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Interference between femto-cell systems is a critical factor for the deployment of such systems in, e.g., resedential areas. In this paper we report on a residential channel measurement campaign focusing on the channel properties for femtocell systems. We characterize basic channel properties such as delay spread and interference levels between different furnished residential houses. In addition w
The current family of 802.11 protocols are based on the Carrier Sense Multiple Access (CSMA) mechanism which is a simple and robust means of sharing a channel. However, two current trends in wireless networks point towards a situation where CSMA fails to perform better than pure random access solutions such as ALOHA. The first trend is the ever increasing raw data rate in each generation of 802.11
One of the latest additions in defining the test process is the upcoming ISO/IEC 29119 standard, which aims to define a universally applicable generic test process model. However, currently the standard does not offer any support for the adoption process of the model. In this paper, we present our framework, which aims to combine a maturity level-based approach with the standard process. Our objec
Analytical Multiple-Input Multiple-Output (MIMO) models are often attractive due to their low complexity when analyzing possibilities and limitations in the system. In this paper we outline a a possible dual link extension of an analytical MIMO channel model and investigate its suitability based on measurements of a dual link MIMO scenario. The extension is based on the correlation matrix distance
In secure computing systems, isolation between different components is normally the basis for security. However, ab- solute isolation is seldom desired nor practical. Often for the system to function, a secure communication channel between otherwise isolated components is also needed. In this work, we consider implementation of the secure Remote Procedure Call (RPC) mechanism defined by the Global
The development of MIMO over-the-air (OTA) test methodology is an ongoing activity in 3GPP RAN4, CTIA and EU COST Action 2100. In this paper, the focus is on the anechoic chamber approach, which uses a uniform circular array of probe antennas to replicate directional channels for the device under test (DUT) at the array center. In particular, we study in simulation the complexity requirements of i
We consider a class of weak feedback polynomials for LFSRs in the nonlinear combiner. When feedback taps are located in small groups, a distinguishing attack can sometimes be improved considerably, compared to the common attack that uses low weight multiples. This class of weak polynomials was introduced in 2004 and the main property of the attack is that the noise variables are represented as vec
Shadowing from vehicles can degrade the performance of vehicle-to-vehicle (V2V) communication systems significantly. It is thus important to characterize and model the influence of common shadowing objects like cars properly. For multilink systems it is essential to model the joint effects on the different links. However, the multilink shadowing effects in V2V channels are not yet well understood.
This paper presents an architecture of an auto-correlator for Orthogonal Frequency Division Multiplexing systems. The received signal is quantized to only the sign-bit, which dramatically simplifies the frequency offset estimation. Hardware cost is reduced under the assumption that synchronization during acquisition does not have to be very accurate, but sufficient for coarse estimation. The archi
Attribute grammars are useful in integrated editing environments for obtaining automatic incremental compilation features. However, traditional attribute grammars use aggregated values during name resolution, resulting in large sets of affected attribute instances after edits. In this paper, we show how reference attribute grammars (RAGs) can significantly reduce the number of affected attributes.
The friction stir welding procedure to seal copper canisters requires variable power input throughout the 45 minute long weld cycle to keep the welding temperature within the process window. This is due to variable thermal boundary conditions throughout the weld cycle which, together with fast disturbances in the spindle torque, requires control of both the power input and the welding temperature
As our society becomes more and more dependent on IT systems, failures of these systems can harm more and more people and organizations both public and private. Diligently performing risk and hazard analysis helps to minimize the societal harms of IT system failures. In this paper we present experiences gained by applying the System Theoretic Process Analysis (STPA) method for hazard analysis on a
This paper presents low power hardware generation, based on a CAL actor language dataflow implementation. The CAL language gives a higher level of abstraction and generate both hardware and software description. The original CAL flow is targeted for hardware-software co-design of complex systems on FPGA. Modifications are done to the original CAL flow to facilitate low power ASIC implementations.
Antenna systems are provided including a chassi (115) and first and second radiating (110, 120) elements coupled to the chassi. The first radiating element is configured to amplify excitation of the chassi and the second radiating element is configured to reduce excitation of the chassi so as to reduce mutual coupling in the antenna system. Related co- located antennas and methods of controlling m
In this paper, we present a thin single-arm Archimedean spiral antenna designed to be used in underground soil measurements to characterize the dielectric properties of soil during freezing and thawing processes. The designed antenna works in low permittivity, low-loss frozen soil as well as in high permittivity, high-loss marshy soil and operates over the frequency range 1–3 GHz. The antennas has
