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The opportunistic network has become an appealing paradigm since it can reduce the energy consumption and cost on cellular network connections and relieve the communication burden of cellular networks. The probabilistic transmission scheme has been proposed as one of the typical opportunistic transmission schemes. However, most existing probabilistic transmission schemes neglect that, opportunistic transmission tasks in some applications have transmission time and cost budgets, and to set proper delay and hop count thresholds on encountering probabilities between relay nodes and their destination nodes can help to filter redundant long‐delay and high‐cost opportunistic paths for packets. In this study, the authors proposed a delay‐aware and cost‐efficient probabilistic transmission method for opportunistic networks. In this method, direct and indirect encountering probabilities related to delay and hop count are defined, and accordingly, a relay node selection algorithm is provided with preset encountering delay and hop count thresholds to compare probabilities of nodes to encounter the destination node within the preset thresholds as their transmission quality metrics. The simulation results verify that the proposed method can reduce transmission delay and cost efficiently.

Relay-assisted device-to-device (D2D) communications have been proposed as a supplement for direct D2D communications to enhance traffic offloading capacity. In this study, the authors propose a joint mode selection, relay selection and resource allocation for relay-assisted D2D communications. They aim at maximising the overall system throughput while guaranteeing the power limitation and signal-to-noise-and-interference ratios of all cellular and active D2D links. Since this optimisation is NP-hard, they then propose a graph colour-based resource allocation algorithm to effectively solve it. Simulation results show that the proposed algorithm can produce close-to-optimal performance with acceptable computational complexity.

Recently, the mobile traffic demand is increasing due to the drastic growth in the number of connected devices and smart services utilizing wireless cellular networks. In order to deal with this tough challenge, a key technology in 5G cellular networks, Multi-Access Edge Computing (MEC) which can provide ultra-low end-to-end latency, significant reduction of traffic load on backhaul, etc., has come into sight. The potential benefits of MEC in 5G and beyond have been revealed by plenty of state-of-the-art works. However, it leaves a difficult problem for the operators, which is to determine whether and how to deploy MEC in cellular networks due to the uncertainty of feedback from the investment on MEC. Although, there were a few works studying on the optimization of the number of MEC from the viewpoint of telecom operators, their contribution focus only on telecom operators rather than taking other operators (backhaul owners, Cloud owners, etc.) into account. In this paper, we propose a social maximization revenue model with the investment strategy for the telecom operators who decide the number of MEC and the backhaul owner who lease the backhaul capacity. The numerical results indicate that the optimal number of MEC and backhaul capacity that maximize the two players' profit is the same. Hence, it turns out that the advantage of MEC can be highlighted by using both Cloud and edge resource in parallel rather than processing all traffic on the MEC side.

Proceeding of: 2020 IEEE International Symposium on Information Theory (ISIT), Los Angeles, CA, USA, 21-26 June 2020 The channel capacity of wireless networks Is often studied under the assumption that the communicating nodes have perfect channel-state information and that interference is always present. In this paper, we study the channel capacity of a wireless network without these assumptions, i.e., a bursty noncoherent wireless network where the users are grouped in cells and the base-station features several receive antennas. We demonstrate that the channel capacity is bounded in the signal-to-noise ratio (SNR) when the number of receive antennas is finite and the probability of presence of interference is strictly positive. This work has been supported in part by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant No. 714161), and by the Spanish Ministerio de Economía y Competitividad under Grants RYC-2014-16332 and TEC2016-78434-C3-3-R (AEI/FEDER, EU).

Inspired by a new feature in 5G NR called bandwidth part (BWP), this paper presents a bandwidth allocation (BA) model that allows one to adapt the bandwidth allocated to users depending on their data rate needs. Specifically, in adaptive BA, a wide bandwidth is divided into chunks of smaller bandwidths and the number of bandwidth chunks allocated to a user depends on its needs or type. Although BWP in 5G NR mandates allocation of a set of contiguous bandwidth chunks, our BA model also allows other assumptions on chunk allocation such as the allocation of any set of bandwidth chunks, as in, e.g., LTE resource allocation, where chunks are selected uniformly at random. The BA model studied here is probabilistic in that the user locations are assumed to form a realization of a Poisson point process and each user decides independently to be of a certain type with some probability. This model allows one to quantify spectrum sharing and service differentiation in this context, namely to predict what performance a user gets depending on its type as well as the overall performance. This is based on exact representations of key performance metrics for each user type, namely its success probability, the meta distribution of its signal-to-interference ratio, and its Shannon throughput. We show that, surprisingly, the higher traffic variability stemming from adaptive BA is beneficial: when comparing two networks using adaptive BA and having the same mean signal and the same mean interference powers, the network with higher traffic variability performs better for all these performance metrics. With respect to Shannon throughput, we observe that our BA model is roughly egalitarian per Hertz and leads to a linear service differentiation in aggregated throughput value., Comment: IEEE INFOCOM 2020

According to the standard for the GSM for railway (GSM-R) wireless systems in China train control system level 3 (CTCS-3), the control data transfer delay should be no larger than 500ms with greater than 99% probability. Coverage of both non-redundant networks and intercross redundant networks and cases of single Mobile terminals (MTs) and redundant MTs on one train are considered, and the corresponding vehicle-ground communication models, delay models, and fault models are constructed. The simulation results confirm that the transfer delay can meet the standard requirements under all cases. In particular, the probability is greater than 99.996% for redundant MTs and networks, and the standard of transfer delay in CTCS-3 will be improved inevitably.

this paper discusses approaches to implement the Recursive Internet Architecture in a 5G cellular radio access network. It lists the motivations to do so, five approaches, and requirements for networks and client terminals in each case. The approaches are compared based on relative effort to implement and how they align with the motivations, and concludes with considerations for prototyping of RINA over 5G.

© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. Stringent demands for a continuous evolution of cellular networks push today academic and industrial researchers to re-think backhaul solutions for 5G. In one hand, wireless backhaul solutions are cost effective and easy to deploy but suffer from limited capacity. On the other hand, wired solutions have the potential to meet bandwidth requirements but usually involve higher costs. Thus, adoption of heterogeneous technologies will be necessary. Moreover, in 5G, access and backhaul networks will work closely, and therefore, total separation of their resources may not be possible anymore; rather, cooperation between the two portions of the cellular network is desirable. Subsequently, cooperative access-backhaul mechanisms become necessary to ensure the best use of the scarce resources, i.e. bandwidth. Hence, in this paper we present the idea of spectrum sharing among different links from a cooperative access-backhaul mechanism point of view. We present simulation results for different approaches of such sharing from a common spectrum pool. The results show that traffic-aware approaches show increased fairness thus reinforcing the idea of cooperative access-backhaul mechanisms as essential strategies in current and future networks.

Evolved Multimedia Broadcast Multicast Service (eMBMS) is a 3GPP standard that improves the utilization of scarce wireless resources and the quality of the received content. eMBMS uses a Single Frequency Network (SFN) to transmit real-time videos over synchronized resources across neighboring base stations (eNBs) and allows users to share wireless spectrum across multiple cell sites. However the user with the worst channel condition and the eNB with the least available resources limit the throughput of a session. To overcome such limitations, the SFN can be divided into non-overlapping clusters of eNBs and in each cluster users can be split into groups. We formulate an optimization problem that maximizes an operator-defined utility for multiple eMBMS sessions served at multiple bitrates by choosing the optimal set of SFN clusters and user groups for each session. We propose an algorithm, RTOP, that finds the optimal or a near-optimal solution in real-time regardless of the number of eMBMS users. Our extensive simulations indicate that, in comparison to state-of-the-art schemes, RTOP improves the system utility and average user bitrate by up to 14% and 90% respectively. Additionally, we show that the utility of RTOP always stays within a 1% gap from the optimal solution.

The VST-TDMA access protocol has shown to have many advantages over existing protocols in centralized (star) wireless network architectures. As most data-link layer protocols, it does not have a recovery feature as data integrity is supervised by the connection-oriented transport protocols. Nevertheless, VST-TDMA possesses the flexibility to easily incorporate a retransmission feature that allows the users to experience higher throughput when using applications that use the Transmission Control Protocol, which transports approximately 90% of all Internet traffic. Results show that depending on the wireless link reliability, i.e., the frame loss rate, the throughput can be improved by a factor of ten. The VST-TDMA access protocol has shown to have many advantages over existing protocols in centralized (star) wireless network architectures. As most data-link layer protocols, it does not have a recovery feature as data integrity is supervised by the connection-oriented transport protocols. Nevertheless, VST-TDMA possesses the flexibility to easily incorporate a retransmission feature that allows the users to experience higher throughput when using applications that use the Transmission Control Protocol, which transports approximately 90% of all Internet traffic. Results show that depending on the wireless link reliability, i.e., the frame loss rate, the throughput can be improved by a factor of ten.

In cellular-based public safety networks, user equipments (UEs) located in coverage area of active cells are able to act as relay UEs (RUEs). These RUEs provide cellular services to isolated UEs (IUEs). Due to mobility of both an IUE and a RUE, a link between them may be disconnected. Thus, it is necessary to newly establish a link between the IUE and another RUE. Unfortunately, it may cause that packets sent by previous RUE to be lost during the link re-establishment procedure. An efficient sidelink re-establishment procedure is proposed to reduce link re-establishment set-up delay. The performance of the proposed method compared with the conventional scheme used in 3rd Generation Partnership Project is evaluated. The proposed scheme shows better performance than the conventional scheme in terms of signalling overhead and set-up delay for sidelink re-establishment.

The main resource for any telecom operator is the physical radio cell network. We present two related methods for optimizing utilization in radio networks: Tetris optimization and selective cell expansion. Tetris optimization tries to find the mix of users from different market segments that provides the most even load in the network. Selective cell expansion identifies hotspot cells, expands the capacity of these radio cells, and calculates how many subscribers the radio network can handle after the expansions. Both methods are based on linear programming and use mobility data, i.e., data defining where different categories of subscribers tend to be during different times of the week. Based on real-world mobility data from a region in Sweden, we show that Tetris optimization based on six user segments made it possible to increase the number of subscribers by 58% without upgrading the physical infrastructure. The same data show that by selectively expanding less than 6% of the cells we are able to increase the number of subscribers by more than a factor of three without overloading the network. We also investigate the best way to combine Tetris optimization and selective cell expansion. © 2018 The Author(s) open access

Proceedings of: 16th International Symposium on Wireless Communication Systems (ISWCS), 27-30 August 2019, Oulu, Finland. Visible light communication (VLC) is a promising communication technology that paves the way to the Internet of Things. The forthcoming Industry 4.0 requires reliable high-speed communication links, which can be easily fulfilled with the massive adoption of the VLC technology. However, in VLC indoor communication environments, line-of-sight link blockages and strong misalignment losses between the light-emitting diode (LED) transmitters and the photodiode (PD) receivers are usual problems that must be tackled. This paper proposes a coordinated multi-point (CoMP) transmission technique to deal with both issues, and carries out a detailed evaluation of the VLC system performance as function of the PD receiver orientation and the density of obstacles in different scenarios. The proposed cooperative transmission scheme demonstrates an improvement in the average cell data rate and outage probability performance and, as a consequence, justifies the use of CoMP techniques to provide reliable VLC services in ultra-dense small cell scenarios indoors. This work has been partially funded by the Spanish MECD FPU fellowship program granted to the author B. Genoves Guzmán, the Catalan Government under Grant 2017SGR1479, and the Spanish Government under the national project 'TERESA-ADA' with ID no. TEC2017-90093-C3-2-R/1-R (MINECO/AEI/FEDER, UE).

The fifth generation (5G) of cellular systems is introducing Ultra-Reliable Low-Latency Communications (URLLC) services alongside more conventional enhanced Mobile BroadBand (eMBB) traffic. Furthermore, the 5G cellular architecture is evolving from a base station-centric deployment to a fog-like set-up that accommodates a flexible functional split between cloud and edge. In this paper, a novel solution is proposed that enables the non-orthogonal coexistence of URLLC and eMBB services by processing URLLC traffic at the Edge Nodes (ENs), while eMBB communications are handled centrally at a cloud processor as in a Cloud-Radio Access Network (C-RAN) system. This solution guarantees the low-latency requirements of the URLLC service by means of edge processing, e.g., for vehicle-to-cellular use cases, as well as the high spectral efficiency for eMBB traffic via centralized baseband processing. Both uplink and downlink are analyzed by accounting for the heterogeneous performance requirements of eMBB and URLLC traffic and by considering practical aspects such as fading, lack of channel state information for URLLC transmitters, rate adaptation for eMBB transmitters, finite fronthaul capacity, and different coexistence strategies, such as puncturing., Submitted as Journal Paper

The possibilities for positioning in cellular networks has increased over time, pushed by increased needs for location based products and services for a variety of purposes. It all started with rou ...

In this paper, a cognitive-radio-inspired asymmetric network coding (CR-AsNC) scheme is proposed for multiple-input–multiple-output (MIMO) cellular transmissions, where information exchange among users and base-station (BS) broadcasting can be accomplished simultaneously. The key idea is to apply the concept of cognitive radio (CR) in network coding transmissions, where the BS tries sending new information while helping users' transmissions as a relay. In particular, we design an asymmetric network coding method for information exchange between the BS and the users, although many existing works consider the design of network coding in symmetric scenarios. To approach the optimal performance, an iterative precoding design for CR-AsNC is first developed. Then, a channel-diagonalization-based precoding design with low complexity is proposed, to which power allocation can be optimized with a closed-form solution. The simulation results show that the proposed CR-AsNC scheme with precoding optimization can significantly improve system transmission performance.

With growing data demand and the current dearth of spectrum, mobile operators are looking for new frequency bands to satisfy data-hungry users. One promising avenue of expansion is TV white spaces, which are currently available to secondary users as long as they do not interfere with primary (i.e., incumbent) users. In this work, we explore the benefits of offloading cellular traffic onto TV white spaces. We develop an analytical model and efficient algorithms to assign users to the cellular network or white space channels by considering their channel gains, multi-user interference on white space channels, and the cost of switching between different networks. We perform extensive data-driven simulations in two representative urban scenarios based on publicly available datasets. Our results show that white spaces can increase capacity by 16–62%, depending on the environment, but careful network selection is necessary to ensure that maximum capacity gains are realized. Moreover, we show that white spaces provide a significant benefit in serving indoor users where cellular channel conditions are poor. Specifically, our algorithms can offload up to 40% of cellular traffic to white spaces for indoor scenarios.

In this paper, we study merging Device-to-Device (D2D) communication with full-duplex (FD) communications under different resource allocation strategies, i.e., reuse, dedicated and cellular. In reuse strategy, the D2D communication takes place directly between D2D pair sharing the whole resources together with the cellular user, while in dedicated strategy, the direct D2D communication is given half of the resources. Enabling cellular strategy, however, the data of D2D communication goes through the Base Station (BS). In this study, we take into account both FD and half-duplex (HD) modes incorporating into reuse, dedicated and cellular strategies, and formulate the resource allocation problem in a two-tier system. Aiming to maximize the system throughput, we analyze the system adopting different duplex-modes and resource allocation strategies. Simulation results demonstrate that the superiority of FD communication is contingent to self-interference (SI) cancelation factor. Through deriving geographical patterns, we analyze the effect of location of cellular user on mode selection strategy taken by D2D pair to pick the best strategy. The results show that the dedicated strategy is the best choice when the cellular user is close to the D2D pair, while the reuse strategy is dominant, when opposite state holds. Furthermore, the results reveal that the system achieves the maximum throughput under reuse strategy when the cellular user is located close to BS.

Considering coordinated multipoint joint transmission in a user-centric fashion in an ultra-dense network, performance analysis is conducted from a network perspective with respect to the user's performance gain and the access point's (AP's) backhaul burden. First, the ergodic capacity (EC) of a typical user is characterised. Secondly, per-AP backhaul consumption is explicitly quantified and the successful serving probability of a typical AP is proposed to capture its robustness to limited backhaul capacity. Finally, effective EC to weigh performance gain and backhaul consumption simultaneously is propounded. Simulation results show the effectiveness of the proposed metrics and reinforce that a comparatively small size is preferable in practice.

A machine-to-machine (M2M) communications system is a large-scale network with diverse applications and a massive number of interconnected heterogeneous machines (e.g., sensors, vending machines and vehicles). Cellular wireless technologies will be a potential candidate for providing the last mile M2M connectivity. Thus, the Third Generation Partnership Project (3GPP) and IEEE 802.16p, have both specified an overall cellular M2M reference architecture. The European Telecommunications Standards Institute (ETSI), in contrast, has defined a service- oriented M2M architecture. This article reviews and compares the three architectures. As a result, the 3GPP and 802.16p M2M architectures, which are functionally equivalent, complement the ETSI one. Therefore, we propose to combine the ETSI and 3GPP architectures, yielding a cellular-centric M2M service architecture. Our proposed architecture advocates the use of M2M relay nodes as a data concentrator. The M2M relay implements a tunnel-based aggregation scheme which coalesces data from several machines destined to the same tunnel exit-point. The aggregation scheme is also employed at the M2M gateway and the cellular base station. Numerical results show a significant reduction in protocol overheads as compared to not using aggregation at the expense of packet delay. However, the delay rapidly decreases with increasing machine density. Refereed/Peer-reviewed

Currently cellular networks do not have sufficient capacity to accommodate the exponential growth of mobile data requirements. Data can be delivered between mobile terminals through peer-to-peer WiFi communications (e.g. WiFi direct), but contacts between mobile terminals are frequently disrupted because of the user mobility. In this paper, we propose a Sub-scribe-and-Send architecture and an opportunistic forwarding protocol for it called HPRO. Under Subscribe-and-Send, a user subscribes contents on the Content Service Provider (CSP) but does not download the subscribed contents. Some users who have these contents deliver them to the subscribers through WiFi opportunistic peer-to-peer communications. Numerical simulations provide a robust evaluation of the forwarding performance and the traffic offloading performance of Subscribe-and-Send and HPRO.

We study low-signalling overhead scheduling for downlink coordinated multi-point (CoMP) transmission with multi-antenna base stations (BSs) and single-antenna users. By exploiting the asymmetric channel feature, i.e., the path-loss differences towards different BSs, we derive a metric to judge orthogonality among users only using their average channel gains, based on which we propose a semi-orthogonal scheduler that can be applied in a two-stage transmission strategy. Simulation results demonstrate that the proposed scheduler performs close to the semi-orthogonal scheduler with full channel information, especially when each BS is with more antennas and the cell-edge region is large. Compared with other overhead reduction strategies, the proposed scheduler requires much less training overhead to achieve the same cell-average data rate.

The objective of this chapter is to study practical coding techniques to provide security to wireless systems. First, the chapter will briefly introduce theoretical results relevant to low density parity check (LDPC) codes, polar codes and lattice coding for the wiretap channel. Then, it will propose practical secrecy-coding schemes able to provide a reliable and confidential wireless communication link betweenAlice and Bob. Finally, these practical wiretap codes are implemented in WiFi and long-term evolution (LTE) testbeds, and their confidentiality performance is evaluated using the bit-error rate (BER) as it is a simple and practical the metric for secrecy. The reader is referred to [1] for a throughout survey on recent advances related to the design of wiretap codes for information-theoretic metrics such as strong secrecy and semantic secrecy.

Access to reliable high-quality communication services on trains is important for today's mobile users. Train-mounted aggregation routers that provide WiFi access to train passengers and bundle external communication over multiple cellular modems/links is an efficient way of providing such services. Still, the characteristics of such systems have received limited attention in the literature. In this paper we examine the communication characteristics of such systems based on a large data set gathered over six months from an operational Swedish railway system. We characterize the conditions in terms of usage load, train velocity profiles, and observed throughput and delay as well as the relation between these parameters. Furthermore, we examine the data from an anomaly detection perspective. Based on a changepoint detection method, we examine how the collected metrics varies over the six months. Being able to detect shifts in the metrics over time can help detect anomalous changes in the hardware or environment, and also further helps explain the factors affecting the observed behaviors. HITS

International audience; The main objective of this chapter is to study explicit key extraction techniques and algorithms for the security of radio communication. After some recalls on the main processing steps (Figure 19.1(a)) and on theoretical results relevant to the radio wiretap model (Figure 19.1(b)), we detail recent experimental results on randomness properties of real field radio channels. Furthermore, we detail a practical implantation of secret key generation (SKG) schemes, based on the Channel Quantization Alternate (CQA) algorithm helped with channel decorrelation techniques, into modern public networks such as WiFi and radio-cells of fourth generation (LTE, long-term evolution). Finally, through realistic simulations and real field experiments of radio links, we analyze the security performance of the implemented SKG schemes, and highlight their significant practical results and perspectives for future implantationsinto existing and next-generation radio standards.

Multicell cooperation may play an important role in achieving high performance in cellular systems. Multicell cooperation with a single receive antenna at the mobile station has been widely investigated. Applying cooperation with multiple receive antennas, allowed in several emerging wireless standards, has met with some challenges. This is primarily because the transmit precoding/beamforming vector and receive processing have to be jointly optimized in multiple cells to combat out-of-cell interference. In this article, we first discuss the role of the receive antennas in a multicell environment, and then review recently proposed multicell cooperative algorithms and receive antenna techniques for different interference statistics. Finally, we highlight recent work on the fundamental limits of cooperation and the possibility of overcoming such limits by using multiple receive antennas in multicell cooperative networks.

There are two basic principles used in wireless network coding to design throughput-efficient schemes: (1) aggregation of communication flows and (2) interference is embraced and subsequently cancelled or mitigated. These principles inspire design of many novel multi-flow transmission (MFT) schemes. Such are the Coordinated Direct/Relay (CDR) schemes, where each basic transmission involves two flows to a direct and a relayed user. Usage of MFT schemes as building blocks of more complex transmission schemes essentially changes the problem of scheduling, since some of the flows to be scheduled are coupled in a signal domain and they need to be assigned a communication resource simultaneously. In this paper we define a novel framework that can be used to analyze MFT schemes and assess the system-level gains. The framework is based on cellular wireless users with two-way traffic and it sets the basis for devising composite time-multiplexed MFT schemes, tailored to particular optimization criteria. Those criteria can be formulated by adapting well-known schedulers in order to incorporate MFT schemes. The results show rate advantages brought by the CDR schemes in pertinent scenarios. Another key contribution is the proposed framework, which can be used to evaluate any future multi-flow transmission scheme.

In the literature, numerous works have modeled user activity on smartphones and the effects on battery life. Power-saving modes prolong battery life by saving energy, but application performance is limited as a result. We investigate performance-energy trade-offs of smartphone applications by investigating three strategies: first, we propose an M/M/1 discriminatory processor sharing queue to act as a smartphone server and measure delays of Android applications; secondly, we form a performance-energy trade-off that takes into account cellular radio transfers using an objective cost function incorporating mean delay and power consumption; and thirdly, we build an online HMM to act as a power consumption model that predicts battery life given recent data transfers. For all three strategies, we obtain logged smartphone activity of over 750 users via an open-source smartphone data-collection application. Hence, we obtain three hypotheses from our strategies: first, delay of applications is approximated well using the beta prime distribution; secondly, power consumption increases as mean delay decreases with battery life prolonged if adjustments are made to cellular radio usage; and thirdly, burstiness is captured by HMMs in both data transfers and rates of power consumption.

Dynamic adaptive video over HTTP (DASH) is fast becoming the protocol of choice for content providers for their online video streaming delivery. Concurrently, dependence on cellular Long Term Evolution (LTE) networks is growing to serve user demands for bandwidth-hungry applications, especially video. Each LTE base station's (eNodeB) scheduler assigns wireless resources to individual clients. Several alternative schedulers have been proposed, especially to meet the user's desired quality of experience (QoE) with video. In this paper, we investigate the impact of the scheduler on DASH performance, motivated by the fact that video performance and the underlying traffic models are different from other HTTP/TCP applications. We use our laboratory testbed employing real video content and streaming clients, over a simulated ns-3 LTE network. We quantify the impact of the scheduler and show that it has a significant impact on key video streaming performance metrics such as stalls and QoE, for different client adaptation algorithms. Additionally, we show the impact of user mobility within a cell, which has the side-effect of improving performance by mitigating long-term fading effects. Our detailed assessment of four LTE schedulers in ns-3 shows that the proportional fair scheduler achieves the best overall user experience, although somewhat disadvantaging static cell-edge users.

Remote coalition network elements (CNEs) are proposed for base station (BS) cooperation, where the CNEs carry traffic in the second hop for the primary BS in support of its cell-edge mobile stations (MSs) by exploiting the unused frequency bands of the main BS network while considering a range of practical impairments. We derive the coalition probability of the CNEs by taking into account both the specific system load and the CNE's greediness factor. Our simulation results demonstrate that the proposed solution is capable of substantially increasing the attainable signal-to-interference-plus-noise ratio (SINR) in a wide range of scenarios, and it is also robust to diverse practical imperfections. We demonstrate that the maximal sum profit of the main BS network and the CNE network is achieved at a greedy factor of 0.45 when the MSs are located in the range of r

Most of us would like to get rid of as many cords and cables as possible. Some have said that a goal for this decade is to replace them with wireless connections. In this article, the author discuss one of the ways of making a wireless communication link - the cellular modem. This paper describe an off-the-shelf solution to connectivity over the cellular network: the cellular engine terminal.

Base Station Cooperation Transmission of OFDM symbols (BSC-OFDM) is a promising approach to increase cell-edge capacity. The effect of Ranging Error on BSC-OFDM is investigated in this paper. Timing offset greater than 1 OFDM symbol in analytically duration creates asynchronous interference. Results show that a single ranging code transmitted by a mobile station provides greater capacity over a scheme with a separate orthogonal ranging code for each base station.

The unique wide-scale geographical coverage offered by satellite networks, coupled with its inherent broadcast/multicast capabilities and highly reliable connectivity, anticipates new opportunities for the integration of the satellite component into the 5G ecosystem. One of the most compelling scenarios is mobile backhauling, where satellite capacity can be used to complement the terrestrial backhauling infrastructure, not only in hard to reach areas, but also for more efficient traffic delivery to radio access network (RAN) nodes, increased resiliency and better support for fast, temporary cell deployments and moving cells. In this context, this paper proposes a model for the analysis of capacity and traffic management strategies in hybrid satellite-terrestrial mobile backhauling networks that rely on Software Defined Networking (SDN) for fine-grained traffic steering. Numerical results are provided to assess the capacity gains that can be achieved when the satellite backhaul capacity is used for traffic overflow, taking into account the placement of the satellite capacity at different traffic aggregation levels and the spatial correlation of the traffic demand.

Direct device-to-device (D2D) links are proposed as a possible enabler for vehicle-to-vehicle (V2V) communications, where the incurred intracell interference and the stringent latency and reliability requirements are challenging issues. In this paper, we investigate the radio resource management problem for D2D-based V2V communication. First, we analyze and transform the latency and reliability requirements of V2V communication into optimization constraints that are computable using only the slowly varying channel information. This transformation opens up the possibility of extending certain existing D2D techniques to cater to V2V communication. Second, we propose a problem formulation that fulfills the different requirements of V2V communication and traditional cellular communication. Moreover, a Separate resOurce bLock and powEr allocatioN (SOLEN) algorithm is proposed to solve this problem. Finally, simulations are presented to evaluate different schemes, which illustrate the necessity of careful design when extending D2D methods to V2V communication, as well as show promising performance of the proposed SOLEN algorithm.

The spectrum pooling strategy allows a license owner to share a part of his licensed spectrum with a secondary wireless system (the rental system, RS) during its idle times. The coexistence of two mobile systems on the same frequency band poses many new challenges, one of which is the reliable extraction of the channel allocation information (CAI), i.e. the channel occupation of the licensed system (LS). This paper presents a strategy for the extraction of the CAI based on exploiting the distinct cyclostationary characteristics of the LS and RS signals and demonstrates, via simulations, its application on a specific spectrum pooling scenario, where the LS is a GSM network and the RS is an OFDM based WLAN system. Publisher's Version Q1 WOS:000245226000006

In the vision of the upcoming 5G communications expected to allow Internet access to different heterogeneous devices, the problem of Indoor access is under the lens of the scientific community. In order to guarantee electromagnetic safe and secure access, Visible Light Communications can be considered an enabler. In this regard trying to optimize very small cells (atto-cells) coverage is a challenging task especially if some metrics, as for example average user rate, is considered also in the presence of handover procedures. This problem is equivalent to the optimal LEDs placement once assigned the dimension of the room to be covered. We give evidence of the impact of several parameters starting from the data rate of download, the speed of the user in the room as well the handover time and retransmission due to detection errors.

The widespread diffusion of powerful mobile devices with diverse networking and multimedia capabilities, and the associated blossoming of content-centric multimedia services is contributing to the exponential increase of data traffic in cellular networks. Mobile data offloading is a promising technique to cope with these problems, which allows to deliver data originally targeted for cellular networks to complementary networking technologies. Among the various forms of mobile data offloading in this study we focus on offloading through opportunistic networks. Differently from previous studies in this field we evaluate the efficiency of opportunistic offloading schemes by using a real cellular traffic dataset collected in a large metropolitan area over a period of one month. We focus our analysis on video requests for popular video providers, and we evaluate the potential benefits of using an opportunistic data dissemination scheme to request this videos from local users instead of using the cellular network. As a benchmark, we compare the performance of such system with a simple caching mechanism. We show that a simple opportunistic offloading scheme can improve the performance of the caching system even if only 10% of the users participate in the opportunistic dissemination. This means that operators could offload their network efficiently without needing to deploy additional caching infrastructure.

LTE is rapidly gaining momentum for building future 4G cellular systems, and real operational networks are under deployment worldwide. To achieve high throughput performance, in addition to an advanced physical layer design LTE exploits a combination of sophisticated mechanisms at the radio resource management layer. Clearly, this makes difficult to develop analytical tools to accurately assess and optimise the user perceived throughput under realistic channel assumptions. Thus, most existing studies focus only on link-layer throughput or consider individual mechanisms in isolation. The main contribution of this paper is a unified modelling framework of the MAC-level downlink throughput of a sigle LTE cell, which caters for wideband CQI feedback schemes, AMC and HARQ protocols as defined in the LTE standard. We have validated the accuracy of the proposed model through detailed LTE simulations carried out with the ns-3 simulator extended with the LENA module for LTE.

HTTP streaming currently dominates Internet traffic. It is increasingly common that video players employ adaptive bitrate (ABR) streaming strategies to maximise the user experience by selecting the highest video representation while targeting stall-free playback. Our interest lies in the common situation where a set of video flows are competing for access to a shared bottleneck link, such as in a cellular radio access network. We observe that ISPs (e.g. cellular operators) are considering innetwork techniques for resource allocation and sharing among different users. Buoyed by the ability of software defined networks (SDN) to offer flow-specific control and traffic shaping, we focus on traffic shaping techniques, and experimentally analyse the effect on ABR video flows when sharing a bottleneck link. We conduct experiments using the GPAC video player operating over a Mininet virtual network. We conclude that traffic shaping can allow a balance of fairness, efficiency and quality. Traffic shaping ABR videos reduce the number of stalls and quality switches, while also reducing the peaks for the aggregate network traffic.

This article provides a comparative study of different multiple access techniques. It is demonstrated that non-orthogonal approaches have a spectral-power efficiency advantage over orthogonal ones for delay-sensitive applications in fading environments, and that this theoretical advantage can be realized in practice by exploiting recent progress in transmission and detection techniques. The practical aspects of these multiple access techniques are also discussed and compared

Weevaluatethecapacitiesofcodedivisionmultipleaccess(CDMA)andtimedivisionmultipleaccess(TDMA)schemesinanaeronauticalenvironment.Themodelfortheenvironment is a three-dimensional cellular arrangement, analogous to the two-dimensional model used for terrestrial cellular radio. The transmission schemes we consider are based upon those of terrestrial cellular, suitably modified to accommodate the unique requirements of pilot-tocontroller communications in civilian air-to-ground communication settings. In accounting forthenearfree-spacepropagationofinterference,weemploynewparametervaluesrequired for the estimation of capacities in the aeronautical environment: theTDMA frequency re-use factorandtheCDMAoutsidecellinterferencefactor.Baseduponthemodifiedterrestrialcellular schemes and these new parameters, we show that if average interference is considered, CDMA capacity is largest. If worst-case interference is considered, the half-duplex TDMA capacity is comparable to the CDMA capacity when the CDMA system uses rebroadcast of air-ground transmissions in the ground-air link, but if this rebroadcast mode is not used, worst-case CDMA capacity is also larger than worst-case TDMA capacity.

Link Adaptation is an adaptive radio resource management technique that selects a transport mode from a set of predefined modes of varying robustness, depending on the experienced channel quality conditions and dynamics. Previous work has shown the need to adapt the configuration of Link Adaptation to certain operating conditions affecting the channel quality dynamics. In particular, it was shown that the system load can considerably influence the performance and configuration of Link Adaptation techniques. The user mobile speed is another key factor influencing the channel quality dynamics. As a result, the aim of this paper is to investigate whether the user mobile speed should also be taken into account when configuring and designing the operation of Link Adaptation techniques.

Deregistration due to the departures of mobile users from their current visiting registration area may cause significant traffic in the wireless cellular networks. In this paper, we propose a hierarchical implicit deregistration scheme with forced registration in third-generation wireless cellular networks to reduce the remote/international roaming signaling traffic when home-location registers (HLRs), gateway-location registers (GLRs), and the visitor-location registers (VLRs) form a three-level database hierarchy. In this scheme, if a mobile phone arrives and the GLR/VLR is full, a random record is deleted and the reclaimed storage is reassigned to the new arriving mobile phone. When a call arrives and the callee's record is missing in the GLR/VLR, forced registration is executed to restore the GLR/VLR record before the call-setup operation proceeds. An analytic model is proposed to carry out the performance evaluation for the proposed scheme. Our results show that the proposed scheme not only reduces the local deregistration traffic between the GLR and the VLR, but also reduces the remote/international deregistration traffic between the HLR and the GLR, especially when the ratio of the cost of the remote/international traffic between GLR and HLR to the cost of local traffic between the VLR and the GLR is high.

Higher-speed wireless services are in the offing: both faster IEEE 802.11 standards and the much-maligned third-generation (3G) cellular systems, which, despite uninspiring debuts in cellphone-friendly Japan, are poised for a much better reception in coming months there and in places like China and the USA. And coming not much later will be true broadband wireless networks - pure Internet-protocol (IP) voice-capable 2-Mbit/s-and-higher data networks for which some analysts are even using the term 4G.

Cellular radio interfaces on smartphones consume a significant amount of battery power, specially with growing number of network centric applications. With high bandwidth cellular access links pushing the bottleneck to the network core, the risk of poor bandwidth utilization of the access link increases, which leads to energy wastage as the radio interface must stay active longer. In addition, small sized packet transmissions from applications wake up the interface frequently, but do not require the entire bandwidth capacity. In this work, we improve the radio usage by aggregating packet transmission from multiple applications. We introduce different time delays while transmitting packets from foreground and background applications such that user experience is minimally impacted. Through empirical observations, we determine the impact of different types of traffic on bandwidth utilization. Naive attempts to improve bandwidth utilization lead to increase in the number of packets missing the deadline for dispatch. With these observations, we propose a technique that balances the bandwidth utilization and deadline misses. Simulation driven experiments using synthetic traces and real trace based on application usage on Android based smartphones show energy gain of around 10% over other competing techniques.

The flexibility and convenience offered by mobile communication have made it one of the fastest growing areas of telecommunications, and communication security has become particularly significant and prominent. One of the most challenging security threats is the attack of rogue base station which posing as a radio transceiver station. It uses the same high-power electromagnetic frequencies to occupy the spectrum resources to send large amounts of spam messages. Rogue base station, if undetected, can be an open door to sensitive in-formation. In this paper, we present the process which rogue base station exploits security vulnerabilities to at-tack. Based on the priority handover strategy of channel monitoring in cellular radio system and the SMS which Attention instruction commands MODEM to receive in PDU format, we propose a self-testing approach defending against rogue base station hijacking of intelligent terminal. Extensive experiments have demonstrated the accuracy, effectiveness, and robustness of our approach.