| 1. |
- Böhm, Annette, 1975-, et al.
(författare)
-
Data age based MAC scheme for fast and reliable communication within and between platoons of vehicles
- 2016
-
Ingår i: International Conference on Wireless and Mobile Computing, Networking and Communications. - Piscataway : IEEE. - 9781509007240 - 9781509007257
-
Konferensbidrag (refereegranskat)abstract
- Heavy vehicles driving as platoon with highly reduced inter-vehicle gaps has shown considerable fuel saving potential, but put high timing and reliability requirements on the underlying control data exchange. The recently standardized IEEE 802.11p protocol suite for Vehicular Ad-Hoc Networks (VANETs) and its message types do neither support the demands of a platooning application nor take advantage of its properties. We therefore propose a framework for centralized channel access with retransmission capabilities for safety critical control data exchange based on the data age of earlier received messages, DA-RE (Data Age based REtransmission scheme). A simulation comparison to the 802.11p random access Medium Access Control (MAC) protocol shows that the intelligent assignment of retransmission opportunities considerably improves the reliability of platooning control data. We also propose a power control based scheme for early platoon detection allowing several platoons to temporarily share a channel and show that the safe and reliable operation of their vehicles is not compromised. © 2016 IEEE.
|
|
| 2. |
- Karlsson, Alexander, et al.
(författare)
-
Energy-efficient 5G deployment in rural areas
- 2016
-
Ingår i: 12th IEEE International Conference on Wireless and Mobile Computing, Networking and Communications, WiMob 2016. - : IEEE Computer Society. - 9781509007240
-
Konferensbidrag (refereegranskat)abstract
- Energy efficiency is of profound importance for prospective 5G wireless networks, especially in sparsely populated rural areas where broadband mobile services should be provided at a reasonable cost. In this paper the impact of beamforming (BF) and cell discontinuous transmission (cell DTX) technologies on the average area power consumption is studied. The required density of base stations for a 5G cellular system in a rural environment is also investigated. For this purpose, we propose a simple rural area model that captures a non-uniform distribution of users and employ the generalized Lloyd algorithm to determine the deployment of base stations. We assume a 5G system operating in mmWave band centered at 28 GHz with the bandwidth of 100 MHz, compared with existing LTE networks at 0.8 GHz with a 20 MHz bandwidth. Simulation results show that for the 5G network the density of base stations needed to provide 50 Mbps for 95% of users at the busy hour will be reduced by 8-9 times with the implementation of BF. It is also observed that BF has a greater effect on the energy saving of 5G networks in rural areas in comparison to the cell DTX.
|
|
| 3. |
- Rethfeldt, M., et al.
(författare)
-
ViPMesh : A virtual prototyping framework for IEEE 802.11s wireless mesh networks
- 2016
-
Ingår i: International Conference on Wireless and Mobile Computing, Networking and Communications. - : IEEE Computer Society. - 9781509007240
-
Konferensbidrag (refereegranskat)abstract
- WLAN mesh networks are characterized by their flexible and low-cost deployment, scalability, and self-healing capabilities. The new WLAN standard IEEE 802.11s introduces low-level mesh interoperability. However, building large-scale real-world test beds and reproducible setups is challenging and costly. In the majority of research works, network simulation is preferred over practical measurements. Here, the main disadvantage exists in simplified device and protocol models restricting the comparability to practical implementations. In contrast, using device emulation still requires the simulation of wireless channel and environment models. Consequently, a combination of both emulation and simulation is needed to enable virtual prototyping of real applications and protocols in WLAN mesh networks. Nevertheless, the computation of complex wireless channel effects requires a decoupling of wall clock and simulation time. Therefore, we present ViPMesh, a virtual prototyping framework for IEEE 802.11s and its Linux reference implementation. ViPMesh relies on WLAN device emulation and nested virtualization using QEMU and Linux containers to support the analysis of real applications on top of an unmodified protocol stack. Adopting an alternative time source approach for QEMU, ViPMesh acts as discrete-event simulator. It further integrates channel and environment models with support for IEEE 802.11n MIMO techniques, high throughput modes, multi-channel operation, and node mobility. To the best of our knowledge, this is the first approach that combines the IEEE 802.11s reference implementation with the described simulation features. The functionality of ViPMesh is demonstrated in different example scenarios.
|
|
| 4. |
- Zhang, L., et al.
(författare)
-
Centralized caching in two-layer networks : Algorithms and limits
- 2016
-
Ingår i: International Conference on Wireless and Mobile Computing, Networking and Communications. - : IEEE Computer Society. - 9781509007240
-
Konferensbidrag (refereegranskat)abstract
- The problem of the centralized caching is studied in a two-layer network. The first layer of the network is constructed by a server and K1 helpers, and the second layer consists of K1 orthogonal sub-networks, each of which contains a helper and K2 users. The pioneer caching design in the two-layer network is to directly apply the Maddah-Ali & Niesen (MAU) centralized caching [1] into individual layers, such that single-layer multicast opportunities (SMO) are deployed. In this paper, a joint caching (JC) algorithm is developed by exploiting both the SMO and the correlations of caching contents across two layers, namely, cross-layer storage correlations (CSC). Furthermore, cross-layer multicast opportunities (CMO) can also be created by applying the MAU scheme between the server and users. In order to simultaneously obtain the caching gains from SMO, CSC, and CMO, a hybrid caching scheme is proposed and demonstrated to be order-optimal when the storage sizes at both helpers and users are limited. In other words, the achievable rate region lies within a constant multiplicative and additive gap of the information-theoretic bounds. In particular, the multiplicative and additive factors can be carefully characterized to be 1/48 and 4, respectively.
|
|
