Michael Färber

Future Mobile Communication Networks: Challenges in the Design and Operation

This article highlights particular challenges inherent in the design and operation of future mobile communications systems This paper also discusses the various degrees of freedom involved, and points out which design paradigms appear most promising and which major fields of future research remain.

Densification in mobile networks and the potential evolution paths of the base station

The base station (BS) is the element of a mobile network that connects a number of user equipments (UEs) from various vendors to a mobile network via a wireless interface. The network behind the base station was consistently a subject of many evolutionary steps. In recent system concepts like LTE and LTE-Advanced the network architecture had been required to be flat. Densification of the networks by a small cell underlay network, by picos, relays and femto may change the role of the macro base station. Depending on the evolution of small cell deployments, the function split between these nodes can imply functional enhancements like a control function for subnetworks. The paper discusses the potential implications and the possible architecture evolution with a base stations acting as a new central control element for various kind of sub-networks.

Pass It on: Advanced Relaying Concepts and Challenges for Networks Beyond 4G

Relay nodes (RNs) will be a key feature of future wireless networks. RNs can extend coverage, increase network capacity, and provide more uniform quality-of-service (QoS) across the cell area in a cost-effective manner. Therefore, not surprisingly, relaying techniques have attracted a significant amount of attention from the wireless industry and standards. The Third-Generation Partnership Project (3GPP) release 10 has considered RNs that act as base stations (BSs), known as type-1 RNs, aiming only for coverage extension. However, RNs can be employed in different ways, and several challenges have to be addressed to attain the theoretical gains. This article presents an overview of the relaying concepts related to the 3GPP long-term evolution (LTE) road map, i.e., concepts related to type-1, type-2, and moving RNs. The implementation challenges are outlined, and a number of promising solutions for each RN type are discussed. More specifically, for type-1 RNs, this article focuses on the allocation of resources to the backhaul and access links. For type-2 RNs, the focus is on designing distributed hybrid automatic repeat request (HARQ) protocols that involve RNs. Moving RNs are presented as an efficient solution to the ever-growing demand for wireless broadband by vehicleborne users. Overall, the presented relaying concepts and solutions can significantly improve the user experience and can play an important role in the future.