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When many cellular users take high capacity transit (HCT), a group of mobile terminals (MTs) may have to initiate handoffs and location updates more or less at the same time, which will cause congestion on the random access control channel (RACH), leading to many handoff and location update failures. To overcome this problem, we propose a new scheme, called GHA/RALU (Group Handoff Avoidance/Rate Adjusted...
Secondary wide-band users have to guarantee they will not disturb the in-band narrow-band primary licensed users. There are techniques proposed to limit the interference by secondary wide-band users in the specified in-band narrow bands. Active Interference Cancelation (AIC) can flexibly solve this problem in the digital domain and hence remove the need for extra expensive analog hardware. The main...
An advanced CSMA/CA (carrier sense multiple access with collision avoidance) system incorporating total precedence transmission of all CA and MAC frames (known as a full-flying synchronous CSMA/v-MCA system in Japan, where v- MCA means a variable multiple CA) was developed to minimize the time wasted for upstream channels. In this system, the CA procedures and the controls of the MAC frame transmission...
In this paper we address the problem of multicasting individual and common information from a single transmitter (source) to multiple receivers (destinations). We consider the general case where a separate message could be intended for any subset of destinations. We call this problem multicasting in broadcast channel. We derive an achievable rate region for this setup when the `deterministic channel...
In cognitive radio networks, it is important to effectively use the under-utilized spectrum resources without affecting the primary users. In an underlay system, cognitive users are allowed to share the channel simultaneously with primary users with the restriction on interference level but not in an overlay system. In this paper, we consider a system where cognitive users can switch between overlay...
Online social networks (OSNs) provide new means of disseminating information about applications and contents served by network providers. OSN members often reveal their usage information and opinion about applications and contents to their neighbors within their social networks. Consequently, sudden popularity and viral propagation of applications among OSN members can put significant burden on network...
In this paper we propose a low carbon emission IP over WDM network where renewable energy is used to reduce the CO2 emissions at a given energy consumption level. We develop a Linear Programming (LP) model to minimize the non-renewable energy consumption of the network and propose a novel heuristic for improving renewable energy utilization. Compared with routing in the electronic layer, the results...
Transport protocols that use explicit rate feedback are a promising alternative to the algorithms which use implicit, packet loss based feedback. A key issue in the design of rate controlled communication networks is how new flows may be admitted at a fair and high starting rate. In this paper, for the management of new flows we present a modified NetFPGA Rate Control Protocol (RCP) implementation...
Despite its existing incentives for leecher cooperation, BitTorrent file sharing fundamentally relies on the presence of seeder peers. Seeder peers essentially operate outside the BitTorrent incentives, with two caveats: slow downlinks lead to increased numbers of ``temporary" seeders (who left their console, but will terminate their seeder role when they return), and the copyright liability...
Traffic traces provide valuable data to researchers and organizations alike. However, organizations that provide this information do not wish to expose the internal workings of their networks to potential attack. Traffic trace anonymization attempts to mitigate this concern by hiding sensitive information while preserving most of the empirical value of the trace. Unfortunately, many attacks such as...
In traditional delay tolerant networks (DTNs), there exists a potential assumption that the nodes are willing to help others for packet forwarding. However, in the real application scenarios, such as civilian DTNs, selfish behaviors always widely exist. Therefore, the assumption that nodes are cooperative is not realistic in all applications. Currently, most of the existing incentive mechanism focuses...
This paper considers distributed protocol design for resource allocation (RA) problems. We propose a fully decentralized RA scheme based on the min-sum message passing (MP) approach in which each message is the solution of small distributed allocation problems. Due to the presence of cycles in the network graph, the MP routine may not converge to a fixed point. To this end, we introduce a reweighted...
Optimizing information flow in a dense wireless network using discrete methods can be computationally prohibitive. Instead of treating the nodes as discrete entities, these networks can be modeled as continuum of nodes providing a medium for information transport. To model information routes in continuous space, information flow vector field is defined over the geographical domain of the network....
The relay-assisted Orthogonal Frequency-Division Multiple Access (OFDMA) cellular system is one of the most promising technology thanks to the enhancements of the system capacity and coverage it provides. However, some special features may lower its positive aspects. In multiple relay case, the asymmetric link problem in the two stages forming the relaying process may result in important resource...
To mitigate various physical impairments of long-haul dense wavelength division multiplexing (DWDM) systems and exploit their system capacity, there is a need to develop a two-dimensional (time and wavelength) discrete-time input-output model which can become the foundation of signal processing for optical communications. As the first step, this paper develops a model for single channel multipulse...
Regular LDPC codes tend to have better error-floor behavior than irregular LDPC codes. However, for moderate block lengths and high rates, the error floor remains a concern even for regular LDPC codes. This is especially the case for applications such as memory media that require very low frame error rates (FERs). This paper focuses on a class of regular LDPC codes: separable, circulant-based (SCB)...
With the advent of cloud computing, organizations tend to buy services from data centers of major cloud vendors. In contrast, community cloud computing as described in [1] give the alternative way to reduce the costs or even obtain free resources, by sharing among communities. Because the utilization of computing resources in an organization is not constantly 100%, other members of the community can...
In this paper, we propose an effective way of improving the performance of channel estimation for MIMO single-carrier block transmission (SCBT) systems. The proposed method utilizes the property that the shift of the cyclic pilot signal of each antenna branch can also be utilized to catch the channel information as a new pilot. The receiver can continuously estimate the channel information by just...
We present a new loss model for the call-level analysis of a single link, which accommodates calls of different service-classes with elastic bandwidth requirements. Calls arrive in the link according to a Batch Poisson process, a process that can be used to model traffic, which is more 'peaked' and 'bursty' than the Poisson process. The available link bandwidth is shared to calls according to the...
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