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This paper presents a novel memory optimization technique to exploit the analogy between correlation coefficients in MMSE-based channel estimators across multiple standards. The need for coefficient storage for robust MMSE channel estimators is expensive in terms of on-chip memory. Besides, the memory requirements grow linearly by integrating more standards onto one platform. Thus, it becomes inev

This study describes a high throughput constant envelope (CE) pre-coder for Massive MIMO systems. A large number of antennas (M), in the order of 100s, serve a relatively small number of users (K) simultaneously. The stringent amplitude constraint (only phase changes) in the CE scheme is motivated by the use of highly power-efficient non-linear RF power amplifiers. We propose a scheme that compute

In large software organizations with a product line development approach, system test planning and scope selection is a complex tasks for which tool support is needed. Due to repeated testing: across different testing levels, over time (test for regression) as well as of different variants, the risk of double testing is large as well as the risk of overlooking important tests, hidden by the huge a

Wireless communication using very-large multiple-input multiple-output (MIMO) antennas is a new research field, where base stations are equipped with a very large number of antennas as compared to previously considered systems. Unlike the conventional small and compact antenna arrays, the very-large arrays may span many wavelengths in space, thus they can experience large-scale fading over the arr

This paper presents a directional analysis of the on-body propagation channels using the high resolution space alternating generalized expectation (SAGE) maximization algorithm. The analysis has been done on data obtained through FDTD simulations, on a male and a female numerical phantom. For estimating the angle of arrival (AoA) at a four element square array located at the chest, two different p

We introduce the problem of reoptimizing the network after a link failure has been repaired as an effective way for reducing capacity usage and improving network performance. Numerical results show gains higher than 42%.

Max-min fairness (MMF) is a general objective of multi-criteria optimization with important and natural applications in communication network design. The notion of MMF and optimization models involving MMF seem not to be commonly known to network designers and therefore they are not used to an extent they deserve. Moreover, the MMF approaches are sometimes “reinvented”, in some cases not correctly

A new version of the stream cipher Grain-128 is proposed. The new version, Grain-128a, is strengthened against all known attacks and observations on the original Grain-128, and has built-in support for authentication. The changes are modest, keeping the basic structure of Grain-128. This gives a high confidence in Grain-128a and allows for easy updating of existing implementations.

In this paper we consider time-division-duplex (TDD) reciprocity calibration of a massive MIMO system. The calibration of a massive MIMO system can be done entirely at the base station (BS) side by sounding the BS antennas one-by-one while receiving with the other BS antennas. With an M antenna BS, this generates M(M - 1) signals that can be used for calibration purposes. In this paper we study se

Primary and backup paths in MPLS fast reroute (FRR) may be established as shortest paths according to the administrative link costs of the IP control plane, or as explicitly calculated arbitrary paths. In both cases, the path layout can be optimized so that the maximum link utilization for a set of considered failure scenarios is minimized. In this paper, we propose a linear program for the optimi

Successful projects require two key elements to be set: the time frame for the project and the scope of the project. Accurately deciding these two attributes greatly increases the probability of success. If, for example we would like to build a house, we should start building it in spring so that we can lie the foundations of the house on a non-frozen ground. Moreover, we know that we should be re

Multipath routing of traffic demands, known also as bifurcated routing or load sharing, has been studied for various telecommunication networks for a long time. An advantage of multipath routing is that it gives a demand the opportunity to use multiple paths through the network to send its traffic. In a single-commodity situation, this benefit can be clearly seen. When multiple demands (multi-comm