µ-MaxWeight queueing network control with application to in-flight entertainment systems

Although having a multitude of practical applications, the control of large queueing networks is a notoriously difficult problem. It becomes especially challenging when, besides guaranteeing stability, a given cost metric shall be minimized. Recently, an interesting new policy design framework for the control problem, called h-MaxWeight, has been proposed which is a natural generalization of the famous MaxWeight policy. Stability of the policy is achieved through a perturbation technique, however, the stability crucially depends on the choice of parameters which has to be adapted in simulations. In this paper we use a different perturbation technique where the required properties are much easier to implement. This leads to a novel control framework, called µ-MaxWeight, which guarantees universal stability while still operating 'close' to the underlying cost criterion. To illustrate the approach we focus on the example of an in-flight entertainment system which has both wired and wireless components as well as queueing constraints, including buffer underflow constraints. We determine a suitable cost function for this scenario and perform simulations, which suggest that the new approach to policy synthesis can provide significantly higher gains irrespective of any further assumptions on the network model or parameter choice

Wireless network design under service constraints

In this paper we consider the design of wireless queueing network control policies with special focus on application-dependent service constraints. In particular we consider streaming traffic induced requirements such as avoiding buffer underflows, which significantly complicate the control problem compared to guaranteeing throughput optimality only. Since state-of-the-art approaches for enforcing minimum buffer constraints in broadcast networks are not suitable for application in general networks we argue for a cost function based approach, which combines throughput optimality with flexibility regarding service constraints. New theoretical stability results are presented and various candidate cost functions are investigated concerning their suitability for use in wireless networks with streaming media traffic. Furthermore we show how the cost function based approach can be used to aid wireless network design with respect to important system parameters. The performance is demonstrated using numerical simulations

Energy-efficient node selection for cooperative spectrum sensing with spatial correlation

In this paper we investigate the node placement for a wireless sensor network deployed to sense the spectrum with spatial channel correlation. The goal is to find the best node constellation, such that the given power constraints are satisfied and the best sensing performance is acquired. We derive the analytical expression for probability of detection (PD) of the optimal test statistic as the measure of performance. Then we develop two heuristic methods to solve the non-convex optimization problem. Using numerical simulations the analytical expressions for PD is justified, as well as, the performance of the two proposed suboptimal approaches

Interference identification in cellular networks via adaptive projected subgradient methods

We develop an adaptive algorithm to estimate a channel gain matrix in cellular heterogeneous networks. This algorithm has the objective of providing important information to interference coordination and management schemes, a crucial functionality of 'beyond 2020 networks'. In more detail, we pose the estimation problem as a set-theoretic adaptive filtering problem. In the proposed scheme, the channel gain matrix is tracked with the adaptive projected subgradient method (APSM), a powerful iterative tool that can seamlessly use prior information and information gained by measurements. More precisely, we construct multiple closed convex sets, each of which containing estimates that are consistent with a piece of information about the channel gain matrix. The intersection of these sets corresponds to estimates that are consistent with all available information. In particular, we use the following information to construct the sets: i) physical upper and lower bounds of the path gains, ii) interference bounds for the downlink and uplink communication, and iii) received signal received power (RSRP) measurements. The algorithm produces a sequence of estimates where each term is an estimate that approaches the intersection of the multiple sets available at a given time instant. Simulations show that the proposed algorithm is able to track the channel gain matrix in scenarios with mobile users, and it outperforms standard adaptive filters that do not use prior information

Bi-orthogonal waveforms for 5G random access with short message support

One of the main drivers for new waveforms in future 5G wireless communication systems is to handle efficiently the variety of traffic types and requirements. In this paper, we introduce a new random access within the standard acquisition procedures to support sporadic traffic as an enabler of the Internet of Things (IoT). The major challenge hereby is to cope with the highly asynchronous access of different devices and to allow transmission of control signaling and payload "in one shot". We address this challenge by using a waveform design approach based on bi-orthogonal frequency division multiplexing. We show that this approach allows data transmission in frequencies that otherwise have to remain unused. More precisely, we utilize frequencies previously used as guard bands, located towards the standard synchronous communication pipes as well as in between the typically small amount of resources used by each IoT device. We demonstrate the superiority of this waveform approach over the conventional random access using numerical experiments

AODR: A Novel Retransmission Scheme for WIA-FA Networks

In industrial wireless sensor networks (IWSNs), monitoring data generated by field devices are supposed to be delivered to the gateway with low latency and high reliability. However, most of industrial wireless standards are based on IEEE 802.15.4 and offer limited data rates, which prevents their adoption in critical scenarios. Based on IEEE 802.11, WIA-FA is proposed to address higher communication requirements in factory automation. In this paper, we first analyze the drawbacks of the default NACK-based retransmission scheme of WIA-FA, and then propose an automatic on-demand retransmission (AODR) scheme. Finally, we give a detailed reliability analysis of the proposed AODR scheme. Simulation results show that the proposed AODR scheme outperforms existing works in terms of reliability for different scenarios

Mobile health in cardiology: a review of currently available medical apps and equipment for remote monitoring

Cardiolog

5GNOW: Intermediate frame structure and transceiver concepts

This paper reports intermediate transceiver and frame structure concepts and corresponding results from the European FP7 research project 5GNOW. The core is the unified frame structure concept which supports an integrated 5G air interface, capable of dealing both with broadband data services and small packet services within the same band. It is essential for this concept to introduce waveforms which are more robust than OFDM, e.g., with respect to time-frequency misalignment. Encouraging candidate waveform technologies are presented and discussed with respective results. This goes along with the corresponding multiple access technologies using multi-layered signals and advanced multi-user receivers. In addition we introduce new (compressive) random access strategies to enable 'one shot transmission' with greatly reduced control signaling particularly for sporadic traffic by orders of magnitude. Finally, we comment on the recent results on the 5GNOW networking interface. The intermediate results of 5GNOW lay the ground for the standardization path towards a new 5G air interface beyond LTE-A