| 1. |
- Araújo, Marco, et al.
(författare)
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A Utility Based Price Model for High Capacity Rural Networks in the European Union
- 2018
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Ingår i: 2018 IEEE 29th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC). - : IEEE. - 9781538660102 - 9781538660096 ; , s. 253-258
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Konferensbidrag (refereegranskat)abstract
- The European Union has been battling against the digital divide for several decades now when trying to mitigate the risk of social exclusion arising from the lack of broadband access, preventing citizens from full social and economic participation in the society. This has been done in the past by ensuring that a minimum set of services would be available to all end-users at an affordable price. However, various aspects of the rapid advances in technology, market developments and changes in user demand as well as the evolution of the telecommunications infrastructure (5G, IoT, Cloud, gigabit access, etc) increase the risk that citizens of rural areas are facing a severe risk of digital exclusion. To avoid this risk, the concept of subsidised rural networks was created by the European Commission. The idea as such is laudable, but the price tag remains unknown, which severely violates its implementability. In this article, based on the actual cost in a subsidised, but competitive, environment, we suggest a novel approach to realistically determine fair end-user's prices.
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| 2. |
- Araújo, Marco, et al.
(författare)
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Rural Networks Cost Comparison Between 5G (Mobile) and FTTx (Fixed) Scenarios
- 2018
-
Ingår i: 2018 IEEE 29th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC). - : IEEE. - 9781538660102 - 9781538660096 ; , s. 259-264
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Konferensbidrag (refereegranskat)abstract
- In this article we simulate the infrastructure costs for very fast networks in rural areas. FTTH technology has been around for at least a decade, but two brand new technologies are expected to launch commercially in the next couple of years: 5G and G. Fast. This could have a strong impact on infrastructure costs and the fulfilment of the European Union, rural coverage objectives. 5G seems to be very promising since LTE is not a reasonable solution for very fast networks. FTTC has so far not been a valid alternative, since for the last mile, the only options for FTTC has been ADSL and VDSL, which however cannot reach very fast data rates. G.Fast is three times faster than VDSL and has the advantage, comparing to FTTH, that the last mile infrastructure is already build in the form of copper local loop.
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| 3. |
- Grazia, Carlo Augusto, et al.
(författare)
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Adapting TCP Small Queues for IEEE 802.11 Networks
- 2018
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Ingår i: 2018 IEEE 29Th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC). - : IEEE. - 9781538660096 - 9781538660102
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Konferensbidrag (refereegranskat)abstract
- In recent years, the Linux kernel has adopted an algorithm calledTCP Small Queues (TSQ) for reducing queueing latency by controlling buffering in the networking stack.This solution consists of a back-pressure mechanism that limitsthe number of TCP segments within the sender TCP/IP stack, waitingfor packets to actually be transmitted onto the wire beforeenqueueing further segments.Unfortunately, TSQ prevents the frameaggregation mechanism in the IEEE 802.11n/ac standards from achieving itsmaximum aggregation, because not enough packets are available in the queue to buildaggregates from, which severely limits achievable throughput over wirelesslinks.This paper demonstrates this limitation of TSQ in wireless networks and proposesControlled TSQ (CoTSQ), a solution that improves TSQ so that it controls the amountof data buffered while allowing the IEEE 802.11n/ac aggregation logic to fullyexploit the available channel and achieve high throughput. Results on a real testbed show that CoTSQ leadsto a doubling of throughput on 802.11n and up to an order of magnitudeimprovement in 802.11ac networks, with a negligible latency increase.
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| 4. |
- Hu, Sha, et al.
(författare)
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User Assignment with Distributed Large Intelligent Surface (LIS) Systems
- 2018
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Ingår i: 2018 IEEE 29th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC). - 9781538660096 - 9781538660102
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Konferensbidrag (refereegranskat)abstract
- In this paper, we consider a wireless communication system where a large intelligent surface (LIS) is deployed comprising a number of small and distributed LIS-Units. Each LIS-Unit has a separate signal process unit (SPU) and is connected to a central process unit (CPU) that coordinates the behaviors of all the LIS-Units. With such a LIS system, we consider the user assignments both for sum-rate and minimal user-rate maximizations. That is, assuming $M$ LIS-Units deployed in the LIS system, the objective is to select $K$ ($K\!\leq\!M$) best LIS-Units to serve $K$ autonomous users simultaneously. Based on the nice property of effective inter-user interference suppression of the LIS-Units, the optimal user assignments can be effectively found through classical linear assignment problems (LAPs) defined on a bipartite graph. To be specific, the optimal user assignment for sum-rate and user-rate maximizations can be solved by linear sum assignment problem (LSAP) and linear bottleneck assignment problem (LBAP), respectively. The elements of the cost matrix are constructed based on the received signal strength (RSS) measured at each of the $M$ LIS-Units for all the $K$ users. Numerical results show that, the proposed user assignments are close to optimal user assignments both under line-of-sight (LoS) and scattering environments.
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| 5. |
- Nguyen, Van-Giang, 1989-, et al.
(författare)
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On Load Balancing for a Virtual and Distributed MME in the 5G Core
- 2018
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Ingår i: 2018 IEEE 29th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC). - : IEEE. - 9781538660102 - 9781538660096
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Konferensbidrag (refereegranskat)abstract
- In this paper, we aim at tackling the scalability problem of the Mobility Management Entity (MME), which plays a crucial role of handling control plane traffic in the current 4G Evolved Packet Core as well as the next generation mobile core, 5G. One of the solutions to this problem is to virtualize the MME by applying Network Function Virtualization principles and then deploy it as a cluster of multiple virtual MME instances (vMMEs) with a front-end load balancer. Although several designs have been proposed, most of them assume the use of simple algorithms such as random and round-robin to balance the incoming traffic without any performance assessment. To this end, we implemented a weighted round robin algorithm which takes into account the heterogeneity of resources such as the capacity of vMMEs. We compare this algorithm with a random and a round-robin algorithm under two different system settings. Experimental results suggest that carefully selected load balancing algorithms can significantly reduce the control plane latency as compared to simple random or round-robin schemes.
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| 6. |
- Apelfröjd, Rikke, 1986-, et al.
(författare)
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Kalman Smoothing for Irregular Pilot Patterns : A Case Study for Predictor Antennas in TDD Systems
- 2018
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Ingår i: 2018 IEEE 29TH ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS (PIMRC). - : IEEE. - 9781538660096
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Konferensbidrag (refereegranskat)abstract
- For future large-scale multi-antenna systems, channel orthogonal downlink pilots are not feasible due to extensive overhead requirements. Instead, channel reciprocity can be utilized in time division duplex (TDD) systems so that the downlink channel estimates can be based on pilots transmitted during the uplink. User mobility affects the reciprocity and makes the channel state information outdated for high velocities and/or long downlink subframe durations. Channel extrapolation, e.g. through Kalman prediction, can reduce the problem but is also limited by high velocities and long downlink subframes. An alternative solution has been proposed where channel predictions are made with the help of an extra antenna, e.g. on the roof of a car, so called predictor antenna, with the primary objective to measure the channel at a position that is later encountered by the rearward antenna(s). The predictor antenna is not directly limited by high velocities and allows the channel in the downlinks to be interpolated rather than extrapolated. One remaining challenge here is to obtain a good interpolation of the uplink channel estimate, since a sequence of uplink reference signals (pilots) will be interrupted by downlink subframes. We here evaluate a Kalman smoothing estimate of the downlink channels and compare it to a cubic spline interpolation. These results are also compared to results where uplink channels are estimated through Kalman filters and predictors. Results are based on measured channels and show that with Kalman smoothing, predictor antennas can enable accurate channel estimates for a longer downlink period at vehicular velocities. The gaps in the uplink pilot stream, due to downlink subframes, can have durations that correspond to a vehicle movement of up to 0.75 carrier wavelengths in space, for Rayleigh-like non-line-of-sight fading.
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| 7. |
- Aslam, Mohammed Zahid, et al.
(författare)
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Large-scale Massive MIMO Network Evaluation Using Ray-based Deterministic Simulations
- 2018
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Ingår i: 2018 IEEE 29TH ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR AND MOBILE RADIO COMMUNICATIONS (PIMRC). - : IEEE. - 9781538660096
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Konferensbidrag (refereegranskat)abstract
- Large-scale massive MIMO network deployments can provide higher spectral efficiency and better coverage for future communication systems like 5G. Due to the large number of antennas at the base station, the system achieves stable channel quality and spatially separable channels to the different users. In this paper, linear, planar, circular and cylindrical arrays are used in the evaluation of a large-scale multi-cell massive MIMO network. The system-level performance is predicted using two different kinds of channel models. First, a ray-based deterministic tool is utilized in a real North American city environment. Second, an independent and identically distributed (i.i.d.) Rayleigh fading channel model is considered, as often used in previously published massive MIMO studies. The analysis is conducted in a 16-macro-cell network with outdoor and randomly distributed users. It is shown that the array configuration has a large impact on the throughput statistics. Although the system level performance with i.i.d. Rayleigh fading can be close to the deterministic prediction in some situations (e.g., with large linear arrays), significant differences are noticed when considering other types of arrays.
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| 8. |
- Aydogdu, Canan, 1978, et al.
(författare)
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Improved Pedestrian Detection under Mutual Interference by FMCW Radar Communications
- 2018
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Ingår i: IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC. - 9781538660096 ; , s. 101-105
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Konferensbidrag (refereegranskat)abstract
- The widespread of automotive radars leads to increase of mutual interference, which in turn degrades road safety. The effect of mutual interference with a focus on detection of pedestrians is investigated. It is shown that detection of pedestrians degrades in the presence of mutual interference. A joint radar communication solution is proposed that increases pedestrian detection probability with negligible impact in the ranging error.
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| 9. |
- Koirala, Remun, et al.
(författare)
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Localization Optimal Multi-user Beamforming with multi-carrier mmWave MIMO
- 2018
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Ingår i: IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC. - 9781538660096 ; 2018-September, s. 1-7
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Konferensbidrag (refereegranskat)abstract
- In this paper, we propose optimal beamforming strategies for a millimeter wave (mmWave) system consisting of multiple users based on the localization performance bounds. We consider a single base station (BS) with prior coarse knowledge of the users' positions and formulate the optimal beamforming problem in order to minimize the localization error consisting of Cramer Rao Lower Bounds (CRLBs) of delay, angle of departure (AoD) and angle of arrival (AoA) estimation at the mobile users. We first formulate the simplified CRLB of estimation parameters, taking advantage of multiple sub-carriers, and then formulate the localization error for optimization of the beamformer. Finally, we evaluate the resulting position and orientation error bounds after optimization for several fairness strategies through Monte Carlo simulations.
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| 10. |
- Kulmer, Josef, et al.
(författare)
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Impact of Rough Surface Scattering on Stochastic Multipath Component Models
- 2018
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Ingår i: IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, PIMRC. - 9781538660096 ; , s. 1410-1416
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Konferensbidrag (refereegranskat)abstract
- Multipath-assisted positioning makes use of specular multipath components (MPCs), whose parameters are geometrically related to the positions of the transceiver nodes. Diffuse scattering from rough surfaces affects the observed specular reflections in the angular and delay domains. Based on the effective roughness approach, the angular delay power spectrum can be calculated as a function of location parameters, which-in a next step-could be useful to accurately characterize the position-related information of MPCs. The calculated power spectra follow reported characteristics of stochastic multipath models, i.e. Gaussian shape in the angular domain and an exponential shape in the delay domain. The resulting angular and delay spreads are in an equivalent range to values reported in literature.
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