| 1. |
- Atif, Yacine, 1967-, et al.
(author)
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Internet of Things data analytics for parking availability prediction and guidance
- 2020
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In: European transactions on telecommunications. - : Wiley-Blackwell Publishing Inc.. - 1124-318X .- 2161-3915 .- 2161-5748. ; 31
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Journal article (peer-reviewed)abstract
- Cutting-edge sensors and devices are increasingly deployed within urban areas to make-up the fabric of transmission control protocol/internet protocol con- nectivity driven by Internet of Things (IoT). This immersion into physical urban environments creates new data streams, which could be exploited to deliver novel cloud-based services. Connected vehicles and road-infrastructure data are leveraged in this article to build applications that alleviate notorious parking and induced traffic-congestion issues. To optimize the utility of parking lots, our proposed SmartPark algorithm employs a discrete Markov-chain model to demystify the future state of a parking lot, by the time a vehicle is expected to reach it. The algorithm features three modular sections. First, a search pro- cess is triggered to identify the expected arrival-time periods to all parking lots in the targeted central business district (CBD) area. This process utilizes smart-pole data streams reporting congestion rates across parking area junc- tions. Then, a predictive analytics phase uses consolidated historical data about past parking dynamics to infer a state-transition matrix, showing the transfor- mation of available spots in a parking lot over short periods of time. Finally, this matrix is projected against similar future seasonal periods to figure out the actual vacancy-expectation of a lot. The performance evaluation over an actual busy CBD area in Stockholm (Sweden) shows increased scalability capa- bilities, when further parking resources are made available, compared to a baseline case algorithm. Using standard urban-mobility simulation packages, the traffic-congestion-aware SmartPark is also shown to minimize the journey duration to the selected parking lot while maximizing the chances to find an available spot at the selected lot.
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| 2. |
- Abbas, Muhammad Tahir, et al.
(author)
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An adaptive approach to vehicle trajectory prediction using multimodel Kalman filter
- 2020
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In: European transactions on telecommunications. - : Wiley-Blackwell. - 1124-318X .- 2161-3915.
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Journal article (peer-reviewed)abstract
- With the aim to improve road safety services in critical situations, vehicle trajectory and future location prediction are important tasks. An infinite set of possible future trajectories can exit depending on the current state of vehicle motion. In this paper, we present a multimodel-based Extended Kalman Filter (EKF), which is able to predict a set of possible scenarios for vehicle future location. Five different EKF models are proposed in which the current state of a vehicle exists, particularly, a vehicle at intersection or on a curve path. EKF with Interacting Multiple Model framework is explored combinedly for mathematical model creation and probability calculation for that model to be selected for prediction. Three different parameters are considered to create a state vector matrix, which includes vehicle position, velocity, and distance of the vehicle from the intersection. Future location of a vehicle is then used by the software-defined networking controller to further enhance the safety and packet delivery services by the process of flow rule installation intelligently to that specific area only. This way of flow rule installation keeps the controller away from irrelevant areas to install rules, hence, reduces the network overhead exponentially. Proposed models are created and tested in MATLAB with real-time global positioning system logs from Jeju, South Korea.
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| 3. |
- Abrardo, A, et al.
(author)
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Network coding schemes for D2D communications based relaying for cellular coverage extension
- 2015
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In: European transactions on telecommunications. - : European transactions on Telecommunications. - 1124-318X .- 2161-3915. ; -
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Journal article (peer-reviewed)abstract
- Although network-assisted device-to-device (D2D) communications are known to improve the spectral and energy efficiency of proximal communications, the performance of cooperative D2D schemes in licenced spectrum is less understood when employed to extend the coverage of cellular networks. In this paper, we study the performance of D2D-based range extension in terms of sum rate and power efficiency when a relaying user equipment (UE) helps to improve the coverage for cell edge UEs. In our design, the relaying UE may have own traffic to transmit and receive to/from the cellular base station (BS) and can operate either in amplify-and-forward (AF) or decode-and-forward (DF) modes and can make use of either digital or analogue physical (PHY) layer network coding. In this rather general setting, we propose mode selection, resource allocation and power control schemes and study their performance by means of system simulations. We find that the performance of the DF scheme with network coding is superior both to the traditional cellular and the AF-based relaying schemes, including AF with two-slot or three-slot PHY layer network coding.
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| 4. |
- Athanasiou, George, et al.
(author)
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Design and implementation of distributed load balancing and fast handoff for wireless mesh networks
- 2015
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In: European transactions on telecommunications. - : Wiley. - 1124-318X .- 2161-3915. ; 26:4, s. 630-649
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Journal article (peer-reviewed)abstract
- The association/handoff procedures are very important towards achieving a balanced operation in 802.11-based wireless mesh networks. In this paper, we design and implement a cooperative association/handoff scheme, where stations share useful information, and handoff is executed in a seamless manner. Furthermore, we introduce a cross-layer load balancing mechanism that takes into account uplink and downlink channel conditions, routing performance and congestion control. The proposed heuristic algorithms are inspired by the rapidly designed cooperative protocols and control the communication load of each mesh access point in a distributed manner. We evaluate the performance of our mechanisms through OPNET () simulations and testbed experiments. Copyright (c) 2013 John Wiley & Sons, Ltd.
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| 5. |
- Athanasiou, George, et al.
(author)
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Dynamic Frequency Management in 802.11-based Multi-Radio Wireless Networks
- 2014
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In: European transactions on telecommunications. - : Wiley. - 1124-318X .- 2161-3915. ; 25:7, s. 752-768
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Journal article (peer-reviewed)abstract
- Efficient channel selection is essential in 802.11 mesh deployments, for minimising contention and interference among co-channel devices and thereby supporting a plurality of quality of service (QoS)-sensitive applications. A few protocols have been proposed for frequency allocation in such networks; however, they do not address the problem end-to-end. In this paper, we present a general formulation of the channel selection problem, taking into account the performance of both mesh access and mesh backhaul. Moreover, we propose a routing-aware channel selection protocol for wireless mesh networks (ARACHNE). ARACHNE is distributed in nature and motivated by our measurements on a wireless testbed. The main novelty of our protocol comes from adopting a metric that captures the end-to-end link loads across different routes in the network. ARACHNE prioritises the assignment of low-interference channels to links that (i) need to serve high-load aggregate traffic and/or (ii) already suffer significant levels of contention and interference. Our protocol takes into account the number of potential interfaces (radios) per device and allocates these interfaces in a manner that efficiently utilises the available channel capacity. We evaluate ARACHNE through extensive, trace-driven simulations, and we show the approaches to the optimal channel selection. We observe that our protocol improves the total network throughput, as compared to three other representative channel allocation approaches in literature.
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| 6. |
- Ben Slimane, Slimane
(author)
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MC-CDMA with Quadrature Spreading for Wireless Communication Systems
- 1998
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In: European transactions on telecommunications. - Milano : Assoc Elettrotecnica Ed Elettronica Italiana. - 1124-318X .- 2161-3915 .- 1541-8251. ; 9:4, s. 371-378
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Journal article (peer-reviewed)abstract
- MultiCarrier CDMA (MCCDMA) systems using the Orthogonal Frequency Division Division Multiple Access (OFDM) technique resolve the frequency se lectivity in multipath fading channels and have good spectral properties. The addition of a spread spectrum component to the OFDM introduces a frequency diversity gain that can combat deep multipath fading situations. In this paper a MCCDMA system operating over frequency selective, slowly fading channels is considered and its performance is studied analytically and by computer simulations. We consider the downlink of a cellular radio system where for each user a BPSK modulation and a quadrature (complex) spreading code is used. The spreading codes are arranged in a way that reduces the effect of the multipath fading channel and restores some of the orthogonality losses between users. The obtained results show considerable performance improvement compared to conventional OFDM and to MCCDMA that uses single spreading codes. The effect of frequency offsets on the system performance is also addressed in this paper. Its superior performance and low complexity receiver make MCCDMA with quadrature spreading codes suitable for future wireless communication systems to achieve the requirements of high quality services, high speed, and low costreceiver.
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| 7. |
- Ben Slimane, Slimane, et al.
(author)
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On the Capacity of CDMA with Linear Successive Interference Cancellation
- 2003
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In: European transactions on telecommunications. - : Wiley. - 1124-318X .- 2161-3915 .- 1541-8251. ; 14:6, s. 501-513
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Journal article (peer-reviewed)abstract
- Combined power control and interference cancellation in CDMA systems can be a very efficient resourcemanagement tool. While conventional power control tries to maintain equal received power or balancedsignal-to-interference ratio (SIR), successive interference cancellation (SIC) in multi-user detection (MUD)relies more on the disparities between the powers of the different users. The combination can save morepower into the system and thus a room for a better capacity. This paper investigates the interaction between power control and linear SIC in a single-rate CDMAsystem and its impact on the system capacity. The obtained results show that interference cancellation canimprove the capacity of CDMA and relax power control requirements. The full integration of power controland linear SIC detection is shown to provide excellent resource management in CDMA systems. Limitedinterference cancellation can be a good solution for CDMA systems as it provides considerable capacitygain with reduced complexity. An upper bound on the system capacity as a function of the cancellationparameters used along the different stages of the SIC detector is derived. Investigation of the optimumdecoding order is also provided in this paper.
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| 8. |
- Bergfeldt, Erik, et al.
(author)
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Real-time bandwidth measurements over mobile connections
- 2011
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In: European transactions on telecommunications. - : John Wiley and Sons. - 1124-318X .- 2161-3915. ; 22:6, s. 255-267
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Journal article (peer-reviewed)abstract
- The first study that investigates the characteristics of received probe packets and the reliability of bandwidth estimates when actively measuring the available bandwidth over radio interfaces in mobile communication networks is presented. Knowledge of available bandwidth is very useful in various contexts, e. g. in network management and adaptive streaming applications. Bandwidth measuring tools have so far primarily been designed for and evaluated in wired networks. However, such tools should also be examined in wireless networks since the use of, e. g., mobile broadband is rapidly increasing. The properties of wired and wireless links differ substantially, which affect the performance of the tools. We have made active-probing experiments over a high-speed downlink shared channel, which is used for High-Speed Downlink Packet Access (HSDPA) in the mobile communication technology UMTS, and over a forward traffic channel in CDMA2000 1xEV-DO. Both experiments were performed over commercial networks. They show that one cannot always expect uniform per-packet processing over the radio channel in mobile networks, which is expected by many probing tools. This reduces the reliability of the available-bandwidth estimates, however we suggest how this can be handled. Finally, the mobile-network measurements are compared to experiments performed in an IEEE 802.11 wireless LAN, where the radio channel does not create the same packet-processing behaviour. We also discuss the possibility of using the probe traffic for the purpose of identifying the communication technology at the bottleneck of the network path, assumed this is a wireless broadband link, by mapping specifications of standardised communication technologies to observed probe-traffic characteristics.
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| 9. |
- Berggren, Fredrik
(author)
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An error bound for moment matching methods of lognormal sum distributions
- 2005
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In: European transactions on telecommunications. - CHICHESTER : John Wiley & Sons, Ltd.. - 1124-318X .- 2161-3915 .- 1541-8251. ; 6:6, s. 573-577
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Journal article (peer-reviewed)abstract
- To evaluate the distribution function of a sum of lognormal random variables. it is common to use approximation methods based on moment matching. These include the classical and simple Fenton-Wilkinson method, which approximates the sum with a single lognormal variable, having the first two moments matched. In this letter, we give a closed-form bound for the error of the distribution function, resulting from moment matching methods. Numerical evaluation for a typical CDMA case, shows that the bound becomes tight for large processing gains. The error bound can also be used to find bounds on the outage probability.
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| 10. |
- Bohge, Mathias, et al.
(author)
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Optimal Soft Frequency Reuse and Dynamic Sub-carrier Assignments in Cellular OFDMA Networks
- 2010
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In: European transactions on telecommunications. - : Wiley. - 1124-318X .- 2161-3915. ; 21:8, s. 704-713
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Journal article (peer-reviewed)abstract
- Soft frequency reuse (SFR) is a common technique for co-channel interference (CCI) mitigation in cellular OFDMA networks. The performance of such networks significantly depends on the configuration of the power profiles that implement the soft frequency reuse patterns. In this paper, we investigate the performance of static soft frequency reuse by comparing it against the optimal case, in which a central entity optimally distributes power among the users of the network. It is shown that there is a significant performance gap between both approaches, which needs to be filled by adaptive SFR mechanisms. Moreover, we show that the achievable gain of static SFR is small in a system that is able to optimally decide on terminal/sub-carrier assignments.
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