across the chip. With the objective of reducing power density in hotspots, we propose two placement techniques that spread cells in hotspots over a larger area. Increasing the area occupied by the hotspot directly reduces its power density, leading to a reduction in peak temperature and thermal gradient. To minimize the introduced overhead in delay and dynamic power, we maintain the relative positions of the coupling cells in the new layout. We compare the proposed methods in terms of temperature reduction, timing, and area overhead to the baseline method, which enlarges the circuit area uniformly. The experimental results showed that our methods achieve a larger reduction in both peak temperature and thermal gradient than the baseline method. The baseline method, although reducing peak temperature in most cases, has little impact on thermal gradient.

Realistic Energy Saving Potential of Sleep Mode for Existing and Future Mobile Networks

This paper presents an extensive overview on an energy saving feature referred to as ‘site sleep mode’, designed for existing and future mobile broadband networks. In addition to providing a detailed understanding of the main concept, the paper also provides various studies and results to highlight potential savings, and emphasize some of the expected limitations. Since site measurements show that the energy consumption of base station sites is largely load-independent, this makes such a feature highly effective for reducing the energy consumption of mobile networks during hours of low traffic. After going through a number of different alternatives of the feature, this is applied to different network topologies, macro-only based networks, and a set of heterogeneous networks that employ the use of small cells in traffic hotspots. Results obtained through detailed case studies show that sleep mode can reduce the average daily energy consumption of a network by around 30%. This can be achieved while maintaining a predefined level of performance, used as a measure of comparing different scenarios.

First appearance and location of catecholaminergic cells during experimental arthritis and elimination by chemical sympathectomy

The sympathetic nervous system is proinflammatory in early collagen-induced arthritis (CIA) and antiinflammatory in late disease. In late arthritis, sympathetic innervation of synovial and lymphoid tissue is markedly reduced. Thus, its suggested antiinflammatory role is difficult to explain. We hypothesized that newly discovered catecholamine-producing (catecholaminergic) cells are targets of chemical sympathectomy. However, in CIA, the time point of appearance, the location, and the possible chemical elimination of catecholaminergic cells have not been studied. The purpose of this study was to investigate the emergence and location of catecholamine-producing and -storing cells in different organs and joints of mice after induction of CIA and to determine whether catecholamine-producing cells can be depleted by 6-hydroxydopamine (6-OHDA) during the early and late phases of CIA in vivo. The presence of cells positive for tyrosine hydroxylase (TH) and vesicular monoamine transporter 2 (VMAT-2) was evaluated immunohistologically in the lymph nodes, thymus, bone marrow, spleen, and joints of control and arthritic mice. Density was evaluated at different time points after early and late chemical sympathectomy. (131)I-metaiodobenzylguanidine ((131)I-MIBG) scintigraphy demonstrated functional activity of these cells in joint inflammation. The density of TH+ and VMAT-2+ cells was highest after arthritis onset (from day 28 onward) and was observed to occur in the following sequence: lymph nodes, thymus, joints, bone marrow, and spleen. Even before arthritis onset (days 5-21), these cells were already more numerous, particularly in the draining lymph nodes, thymus, and joints. (131)I-MIBG scintigraphy demonstrated catecholamine-storing cells in inflammatory hot spots in the paw. Chemical sympathectomy strongly reduced the density of catecholaminergic cells in vitro and in vivo. After disease onset, catecholaminergic cells are particularly present in primary and secondary lymphoid organs and joints. Since catecholaminergic cells have been reported to have antiinflammatory properties in arthritis, the proinflammatory role played by chemical sympathectomy in late arthritis, as we previously determined, is probably dependent on catecholaminergic cell elimination.

Non-congruence among hotspots based on three common diversity measures in Yunnan, south-west China

Background: Yunnan is one of the richest regions of the world in terms of plant diversity. As a result of increasing pressure from land use, it is in need of identifying priority areas for conservation. Aim: In this study, we aimed to identify hotspots for plant conservation based on different measures of diversity and to establish the degree of spatial congruence among the different measures of diversity. Methods: We compiled checklists of overall species richness, threatened species and plants endemic to Yunnan with the help of literature and experts. The values of these three measures were grid mapped and the highest 2.5% of all cells with respect to each of the three plant diversity measures were designated as hotspot cells. The grid maps were overlapped to examine the spatial congruence of three different types of hotspots. Diversity measures were related to climatic and geographical factors. Finally, a gap analysis was carried out to examine the relationship between the location of existing nature reserves and the identified hotspots. Results: The hotspots of endemic plants and those of overall species richness were mostly concentrated in north-west Yunnan, whereas those of threatened plants were mainly observed in south Yunnan. No congruence was observed across the three types of hotspots of plant diversity at the top 2.5% cut-off level. With the relaxation of the cut-off level, an increasing trend of congruence could be observed, indicated by a strong correlation between measures of diversity. No strong relationship was found between climatic and geographical factors, and values of diversity measures. The gap analysis showed that there were some nature reserves located within or in the proximity of each identified hotspot. Conclusions: We suggest that non-congruence across different types of hotspots highlights the importance of cut-off levels for hotspot selection for congruence across different types of hotspots. Different mechanisms may be responsible for the spatial patterns of species diversity of total richness, endemic plants, threatened plants and the hotspots of the three diversity measures. Climatic and geographical factors cannot satisfactorily explain spatial patterns of plant diversity over the whole study area because controlling factors differ in geographical dimensions. Conservation strategy should also be different for different parts of Yunnan. In north-west Yunnan (hotspots of overall richness and endemism), attention needs to be focused on the protection and maintenance of diverse habitats, whereas in south Yunnan (hotspots of threatened plants) conservation strategies should concentrate on the restoration of habitats and off-site conservation.

804 IL-17 EXPRESSED LEUKOCYTES ARE CHARACTERISTIC OF PROSTATE INFLAMMATORY ATROPHY LESIONS IN PATIENTS WITH PROSTATE CANCER

You have accessJournal of UrologyInfections/Inflammation of the Genitourinary Tract: Prostate & Genitalia1 Apr 2010804 IL-17 EXPRESSED LEUKOCYTES ARE CHARACTERISTIC OF PROSTATE INFLAMMATORY ATROPHY LESIONS IN PATIENTS WITH PROSTATE CANCER Eugene Vykhovanets, Gregory MacLennan, Olena Vykhovanets, and Sanjay Gupta Eugene VykhovanetsEugene Vykhovanets More articles by this author , Gregory MacLennanGregory MacLennan More articles by this author , Olena VykhovanetsOlena Vykhovanets More articles by this author , and Sanjay GuptaSanjay Gupta More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.1480AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES The phenotype of intraprostatic mononuclear cells (MNC) is still illusive, despite their role for chronic inflammation and prostate cancer (PCa). Expression of interleukin (IL)-17 is a characteristic of a CD4 T cell subset called T helper 17 (TH17) cells. Their role in host defense and in autoimmunity was recently established. Little is known about other IL-17 expressing cells at sites of tissue inflammation. Based on our previous findings we hypothesized that the IL-17 producing cells may be targets of specific inflammatory signals that initiate inflammation at sites of proliferative inflammatory atrophy (PIA) of the prostate. METHODS To immunophenotype MNC infiltrates we evaluated 30 formalin-fixed paraffin-embedded whole mount radical prostatectomy specimens. Two-color immuno-histochemestry was employed to distinguish macrophages (Mφ), B, T, and CD4 T helper cells. Quantitation of IL-17 cells was performed in all sites of MNC accumulation in the entire prostate, noting their relationships to PCa, PIA, or benign tissue. RESULTS T and B cells were commonly observed at the site of MNC accumulation (“hot spots”). The number of hot spots varied significantly from case to case (mean = 24±12 [SD] per prostate). MNC aggregates were found in and around areas of PCa, and in areas of PIA. The numbers of B and T cells were almost equal within the MNC hot spots. CD4 helper cells were the predominant T cells in the MNC hot spots. Levels of IL-17 cells were similar in zones of benign prostate tissue and areas of PCa. Pronounced intraluminal and peri-glandular IL-17 cell accumulation characterized the MNC infiltrates associated with PIA lesions. The number of IL-17 cells in the intraluminal and peri-glandular areas of PIA lesions was 5 fold higher than in the MNC aggregates within areas of PCa and 5 fold higher than in benign tissue populated by only scattered MNC. The number of IL-17 cells in the intraluminal and peri-glandular areas of PIA lesions was 3 fold higher than in MNC aggregates in benign tissue adjacent to PCa, and 3 fold higher than in randomly situated MNC aggregates in benign prostate tissue. Consecutive slide analysis indicated that glandular and peri-glandular Mφ and neutrophils, rather than TH17 cells, were the predominant IL-17 producing cells in PIA lesions. CONCLUSIONS These data demonstrate that release of inflammatory IL-17 by MNC may be the initiating factor in prostatic PIA. The accumulation of IL-17 producing cells in PIA lesions presents direct evidence of an inflammatory microenvironment that may support the development and progression of PCa. Cleveland, OH© 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e314 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Eugene Vykhovanets More articles by this author Gregory MacLennan More articles by this author Olena Vykhovanets More articles by this author Sanjay Gupta More articles by this author Expand All Advertisement Advertisement PDF DownloadLoading ...

Kernel density estimation and K-means clustering to profile road accident hotspots

Identifying road accident hotspots is a key role in determining effective strategies for the reduction of high density areas of accidents. This paper presents (1) a methodology using Geographical Information Systems (GIS) and Kernel Density Estimation to study the spatial patterns of injury related road accidents in London, UK and (2) a clustering methodology using environmental data and results from the first section in order to create a classification of road accident hotspots. The use of this methodology will be illustrated using the London area in the UK. Road accident data collected by the Metropolitan Police from 1999 to 2003 was used. A kernel density estimation map was created and subsequently disaggregated by cell density to create a basic spatial unit of an accident hotspot. Appended environmental data was then added to the hotspot cells and using K-means clustering, an outcome of similar hotspots was deciphered. Five groups and 15 clusters were created based on collision and attribute data. These clusters are discussed and evaluated according to their robustness and potential uses in road safety campaigning.

Plant Diversity Hotspots in the Atlantic Coastal Forests of Brazil

Plant-diversity hotspots on a global scale are well established, but smaller local hotspots within these must be identified for effective conservation of plants at the global and local scales. We used the distributions of endemic and endemic-threatened species of Myrtaceae to indicate areas of plant diversity and conservation importance within the Atlantic coastal forests (Mata Atlântica) of Brazil. We applied 3 simple, inexpensive geographic information system (GIS) techniques to a herbarium specimen database: predictive species-distribution modeling (Maxent); complementarity analysis (DIVA-GIS); and mapping of herbarium specimen collection locations. We also considered collecting intensity, which is an inherent limitation of use of natural history records for biodiversity studies. Two separate areas of endemism were evident: the Serra do Mar mountain range from Paraná to Rio de Janeiro and the coastal forests of northern Espírito Santo and southern Bahia. We identified 12 areas of approximately 35 km(2) each as priority areas for conservation. These areas had the highest species richness and were highly threatened by urban and agricultural expansion. Observed species occurrences, species occurrences predicted from the model, and results of our complementarity analysis were congruent in identifying those areas with the most endemic species. These areas were then prioritized for conservation importance by comparing ecological data for each.

A Dynamic Channel Assignment Scheme for TDMA-based Multihop Cellular Networks

In this paper, we propose a multihop dynamic channel assignment (MDCA) scheme for time division multiple access (TDMA)-based multihop cellular networks. The proposed MDCA assigns channels to calls based on interference information in surrounding cells, provided by the interference information table (IIT) in the network. Two different channel searching strategies, Sequential channel searching (SCS) and packing-based channel searching (PCS), for use in MDCA are proposed and studied. A channel reassignment procedure to further enhance the performance is also investigated. Simulation results show that MDCA significantly improves the system capacity. Furthermore, the MDCA can efficiently alleviate the call blocking in hot-spot cells.

An effective traffic management scheme using adaptive handover time in next‐generation cellular networks

AbstractNext‐generation cellular networks are expected to support various multimedia services over IP networks with high spectral efficiency. In these networks, hotspot cells can occur when available wireless resources at some location are not sufficient to sustain the needs of users. The hotspot cell can potentially lead to blocked or dropped calls, which can deteriorate the service quality for users. A group of users enjoying multimedia services could move around in the networks generating heavy flows of traffic. This situation can generate a hotspot cell which has a short lifespan of only a few minutes. If there is a steady increase in the number of these users, the hotspot cell which has a short lifespan will occur more frequently in the overall service area. In this paper, we propose a handover‐based traffic management scheme which can effectively deal with hotspot cells in next‐generation cellular networks. With our scheme, the current serving cell can recognize the traffic load status of the target cell in advance, before handover execution. Then, according to the load status, it adaptively controls the handover time. The handover‐based traffic management scheme can effectively and flexibly handle hotspot cells in the networks. Acceptable service quality can also be supported as users continuously maintain communication links. In the simulation results, we find that our scheme generates a smaller number of hotspot cells and supports higher service quality than the schemes compared. Copyright © 2006 John Wiley & Sons, Ltd.

Determination of Optimal Cell Capacity for Initial Cell Planning in Wireless Cellular Networks

In wireless cellular networks, previous researches on admission control policies and resource allocation algorithm considered the QoS (Quality of Service) in terms of CDP (Call Dropping Probability) and CBP (Call Blocking Probability). However, since the QoS was considered only within a predetermined cell capacity, the results indicated a serious overload problem of systems not guaranteeing both CDP and CBP constraints, especially in the hotspot cell. That is why a close interrelationship between CDP, CBP and cell capacity exists. Thus, it is indispensable to consider optimal cell capacity guaranteeing multiple QoS (CDP and CBP) at the time of initial cell planning for networks deployment. In this paper, we will suggest a distributed determination scheme of optimal cell capacity guaranteeing both CDP and CBP from a long-term perspective for initial cell planning. The cell-provisioning scheme is performed by using both the two-dimensional continuous-time Markov chain and an iterative method called the Gauss-Seidel method. Finally, numerical and simulation results will demonstrate that our scheme successfully determines an optimal cell capacity guaranteeing both CDP and CBP constraints for initial cell planning.

Study on Traffic Shedding for Soft-Handoff Using MC-CDMA in Wireless ATM Networks

In wireless ATM mobile communication environments, an abrupt increase in the number of mobile users in a specific base station (BS) will overload the BS and turn it into a so-called hot-spot cell, which causes an unbalanced traffic load condition if the traffic load in the neighboring BSs is light. In order that efficiently allevates to utilize a limited bandwidth, it is necessary to use a good mobile handoff strategy to alleviate unbalanced traffic load condition. This paper proposes a complete traffic shedding algorithm (CTSA) for soft handoff efficiently to alleviate the overloaded traffic in a hot-spot cell by adjusting handoff parameters, which virtually reduces the service coverage of the heavy loaded BS without adjusting the transmission power. Mobile terminals (MT) located in the outer area of the hot-spot cell will be handed off early to the neighboring BSs with light traffic load; and MTs in the neighboring BSs will not be handed off to the hot-spot cell, so that the traffic load of the hot-spot cell can be decreased. After analyzing the proposed algorithm and comparing the other methods, variable threshold soft handoff (VTSH) and enhanced soft handoff (ESH), by simulation, the performance of CTSA is better than the others. CTSA obviously increases system throughput and decreases soft handoff call dropping ratio, new call blocking ratio, and total call refusing ratio.

A Light Call Admission Control with Inter-Cell and Inter-Service Fairness in Heterogeneous Packet Radio Networks

In this paper, we propose a new measurement-based fair call admission control policy for heterogeneous packet radio networks. The objectives of the new admission policy are to 1) reduce computation overhead and rapidly re-allocate resources to keep desired Quality of Service (QoS) demands, 2) relieve hot-spot cell by reducing the number of handoff calls from neighboring cells, 3) fairly admit voice and data traffic to prevent declined service degradation. With numerical analysis, we evaluate QoS constraints and inter-cell as well as inter-service fairness by using queuing model, which is described by a two-dimensional continuous-time Markov chain. Finally, we validate our model's accuracy by comparing results of analytical model with ones of event-driven simulation.

Variable Spreading Factor-OFCDM with Two Dimensional Spreading that Prioritizes Time Domain Spreading for Forward Link Broadband Wireless Access

This paper proposes the optimum design for adaptively controlling the spreading factor in Orthogonal Frequency and Code Division Multiplexing (OFCDM) with two-dimensional spreading according to the cell configuration, channel load, and propagation channel conditions, assuming the adaptive modulation and channel coding (AMC) scheme employing QPSK and 16QAM data modulation. Furthermore, we propose a two-dimensional orthogonal channelization code assignment scheme to achieve skillfully orthogonal multiplexing of multiple physical channels. We first demonstrate the reduction effect of inter-code interference by the proposed two-dimensional orthogonal channelization code assignment. Then, computer simulation results show that in time domain spreading, the optimum spreading factor, except for an extremely high mobility case such as for the fading maximum Doppler frequency of f D = 1500 Hz, becomes SF Time = 16. Furthermore, it should be decreased to SF Time = 8 for such a very fast fading environment using 16QAM data modulation. We also clarify when the channel load is light such as C mux /SF = 0.25 (C mux and SF denote the number of multiplexed codes and total spreading factor, respectively), the required average received signal energy per symbol-to-noise power spectrum density ratio (E s /N 0 ) is reduced as the spreading factor in the frequency domain is increased up to say SF Freq = 32 for QPSK and 16QAM data modulation. When the channel load is close to full such as when C mux /SF = 0.94, the optimum spreading factor in the frequency domain is SF Freq = 1 for 16QAM data modulation and SF Freq = 1 to 8 for QPSK data modulation according to the delay spread. Consequently, by setting several combinations of spreading factors in the time and frequency domains, the near maximum link capacity is achieved both in cellular and hotspot cell configurations assuming various channel conditions.

A New Approach to the Reactive Burn Modeling of Heterogeneous Explosives

This paper discusses a new approach to building mechanistic models for shock ignition and other reactive phenomena in heterogeneous solid explosives. In the proposed approach, hot spots are treated on a unifying framework (a hot-spot cell) to integrate the three, principal response behaviors of heterogeneous energetic materials: energy localization (hot-spot formation), temperature dependent chemical reactions, and heat flow. Hot spots are treated statistically through use of a size distribution and its evolution equation. Chemical reactions start at the surface of hot spots, and the products in turn become reactants for the subsequent bulk reactions. A heat conduction equation is solved for the temperature states in the hot-spot cell. Ignition and growth of the reactive burn depend on the complex interactions of the three processes: localized energy deposition, chemical reactions (surface as well as bulk), and heat flow. Coupling of the hot-spot model to hydrodynamic flow equations is based at present on a single cell, using mass averaged mixture equations of state and a common particle velocity for the constituents. The overall model is implemented on a two-dimensional Lagrangian code called CASH. To demonstrate the predictive capability of the model, we show several exploratory calculations using RDX as a model material.more » They include (1) shock ignition and growth-to-detonation, (2) quenching, and (3) curved detonation in a cylindrical specimen.« less

Capacity Gain of Beamforming Techniques in a WCDMA System Under Channelization Code Constraints

This study addresses the performance of a wideband code-division multiple-access mobile communications system with beamforming antenna arrays (AAs) at the base station, synthesizing a grid of beams. In order to fully exploit the capacity gain from beamforming without jeopardizing the stability of the system, a directional power-based admission control (AC) scheme is applied. Due to the higher capacity offered by beamforming techniques, shortage of orthogonal channelization codes in the downlink becomes an increasingly important factor, which may result in blocking of users before the interference power limit is reached. The problem of channelization code shortage is addressed, and a solution based on splitting the cell into several code regions is proposed. For a network with circuit switched data services operated at 64 kb/s, the capacity gain for an eight-element AA is found to equal a factor of 2.5 for a universal mobile telecommunications equivalent system, with one channelization code set per cell. The capacity gain is limited by severe channelization code shortage under these circumstances. This problem is solved by deploying a cell splitting strategy with multiple code regions, which subsequently results in a capacity gain increase to a factor of 3.4. Furthermore, the soft capacity mechanism associated with partial deployment of AAs in a subset of the cells in the network is also addressed. It is demonstrated that a hot spot cell with AAs also helps increase the capacity of the surrounding cells with conventional sector antennas when using a power-based AC strategy.

A dynamic channel-borrowing approach with fuzzy logic control in distributed cellular networks

In this paper, a fuzzy-based dynamic channel-borrowing scheme (FDCBS) is presented to maximize the number of served calls in a distributed wireless cellular network. The uneven traffic load may create hot-spot cells and possibly causes a high blocking rate in hot-spot cells. Most conventional methods use load indices with a threshold value to determine the load status of a cell. However, those exists a ping–pong effect, as loads are around the threshold value. This result causes an unstable system and unnecessary message passing overhead. In addition, the estimation of traffic load is difficult and time-consuming. Thus, an intelligent prediction mechanism is needed. In this paper, we develop a method to predict the cell load and to solve the channel-borrowing problem based on the fuzzy logic control. A new channel-borrowing algorithm with multi-channels borrowing is also presented in this paper. A borrowing mechanism supporting the present facility has been built on the application-level of wireless cellular networks. The FDCBS exhibits better adaptability, robustness, and fault-tolerant capability thus yielding better performance compared with other algorithms. Through simulations, we evaluate the blocking rate, update overhead, and channel acquisition delay time of the proposed method. The results demonstrate that our algorithm has lower blocking rate, less updated overhead, and shorter channel acquisition delays.

An innovative channel management strategy for highly reliable handoff in cellular networks

AbstractIn this paper, we have resolved the problem of forced call termination that occurs when mobile traffic is concentrated on a hot‐spot cell in cellular networks. Enhanced Channel Management Scheme (ECMS) is an innovative way to increase the flexibility of channel usage over non‐uniform traffic distribution. ECMS exploits mobile hosts initiated or active in overlapping areas between cells. The scheme consists of three phases to monitor the status of channels on each base station and to make a channel reservation using the availability list maintained for the candidate‐MH selection. When the traffic load in a cell is intolerably high, ECMS invokes the load‐balancing procedure to distribute its traffic to adjacent cells. The reserved channels are used to support the safe and fast handoff. From the simulation, we observed that ECMS outperformed other compatible channel assignment schemes such as directed handoff schemes in blocking probability and channel utilization. Copyright © 2002 John Wiley & Sons, Ltd.

Adaptive admission control in wireless multimedia networks under non-uniform traffic conditions

Adaptive admission control in cellular wireless networks reserves bandwidth for handoff calls, which is proportional to the traffic intensity in the surrounding cells. This paper analyzes performance (QoS) of the adaptive admission algorithm in the presence of nonuniform traffic conditions in the network. We model the performance of small, moderate, and large hot-spots, and analyze average cell capacity utilizations and their derivatives when the hot-spot new call arrival rate is growing and surrounding cells operate at the constant load. The analysis shows that under sufficient bandwidth reservation, derivatives of the hot-spot cell capacity utilizations converge to zero for hot-spot call arrival rates larger than twice the nominal load. Since the average utilization is the linear combination of all the state probabilities of the Markov chain, the convergence of its derivative to zero under high offered loads means that the derivatives of other linear combinations of state probabilities, such as handoff dropping probability and new call blocking probability, will also converge to zero. Therefore, handoff dropping probability and new call blocking probability must be bounded by the logarithmic function of new call arrival rate for large arrival rates. Due to the feedback property embedded in the bandwidth reservation process, our admission algorithm offers QoS bounds both under nominal load and under high arrival rates. The analytical results have been validated by simulations.

Hot-spot traffic relief in cellular systems

By analyzing mathematical models, it is shown that combining channel borrowing with a coordinated sectoring or overlying scheme provides effective ways to handle hot-spots in the system. Blocking probabilities with these arrangements are derived, and the dynamic sharing with bias (DSB) rule is suggested for increasing the trunking efficiency. A simple handoff model is formulated and analyzed for comparing the probabilities of additional handoffs due to sectoring and overlaying of cells. With the nominal allocation of 60 channels per cell and a donor cell having a load of 30 Erlangs, numerical results show that at a blocking requirement of 1%, the traffic load in the hot-spot cell can be increased from 47 to 63 Erlangs with the use of the channel borrowing with the cell sectoring scheme: while with the use of the DSB rule, the load can be increased further to 71 Erlangs. A slightly higher load can be carried in the hot-spot cell with the use of cell overlaying arrangement. >