| 1. |
- Björnson, Emil, Professor, 1983-, et al.
(författare)
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Designing Wireless Broadband Access for Energy Efficiency : Are Small Cells the Only Answer?
- 2015
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Ingår i: 2015 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATION WORKSHOP (ICCW). - : IEEE. - 9781467363051 ; , s. 136-141
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Konferensbidrag (refereegranskat)abstract
- The main usage of cellular networks has changed from voice to data traffic, mostly requested by static users. In this paper, we analyze how a cellular network should be designed to provide such wireless broadband access with maximal energy efficiency (EE). Using stochastic geometry and a detailed power consumption model, we optimize the density of access points (APs), number of antennas and users per AP, and transmission power for maximal EE. Small cells are of course a key technology in this direction, but the analysis shows that the EE improvement of a small-cell network saturates quickly with the AP density and then "massive MIMO" techniques can further improve the EE.
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| 2. |
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| 3. |
- Böhm, Annette, 1975-, et al.
(författare)
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Data age based retransmission scheme for reliable control data exchange in platooning applications
- 2015
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Ingår i: 2015 IEEE International Conference on Communication Workshop (ICCW). - Piscataway, NJ : IEEE Press. - 9781467363051 ; , s. 2412-2418
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Konferensbidrag (refereegranskat)abstract
- Recent advances in cooperative driving hold the potential to significantly improve safety, comfort and efficiency on our roads. Platooning of heavy vehicles, where automated or semi-automated driving allows minimal inter-vehicle gaps, has shown considerable reductions in fuel consumption. Although using the same wireless communication technology, a platoon differs from a VANET (Vehicular Ad-hoc NETwork) in several points. It is centralized in its nature, with a well-defined group leader, its topology is fairly stable and it has very challenging requirements on timeliness and reliability of its control data exchange. Therefore, the IEEE 802.11p protocol suite and its recently defined message types do neither support the needs of a platooning application nor take advantage of its properties. A platoons control loop must continuously be fed with fresh data, so the information age is an important parameter to be closely monitored. In this paper, we therefore propose a framework for centralized channel access and retransmission capabilities for safety critical inter-platoon control data based on the data age of earlier received messages. A simulation evaluation compares our solution to a) the decentralized, standard-compliant IEEE 802.11p MAC (Medium Access Control) method, and a time-slotted scheme b) with and c) without retransmissions and shows that the centralized, data age based retransmission scheme clearly outperforms its competitors in terms of maintained data age. © 2015 IEEE.
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| 4. |
- Campolo, Claudia, et al.
(författare)
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Service Discovery and Access in Vehicle-to-Roadside Multi-Channel VANETs
- 2015
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Ingår i: 2015 IEEE International Conference on Communication Workshop. - Piscataway, NJ : IEEE Press. - 9781467363051 ; , s. 2477-2482
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Konferensbidrag (refereegranskat)abstract
- A wide portfolio of safety and non-safety services will be provided to drivers and passengers on top of Vehicular Ad Hoc Networks (VANETs).Non-safety services are announced by providers, e.g., road-side units (RSUs), on a channel that is different from the one where the services are delivered. The dependable and timely delivery of the advertisement messages is crucial for vehicles to promptly discover and access the announced services in challenging vehicle-to-roadside scenarios, characterized by intermittent and short lived connectivity.In this paper, we present an analytical framework that models the service advertisement and access mechanisms in multichannel vehicular networks.The model accounts for dual-radio devices, and computes the mean service discovery time and the service channel utilization by considering the disruption periods due to the switching of the RSU from the advertising channel (where announcements are transmitted) to the advertised channel (where services are exchanged), under different channel and mobility conditions. It provides quick insights on parameter settings to allow providers to improve service provisioning. © 2015 IEEE
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| 5. |
- Chen, Jingjing, 1982, et al.
(författare)
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A data-rate adaptable modem solution for millimeter-wave wireless fronthaul networks
- 2015
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Ingår i: 2015 IEEE International Conference on Communication Workshop, ICCW 2015. - 2164-7038. - 9781467363051 ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- For dense small cell deployment in centralized baseband architecture, wireless fronthaul is a cost efficient and flexible alternative to fiber-based fronthaul links. Due to the available wide bandwidth, millimeter-wave technology is the most promising choice to realize multi-gigabit wireless transmission of the common public radio interface (CPRI). In this paper, we present a novel differential encoding scheme for differential quadrature phase-shift keying (D-QPSK) modulation, which enables data-rate adaptable CPRI transmission without modification of a standard receiver. A multi-rate D-QPSK modulator/demodulator (modem) is implemented and tested for data rates up to 10 Gbps, limited by the bandwidth of the microwave components in use. This modem is verified to fulfill the CPRI specifications with respect to multi-rate, low latency and high system performance. Therefore, it is proposed for the implementation of wireless CPRI links at millimeter-wave bands.
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| 6. |
- Chen, Lei, et al.
(författare)
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Design of in-building distributed antenna systems: mathematical models and efficient algorithms
- 2015
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Ingår i: 2015 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATION WORKSHOP. - : IEEE. - 9781467363051 ; , s. 1497-1502
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Konferensbidrag (refereegranskat)abstract
- In order to provide sufficient coverage and capacity for indoor users, in-building distributed antenna system (IB-DAS) has been considered. A passive IB-DAS deploys distributed antennas inside the building and connects the antennas to a base station (BS) through coaxial cables and power equipment. Power is distributed from the BS to each of the antennas. We consider an optimal design of passive IB-DAS with the target to minimize the cable usage, together with the consideration of power distribution. We decompose the problem into two sub-problems, namely the topological design and the equipment selection. Mixed integer linear models are developed for solving the sub-problems. Local search is designed to combine the sub-problems and balance their objectives. Application over realistic IB-DAS deployment and comparison with previous studies demonstrate the effectiveness of the algorithm.
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| 7. |
- Chu, Thi My Chinh, et al.
(författare)
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Channel Reservation for Dynamic Spectrum Access of Cognitive Radio Networks with Prioritized Traffic
- 2015
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Ingår i: 2015 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATION WORKSHOP. - : IEEE Communications Society. - 9781467363051 ; , s. 883-888
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Konferensbidrag (refereegranskat)abstract
- In this paper, we propose a strategy to coordinate the dynamic spectrum access (DSA) of different types of traffic. It is assumed that the DSA assigns spectrum bands to three kinds of prioritized traffic, the traffic of the primary network, the Class 1 traffic and Class 2 traffic of the secondary network. Possessing the licensed spectrum, the primary traffic has the highest access priority and can access the spectrum bands at anytime. The secondary Class 1 traffic has higher priority compared to secondary Class 2 traffic. In this system, a channel reservation scheme is deployed to control spectrum access of the traffic. Specifically, the optimal number of reservation channels is applied to minimize the forced termination probability of the secondary traffic while satisfying a predefined blocking probability of the primary network. To investigate the system performance, we model state transitions of the DSA as a multi-dimensional Markov chain with three-state variables representing the number of primary, Class 1, and Class 2 packets in the system. Based on this chain, important performance measures, i.e., blocking probability and forced termination probability are derived for the Class 1 and Class 2 secondary traffic.
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| 8. |
- Cippitelli, E., et al.
(författare)
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Time synchronization and data fusion for RGB-Depth cameras and inertial sensors in AAL applications
- 2015
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Ingår i: 2015 IEEE International Conference on Communication Workshop, ICCW 2015. - : IEEE conference proceedings. - 9781467363051 ; , s. 265-270
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Konferensbidrag (refereegranskat)abstract
- Ambient Assisted Living applications often need to integrate data from multiple sensors, to provide consistent information on the observed phenomena. Data fusion based on samples from several sensors requires accurate time synchronization with sufficient resolution, depending on the sensor sampling frequency. This work presents a technical platform for the efficient and accurate synchronization of the data captured from RGB-Depth cameras and wearable inertial sensors, that can be integrated in AAL solutions. A case study of sensor data fusion for Timed Up and Go test is also presented and discussed.
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| 9. |
- Farhadi, Hamed, 1983-, et al.
(författare)
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Pilot-assisted opportunistic user scheduling for wireless multi-cell networks
- 2015
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Ingår i: IEEE International Conference on Communications. - : IEEE. - 9781467363051
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Konferensbidrag (refereegranskat)abstract
- We consider downlink transmission in multi-cell wireless networks where in each cell one base station is serving multiple mobile terminals. There is no a priori channel state information (CSI) available at base stations and mobile terminals. We propose a low-complexity pilot-assisted opportunistic user scheduling (PAOUS) scheme. The proposed scheme operates in four subsequent phases: channel training; feedback transmission; user scheduling; and data transmission. We deploy an orthogonal pilot-assisted channel training scheme for acquiring CST at mobile terminals. Consequently, each mobile terminal obtains a noisy estimation of the corresponding local CST (i.e. channel gains from base stations to the mobile terminal). Then, it makes a local decision based on the estimated channel gains of the interfering links (i.e. the links between base stations in neighboring cells and the mobile terminal) and sends a one-bit feedback signal to the base station of the corresponding cell. Each base station schedules one mobile terminal for communication. We compute the achievable rate region and the achievable degrees of freedom (DoF) of the proposed transmission scheme. Our results show that in a multi-cell network with K base stations and coherence time T, the total DoF K-opt (1 - K-opt/T) is achievable given that the number of mobile terminals in each cell scales proportional to signal-to-noise-ratio. Since limited radio resources are available, only a subset of base stations should be activated, where the optimum number of active base stations is K-opt = min {K, T/2}. This recommends that in large networks (K > T/2), select only a subset of the base stations to be active and perform the PAOUS scheme within the cells associated to these base stations. Our results reveal that, even with single antenna at base stations and no a priori CSI at terminals, a non-trivial DoF gain can be achieved. We also investigate the power allocation between channel training and data transmission phases. Our study shows that in large networks (many base stations) more power should be allocated to channel training while in dense networks (many mobile terminals in each cell) more power should be allocated for data transmission.
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| 10. |
- Garcia, Gabriel, 1985, et al.
(författare)
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Joint scheduling and localization in UWB networks
- 2015
-
Ingår i: 2015 IEEE International Conference on Communication Workshop, ICCW 2015. - 9781467363051 ; , s. 724-729
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Konferensbidrag (refereegranskat)abstract
- Ultra-wide bandwidth (UWB) systems allow for accurate localization to tackle and complement the GPS-aided solutions, which are impractical in weak signal environments. We consider the problem of fast link scheduling in the medium access control (MAC) layer for UWB localization. We present an optimization strategy to perform robust ranging scheduling with localization constraints. Given the complexity of the optimal strategy, two different MAC-aware link selection heuristics are also proposed. Our results show that significant MAC delay reductions are possible through the use of simple local heuristics. © 2015 IEEE.
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| 11. |
- Gezici, Sinan, et al.
(författare)
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Optimal Jamming of Wireless Localization Systems
- 2015
-
Ingår i: 2015 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATION WORKSHOP. - : IEEE. - 9781467363051 ; , s. 877-882
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Konferensbidrag (refereegranskat)abstract
- In this study, optimal jamming of wireless localization systems is investigated. Two optimal power allocation schemes are proposed for jammer nodes in the presence of total and peak power constraints. In the first scheme, power is allocated to jammer nodes in order to maximize the average Cramer-Rao lower hound (CRLB) of target nodes whereas in the second scheme the power allocation is performed for the aim of maximizing the minimum CRLB of target nodes. Both schemes are formulated as linear programs, and a closed-form expression is obtained for the first scheme. Also, the full total power utilization property is specified for the second scheme. Simulation results are presented to investigate perlbrmance of the proposed schemes.
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| 12. |
- Girnyk, Maksym, et al.
(författare)
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MIMO wiretap channels with randomly located eavesdroppers : Large-system analysis
- 2015
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Ingår i: 2015 IEEE International Conference on Communication Workshop, ICCW 2015. - : IEEE conference proceedings. - 9781467363051 ; , s. 480-484
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Konferensbidrag (refereegranskat)abstract
- Security issues in wireless networks have become a subject of growing interest in recent years due to the broadcast nature of wireless channels. In this paper, we investigate secure communication over a multi-antenna wiretap channel in the presence of randomly distributed eavesdroppers. In the fast fading environment, the overall performance of this channel is traditionally characterized by the ergodic secrecy capacity, which, in general, cannot be derived explicitly. Nevertheless, based on the assumption that the numbers of antennas at legitimate terminals and the number of eavesdroppers grow large without bound, we derive a deterministic approximation of an achievable ergodic secrecy rate for arbitrary inputs. In addition, we characterize the secrecy rates for practically relevant separate-decoding scheme at the receiver. We validate the proposed large-system approximation through numerical simulations and observe a good match with the actual secrecy rates. Finally, we also analyze some interesting behavior of the secrecy rates in the given scenario depending on the geometry of the nodes.
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| 13. |
- Hoang, L. -N, et al.
(författare)
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A framework for reliable exchange of periodic and event-driven messages in platoons
- 2015
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Ingår i: 2015 IEEE International Conference on Communication Workshop, ICCW 2015. - Piscataway : IEEE conference proceedings. - 9781467363051 ; , s. 2471-2476
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Konferensbidrag (refereegranskat)abstract
- Platooning is widely considered a promising approach to decrease fuel consumption by reducing the air drag. However, in order to achieve the benefits of aerodynamic efficiency, the inter-vehicle distances must be kept short. This implies that the intra-platoon communication must not only be reliable but also able to meet strict timing deadlines. In this paper, we propose a framework that reliably handles the co-existence of both time-triggered and event-driven control messages in platooning applications and we derive an efficient message dissemination technique. We propose a semi-centralized time division multiple access (TDMA) approach, which e.g., can be placed on top of the current standard IEEE 802.11p and we evaluate the resulting error probability and delay, when using it to broadcast periodic beacons and disseminating event-driven messages within a platoon. Simulation results indicate that the proposed dissemination policy significantly enhances the reliability for a given number of available time-slots, or alternatively, reduces the delay, in terms of time-slots, required to achieve a certain target error probability, without degrading the performance of co-existing time-triggered messages.
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| 14. |
- Hossain, M. M. A., et al.
(författare)
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Energy saving market for mobile operators
- 2015
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Ingår i: 2015 IEEE International Conference on Communication Workshop, ICCW 2015. - : IEEE conference proceedings. - 9781467363051 ; , s. 2856-2861
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Konferensbidrag (refereegranskat)abstract
- Ensuring seamless coverage accounts for the lion's share of the energy consumed in a mobile network. Overlapping coverage of three to five mobile network operators (MNOs) results in enormous amount of energy waste which is avoidable. The traffic demands of the mobile networks vary significantly throughout the day. As the offered load for all networks are not same at a given time and the differences in energy consumption at different loads are significant, multi-MNO capacity/coverage sharing can dramatically reduce energy consumption of mobile networks and provide the MNOs a cost effective means to cope with the exponential growth of traffic. In this paper, we propose an energy saving market for a multi-MNO network scenario. As the competing MNOs are not comfortable with information sharing, we propose a double auction clearinghouse market mechanism where MNOs sell and buy capacity in order to minimize energy consumption. In our setting, each MNO proposes its bids and asks simultaneously for buying and selling multi-unit capacities respectively to an independent auctioneer, i.e., clearinghouse and ends up either as a buyer or as a seller in each round. We show that the mechanism allows the MNOs to save significant percentage of energy cost throughout a wide range of network load. Different than other energy saving features such as cell sleep or antenna muting which can not be enabled at heavy traffic load, dynamic capacity sharing allows MNOs to handle traffic bursts with energy saving opportunity.
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| 15. |
- Ivanov, Mikhail, 1986, et al.
(författare)
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All-to-all Broadcast for Vehicular Networks Based on Coded Slotted ALOHA
- 2015
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Ingår i: IEEE International Conference on Communication Workshop, ICCW 2015, London, UK, June 2015. - 9781467363051 ; , s. 2046-2050
-
Konferensbidrag (refereegranskat)abstract
- We propose an uncoordinated all-to-all broadcast protocol for periodic messages in vehicular networks based on coded slotted ALOHA (CSA). Unlike classical CSA, each user acts as both transmitter and receiver in a half-duplex mode. As in CSA, each user transmits its packet several times. The half-duplex mode gives rise to an interesting design trade-off: the more the user repeats its packet, the higher the probability that this packet is decoded by other users, but the lower the probability for this user to decode packets from others. We compare the proposed protocol with carrier sense multiple access with collision avoidance, currently adopted as a multiple access protocol for vehicular networks. The results show that the proposed protocol greatly increases the number of users in the network that reliably communicate with each other. We also provide analytical tools to predict the performance of the proposed protocol.
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| 16. |
- Jacobsson, Sven, 1990, et al.
(författare)
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One-Bit Massive MIMO: Channel Estimation and High-Order Modulations
- 2015
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Ingår i: 2015 IEEE International Conference on Communication Workshop, ICCW 2015. - 9781467363051 ; , s. 1304-1309
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Konferensbidrag (refereegranskat)abstract
- We investigate the information-theoretic throughout achievable on a fading communication link when the receiver is equipped with one-bit analog-to-digital converters (ADCs). The analysis is conducted for the setting where neither the transmitter nor the receiver have a priori information on the realization of the fading channels. This means that channel-state information needs to be acquired at the receiver on the basis of the one-bit quantized channel outputs. We show that least-squares (LS) channel estimation combined with joint pilot and data processing is capacity achieving in the single-user, single-receive-antenna case. We also investigate the achievable uplink throughput in a massive multiple-input multiple-output system where each element of the antenna array at the receiver base-station feeds a one-bit ADC. We show that LS channel estimation and maximum-ratio combining are sufficient to support both multiuser operation and the use of high-order constellations. This holds in spite of the severe nonlinearity introduced by the one-bit ADCs.
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| 17. |
- Krishnan, Rajet, 1982, et al.
(författare)
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Large-Scale Analysis of Linear Massive MIMO Precoders in the Presence of Phase Noise
- 2015
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Ingår i: 2015 IEEE International Conference on Communication Workshop. - 9781467363051 ; , s. 1172-1177
-
Konferensbidrag (refereegranskat)abstract
- We study the impact of phase noise on the downlink performance of a multi-user multiple-input multiple-output system, where the base station (BS) employs a large number of transmit antennas $M$. We consider a setup where the BS employs $M_{\mr{osc}}$ free-running oscillators, and $M/M_{\mr{osc}}$ antennas are connected to each oscillator. For this configuration, we analyze the impact of phase noise on the performance of regularized zero-forcing (RZF) precoding, when $M$ and the number of users $K$ are asymptotically large, while the ratio $M/K=\beta$ is fixed. We analytically show that the impact of phase noise on the signal-to-interference-plus-noise ratio (SINR) can be quantified as an effective reduction in the quality of the channel state information available at the BS when compared to a system without phase noise. As a consequence, we observe that as $M_{\mr{osc}}$ increases, the SINR of the RZF precoder degrades as the interference power increases, and the desired signal power decreases. On the other hand, the variance of the random phase variations caused by the BS oscillators reduces with increasing $M_{\mr{osc}}$. Through simulations, we verify our analytical results, and study the performance of the RZF precoder for different phase noise and channel noise variances.
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| 18. |
- Larsson, Marcus, 1979-, et al.
(författare)
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Curvature based Antenna Selection Method Evaluated Using the Data Age Metric and V2V Measurements
- 2015
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Ingår i: 2015 IEEE International Conference on Communication Workshop (ICCW). - Piscataway, NJ : IEEE Press. - 9781467363051 ; , s. 2356-2362
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Konferensbidrag (refereegranskat)abstract
- In this paper, we compare a method for selecting transmission antenna based on road curvature to a method based on periodically alternating between left and right hand side transmission antennas. Both methods aim to improve the success rate for communication between participants in a platoon of vehicles. Moreover, we propose the data age metric for online use as input to the algorithm controlling the inter-vehicle distance in platooning, e.g. to decide appropriate gap between the vehicles depending on the V2V communication quality. The methods have been evaluated through V2V communication measurements performed using heavy duty vehicles on public highway. We show that, when using the curvature-based method, a 150 ms data age deadline is only missed approximately half as often compared to when periodically alternating between left and right hand side transmission antennas. The methods have also been compared for different antenna combinations. © 2015 IEEE
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| 19. |
- Laya, Andres, et al.
(författare)
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Massive access in the Random Access Channel of LTE for M2M communications : An energy perspective
- 2015
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Ingår i: 2015 IEEE International Conference on Communication Workshop, ICCW 2015. - : IEEE conference proceedings. - 9781467363051 ; , s. 1452-1457
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Konferensbidrag (refereegranskat)abstract
- The capacity limits of the Random Access Channel (RACH) of Long Term Evolution (LTE) for highly dense Machine-to-Machine communications are studied in this paper. We consider the case study when a high number of devices attempt to transmit information to the same base station in a very short period of time. Simulations have been performed considering several parameter configurations related to the random access procedure of LTE. The energy consumption is used as a primordial metric to compare any improvement regarding the random access procedure in future releases, in order to evaluate the impact on the battery lifetime of autonomous devices.
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| 20. |
- Lemic, Filip, et al.
(författare)
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Web-based platform for evaluation of RF-based indoor localization algorithms
- 2015
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Ingår i: 2015 IEEE International Conference on Communication Workshop, ICCW 2015. - : Institute of Electrical and Electronics Engineers Inc.. - 9781467363051 ; , s. 834-840
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Konferensbidrag (refereegranskat)abstract
- The experimental efforts for optimizing the performance of RF-based indoor localization algorithms for specific environments and scenarios is time consuming and costly. In this work, we address this problem by providing a publicly accessible platform for streamlined experimental evaluation of RF-based indoor localization algorithms, without the need of a physical testbed infrastructure. We also offer an extensive set of raw measurements that can be used as input data for indoor localization algorithms. The datasets are collected in multiple testbed environments, with various densities of measurement points, using different measuring devices and in various scenarios with controlled RF interference. The platform encompasses two core services: one focused on storage and management of raw data, and one focused on automated calculation of metrics for performance characterization of localization algorithms. Tools for visualization of the raw data, as well as software libraries for convenient access to the platform from MATLAB and Python, are also offered. By contrasting its fidelity and usability with respect to remote experiments on dedicated physical testbed infrastructure, we show that the virtual platform produces comparative performance results while offering significant reduction in the complexity, time and labor overheads. © 2015 IEEE.
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| 21. |
- Lin, P. -H, et al.
(författare)
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Multi-phase transmission for secure cognitive radio networks
- 2015
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Ingår i: 2015 IEEE International Conference on Communication Workshop, ICCW 2015. - : IEEE conference proceedings. - 9781467363051 ; , s. 475-479
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Konferensbidrag (refereegranskat)abstract
- In this paper we study secure communications with weak secrecy constraint in a cognitive radio channel, where the secondary receiver is treated as a potential eavesdropper with respect to the primary transmission. The primary's secrecy rate and the transmission scheme should be kept unchanged whether the secondary users transmit or not. We derive the achievable rate of the discrete memoryless multi-phase cognitive channel. To against the information leakage due to the use of Gelfand-Pinsker coding at the secondary transmitter, we derive the corresponding constraints to guarantee the primary's secure transmission. We then specialize the results to the additive white Gaussian noise channels. Numerical results show the advantages of using the proposed multiple-phase transmission scheme over the traditional ones without the additional phase.
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| 22. |
- Lyamin, Nikita, 1989-, et al.
(författare)
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Does ETSI beaconing frequency control provide cooperative awareness?
- 2015
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Ingår i: 2015 IEEE International Conference on Communication Workshop (ICCW). - Piscataway, NJ : IEEE Press. - 9781467363051 ; , s. 2393-2398
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Konferensbidrag (refereegranskat)abstract
- Platooning is an emergent vehicular application aiming at increasing road safety, efficiency and driving comfort. The cooperation between the vehicles in a platoon is achieved by the frequent exchange of periodic broadcast Cooperative Awareness Messages (CAMs) also known as beacons. CAM triggering conditions are drafted in the standard ETSI EN 302 637–2 and are based on the dynamics of an originating vehicle. These conditions are checked repeatedly with a certain sampling rate. We have discovered that the improper choice of the sampling rate value may increase the number of collisions between CAMs at the IEEE 802.11p medium access control layer and, therefore, diminish the efficiency of beaconing in a platoon. © 2015 IEEE
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| 23. |
- Nguyen, D. K., et al.
(författare)
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RF energy harvesting two-way cognitive DF relaying with transceiver impairments
- 2015
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Ingår i: 2015 IEEE International Conference on Communication Workshop, ICCW 2015. - 9781467363051 ; , s. 1970 - 1975
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Konferensbidrag (refereegranskat)abstract
- This paper analyzes the impact of transceiver impairments on outage probability (OP) and throughput of decode-and-forward two-way cognitive relay (TWCR) networks, where the relay is self-powered by harvesting energy from the transmitted signals. We consider two bidirectional relaying protocols namely, multiple access broadcast (MABC) protocol and time division broadcast (TDBC) protocol, as well as, two power transfer policies namely, dual-source (DS) energy transfer and single-fixed-source (SFS) energy transfer. Closed-form expressions for OP and throughput of the network are derived in the context of delay-limited transmission. Numerical results corroborate our analysis, thereby we can quantify the degradation of OP and throughput of TWCR networks due to transceiver hardware impairments. Under the specific parameters, our results indicate that the MABC protocol achieves asymptotically a higher throughput by 0.65 [bits/s/Hz] than the TDBC protocol, while the DS energy transfer scheme offers better performance than the SFS policy for both relaying protocols. © 2015 IEEE.
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| 24. |
- Ni, Y., et al.
(författare)
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Beamforming and interference cancellation schemes for D2D communications
- 2015
-
Ingår i: 2015 IEEE International Conference on Communication Workshop, ICCW 2015. - 9781467363051 ; , s. 608-613
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Konferensbidrag (refereegranskat)abstract
- We investigate device-to-device (D2D) communication underlaying cellular networks with M-antenna base stations. We consider both beamforming (BF) and interference cancellation (IC) strategies under quantized channel state information (CSI), as well as, perfect CSI. We derive tight closed-form approximations of the ergodic achievable rate which hold for arbitrary transmit power, location of users and number of antennas. Based on these approximations, we derive insightful asymptotic expressions for three special cases namely high signal-to-noise (SNR), weak interference, and large M. In particular, we show that in the high SNR regime a ceiling effect exists which depends on the received signal-to-interference ratio and the number of antennas. Moreover, the achievable rate scales logarithmically with M. The ergodic achievable rate is shown to scale logarithmically with SNR and the antenna number in the weak interference case. When the BS is equipped with large number of antennas, we find that the ergodic achievable rate under quantized CSI reaches a saturated value, whilst it scales as log2M under perfect CSI.
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| 25. |
- Shahmansoori, A., et al.
(författare)
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Robust power allocation for OFDM wireless network localization
- 2015
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Ingår i: 2015 IEEE International Conference on Communication Workshop, ICCW 2015. - 9781467363051 ; , s. 718-723
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Konferensbidrag (refereegranskat)abstract
- Reliable and accurate localization of users is critical for many applications in wireless networks. In range-based localization, the position of a node (agent) can be estimated using distance measurements to nodes with known positions (anchors). Optimal power allocation of the anchors reduces positioning error and improves network lifetime and throughput. We formulate and solve a robust power allocation optimization problem with a constraint on the localization accuracy for multicast and unicast orthogonal frequency division multiplexing signals. The localization accuracy is expressed in terms of the expected squared position error bound, accounting for uncertainties in the wireless channel as well as in the agents' positions. Simulation results show that robust power allocation improves localization accuracy compared to non-robust power allocation, with only a limited power penalty. © 2015 IEEE.
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| 26. |
- Song, K., et al.
(författare)
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Performance analysis of relay-aided heterogeneous networks with interference cancellation
- 2015
-
Ingår i: 2015 IEEE International Conference on Communication Workshop, ICCW 2015. - : IEEE conference proceedings. - 9781467363051 ; , s. 985-990
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Konferensbidrag (refereegranskat)abstract
- We investigate the downlink performance of relay-aided heterogeneous networks (HetNet). An interference cancellation scheme employed at macro base stations is first proposed based on the cancellation of cross-tier interference from the macro base station to small cell users. Then, we derive the expressions of the probability density function (PDF) and cumulative distribution function (CDF) of the received SINRs of both macro and small cell users, and provide the closed-form average bit error rate (BER) and outage probability of the system. Through the derivation and simulation, we show the overall performance improvement of HetNet with interference cancellation in mathematical expression. The numerical results closely follow our analysis.
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| 27. |
- Tragos, Elias Z., et al.
(författare)
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An IoT based Intelligent Building Management System for Ambient Assisted Living
- 2015
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Ingår i: 2015 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATION WORKSHOP. - : IEEE. - 9781467363051 ; , s. 246-252
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Konferensbidrag (refereegranskat)abstract
- Ambient Assisted Living (AAL) describes an ICT based environment that exposes personalized and context-aware intelligent services, thus creating an appropriate experience to the end user to support independent living and improvement of the everyday quality of life of both healthy elderly and disabled people. The social and economic impact of AAL systems have boosted the research activities that combined with the advantages of enabling technologies such as Wireless Sensor Networks (WSNs) and Internet of Things (IoT) can greatly improve the performance and the efficiency of such systems. Sensors and actuators inside buildings can create an intelligent sensing environments that help gather realtime data for the patients, monitor their vital signs and identify abnormal situations that need medical attention. AAL applications might be life critical and therefore have very strict requirements for their performance with respect to the reliability of the devices, the ability of the system to gather data from heterogeneous devices, the timeliness of the data transfer and their trustworthiness. This work presents the functional architecture of SOrBet (Marie Curie IAPP project) that provides a framework for interconnecting efficiently smart devices, equipping them with intelligence that helps automating many of the everyday activities of the inhabitants. SOrBet is a paradigm shift of traditional AAL systems based on a hybrid architecture, including both distributed and centralized functionalities, extensible, self-organising, robust and secure, built on the concept of "reliability by design", thus being capable of meeting the strict Quality of Service (QoS) requirements of demanding applications such as AAL.
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| 28. |
- Wanlu, Sun, 1986, et al.
(författare)
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Resource Sharing and Power Allocation for D2D-based Safety-Critical V2X Communications
- 2015
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Ingår i: IEEE ICC 2015 Workshop. - : IEEE. - 9781467363051 ; , s. 2399-2405
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Konferensbidrag (refereegranskat)abstract
- Deploying direct device-to-device (D2D) links is considered an enabler for V2X applications, with intra-cell interference and stringent latency and reliability requirements as challenging issues.We investigate the radio resource management problem for D2D-based safety-critical V2X communications. Firstly, we analyze and transform the V2X latency and reliability requirements into mathematical forms that are computable using only slowly varying channel information. Secondly, we propose a problem formulation fulfilling the requirements of V2X, where resource sharing can take place not only between vehicles and cellular users but also among different vehicles. Moreover, a Resource Block Sharing and Power Allocation (RBSPA) algorithm is proposed to solve this problem. Finally, simulations are presented that indicate promising performance of the proposed RBSPA scheme.
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