UTRA/FDD RF Transceiver Requirements

Unified RF requirements are derived for an UMTS Terrestrial RadioAccess/Frequency Division Duplex (UTRA/FDD) compliant mobile transceiver. Aset of transceiver requirements are proposed with consideration to systemissues including duplex aspects. From these design-compatible requirements areproposed for each functional block in the transceiver.     

CO2 Capture technologies: Current status and new directions using supported ionic liquid phase (SILP) absorbers

Current state-of-the-art techniques for CO2 capture are presented and discussed. Post-combustion capture of CO2 by absorption is the technology most easily retrofitted to existing installations, but at present this is not economically viable to install and run. Using ionic liquids instead of aqueous amine solutions overcomes the major thermodynamic issues. By applying SILP technology further advances, in terms of ease of handling and sorption dynamics, are obtained. Initial experimental studies showed that ionic liquids such as tetrahexylammonium prolinate, [N6666][Pro], provide a good candidate for CO2 absorption using SILP technology. Thus a solid SILP absorber comprised of 40 wt% [N6666][Pro] loaded on precalcined silica quantitatively takes up about 1.2 mole CO2 per mole of ionic liquid in consecutive absorption-desorption cycles in a flow-experiment performed with 0.09 bar of CO2 (9% CO2 in He).     

A four-step method for de-embedding gigahertz on-wafer CMOSmeasurements

In this paper, a de-embedding method is proposed for conducting accurate on-wafer device measurements in the gigahertz range. The method addresses issues of substrate coupling and contact effects and is therefore suitable for measurements with lossy technologies such as CMOS. The method assumes a probe-tip two-port calibration performed with well-known techniques and impedance substrates. By employing a physical interpretation of the test-fixture, the method alleviates a number of known problems with common de-embedding procedures. Four distinct mathematical steps are suggested to de-embed parasitics for the test-fixture to give an accurate measurement of the device under test. By introducing a simple compensation factor for in-fixture standard imperfections, the proposed method allows large devices to be measured with high accuracy. The applicability of the method is demonstrated with measurements up to 12 GHz     

Effects of Dominant Other-Sector Interference on Dual Rx-Antenna HSDPA Performance

Link level SINR simulation results and network level sector throughput simulation results that quantify the benefit of dual antenna MMSE reception in a macrocellular WCDMA/HSDPA system are provided. Dual antenna RAKE receiver performance serves as baseline reference. Link-level simulation results are accompanied by a novel analytical expression that in flat Rayleigh fading and for uncorrelated rx-antenna branches describes spatial interference suppression mean SINR gain as function of a dominant other-sector interference ratio (DIR). It is shown that the MMSE receiver’s spatial interference suppression gain heavily depends on the amount of experienced DIR. The higher the DIR the higher the SINR gain. Nevertheless, seen on network level the SINR gain turns into moderate sector throughput gain, well below 50%. This is due to the fact that high DIR situations are rare in the investigated macrocellular scenario. Moreover, the logarithmic relation between SINR and capacity hinders translation of the full SINR gain into HSDPA sector throughput.     

An overview of downlink radio resource management for UTRAN long-term evolution [Accepted from Open Call]

Radio resource management algorithms ranging from bearer admission control to semi-persistent and dynamic packet scheduling, fast link adaptation, and transmission control of multiantenna transmission modes are addressed in this article for UTRAN long-term evolution. First, a high-level system overview of LTE is given, with special emphasis on the important components related to RRM. The quality of service parameter framework is outlined, as one of the main objectives for the families of RRM algorithms is to maximize system capacity while serving all users according to their minimum QoS constraints. It is demonstrated how the collocation of the RRM algorithms at the base station with easy access to air interface measurements offers opportunities for efficient cross-functional optimization between layers 1, 2, and 3. Examples of performance results for different traffic mixes and antenna transmission schemes are also presented, and the article is concluded with recommendations on how to operate the various RRM options under different load and traffic conditions.     

Implementation aspects for successive interference cancellation in DS/CDMA systems

This paper addresses the practical implementation of Successive Interference Cancellation (SIC) for DS/CDMA systems. The practical aspects of such an implementation are discussed and a convenient pipelined architecture is presented. An important aspect is the integration of power control (PC) and interference cancellation which has synergistic effects of optimizing the SIC, reducing intercell interference, and facilitating the implementation. This revised version was published online in July 2006 with corrections to the Cover Date.     

EM-Simulation of Planar Inductor Performance for Epitaxial Silicon Processes

We used a 2.5D EM-simulator to study planar inductor performance in a submicron CMOS technology. We found good agreement between simulations and measurements using only the nominal process parameters for the layer thicknesses, permittivities, and conductivities. By sweeping the thickness and conductivity of the epitaxial layer we show how these parameters affect inductor performance. The presence of a highly conductive substrate layer is shown to have a detrimental effect on inductor performance whereas the thickness and conductivity of the epitaxial layer is less important.