Distributed Channel Assignment in Cognitive Radio Networks: Stable Matching and Walrasian Equilibrium

We consider a set of secondary transmitter-receiver pairs in a cognitive radio setting. Based on channel sensing and access performances, we consider the problem of assigning channels orthogonally to secondary users through distributed coordination and cooperation algorithms. Two economic models are applied for this purpose: matching markets and competitive markets. In the matching market model, secondary users and channels build two agent sets. We implement a stable matching algorithm in which each secondary user, based on his achievable rate, proposes to the coordinator to be matched with desirable channels. The coordinator accepts or rejects the proposals based on the channel preferences which depend on interference from the secondary user. The coordination algorithm is of low complexity and can adapt to network dynamics. In the competitive market model, channels are associated with prices and secondary users are endowed with monetary budget. Each secondary user, based on his utility function and current channel prices, demands a set of channels. A Walrasian equilibrium maximizes the sum utility and equates the channel demand to their supply. We prove the existence of Walrasian equilibrium and propose a cooperative mechanism to reach it. The performance and complexity of the proposed solutions are illustrated by numerical simulations.Comment: submitted to IEEE Transactions on Wireless Communicaitons, 13 pages, 10 figures, 4 table

Power and Beam Optimization for Uplink Millimeter-Wave Hotspot Communication Systems

We propose an effective interference management and beamforming mechanism for uplink communication systems that yields fair allocation of rates. In particular, we consider a hotspot area of a millimeter-wave (mmWave) access network consisting of multiple user equipment (UE) in the uplink and multiple access points (APs) with directional antennas and adjustable beam widths and directions (beam configurations). This network suffers tremendously from multi-beam multi-user interference, and, to improve the uplink transmission performance, we propose a centralized scheme that optimizes the power, the beam width, the beam direction of the APs, and the UE - AP assignments. This problem involves both continuous and discrete variables, and it has the following structure. If we fix all discrete variables, except for those related to the UE-AP assignment, the resulting optimization problem can be solved optimally. This property enables us to propose a heuristic based on simulated annealing (SA) to address the intractable joint optimization problem with all discrete variables. In more detail, for a fixed configuration of beams, we formulate a weighted rate allocation problem where each user gets the same portion of its maximum achievable rate that it would have under non-interfered conditions. We solve this problem with an iterative fixed point algorithm that optimizes the power of UEs and the UE - AP assignment in the uplink. This fixed point algorithm is combined with SA to improve the beam configurations. Theoretical and numerical results show that the proposed method improves both the UE rates in the lower percentiles and the overall fairness in the network

Software-defined networking in an industrial multi-radio access technology environment

The trend towards Industry 4.0 considers a wide range of new use cases in the context of the factory of the future. These new industrial applications range from augmented workspace applications which require high bandwidth wireless links to deliver information in nearly real-time to others which require seamless mobility and continuous connectivity for wirelessly connected automated guided vehicles (AGVs) to permanently communicate with a back end system. Several scenarios in the context of the factory of the future require ultra-fast and reliable wireless transmission together with real- time processing, e.g., analysis of video data in an Edge Cloud to minimize the delay. Accordingly, wireless connectivity is paving its way into the factories of the future to enable these new applications. Moreover, the concept of Software-Defined Networking (SDN), with the split of the control and data plane, seems a natural fit to programmatically orchestrate networks and slices in the factories of the future, with its vast range of requirements set by the aforementioned use cases

From Radio Design to System Evaluations for Ultra-Reliable and Low-Latency Communication

Ultra-reliable and low-latency communication is the enabler for many new use cases, including wireless industrial automation. Fulfilling varying requirements of these use cases demands a flexible radio design. To address this, a holistic approach needs to be adopted. Therefore, this paper presents the radio access concepts affecting the communication reliability and latency, and comprehensively evaluates link and system level considerations through simulations. In particular, we describe the choice of suitable modulation and coding schemes, and discuss the impact of different numerologies and waveform candidates. We also point out the key principles for radio frame design to reduce the end-to-end latency. The presented concepts are then used to evaluate the performance at system level for an industrial scenario. It is shown that by an appropriate design of the radio interface for 5G system, the required low-latency and high reliability for industrial applications and many other use cases can be achieved.QC 20170919</p

Cellular communication network using a user equipment identifier

The present invention concerns a cellular communication network (10) comprising a base station (11) serving a radio cell (12) and at least one user equipment (13) located within said radio cell (12), wherein the base station (11) is configured to receive a radio signal (14) from the user equipment (13) and to determine at least one signal property (15) of said received radio signal (14), wherein the base station (11) is further configured to assign a user equipment identifier (16) to said user equipment (13) based on the a least one determined signal property (15). The present invention further concerns a base station (11) to be used in the above mentioned cellular network (10) as well as corresponding methods