Christopher Brunner

Qualcomm

Advances in consumer electronics products and the technology seen in personal computers, digital cameras, and smartphones phones have led to the price/performance ratio of sensors and processors falling dramatically over the last decade. In particular, many consumer products are packaged with small cameras, gyroscopes, and accelerometers, all senso...

We address the state estimation, control and planning for aggressive flight with a 150 cm diameter, 250 gram quadrotor equipped only with a single camera and an Inertial Measurement Unit (IMU). The use of smartphone grade hardware and the small scale provides an inexpensive and practical solution for autonomous flight in indoor environments. The ke...

Vision based tracking of a mobile device is used to remotely control a robot. For example, images captured by a mobile device, e.g., in a video stream, are used for vision based tracking of the pose of the mobile device with respect to the imaged environment. Changes in the pose of the mobile device, i.e., the trajectory of the mobile device, are d...

Methods and apparatus are described herein for calibration and correction of non-constant sensor errors, and in particular non-constant compass errors, that are based in part on changing software and hardware modes of a host device. The non-constant errors induced in the sensor by each mode and combination of modes is determined in a calibration th...

A multi-dimensional sensor, a magnetometer or accelerometer, is calibrated based on the raw data provided by the sensor. Raw data is collected and may be used to generate ellipse or ellipsoid parameters, for a two-dimensional or three-dimensional sensor, respectively. An offset calibration factor is calculated based on the raw data, e.g., the deter...

Activity recognition along with device position recognition can provide contextual cues suitable to infer user interruptibility and device accessibility. Our system fuses data from accelerometer and multiple light sensors to classify activities and device positions. Previously published results achieve robust activity recognition performance with m...

The capacity of linear multiple input multiple output sys-tems strongly depends both on the statistical properties of the channel connecting the output with the input, and the availability of information about system parameters at the input. This paper compares correlated and uncorrelated chan-nels with different degrees of knowlegde about the chan...

In modern cellular systems such as HSPA and LTE, link- and cell level performance has largely been optimized. This is less true for performance on inter-cell level where antenna parameters and new site locations are set based on expensive and limited drive tests and inaccurate propagation models. Since the 3G ecosystem already provides devices for...

IntroductionInter-System Boundary PlanningInter-System Transitions in Connected ModeInter-System Transitions in Idle ModeTest Setup for Inter-System Handover and Cell Reselection Performance AssessmentOptimizing Inter-System ParametersAdditional Inter-System Planning and Optimization IssuesReferences

IntroductionPhysical Layer ParametersIntra-frequency Cell Reselection ParametersAccess Parameter RecommendationsIntra-frequency Handover ParametersReferences

A complete and practical guide to WCDMA/UMTS cellular network deployment. After introducing the network architecture of such a system, the WCDMA (UMTS) Deployment Handbook defines the coverage and capacity concepts associated with the dimensioning and design phases. Progressing to a discussion of the main system parameters associated with network o...

With WCDMA networks being deployed in Europe and throughout the world, one of the big challenges is to make cell reselection and handover between WCDMA and GSM work smoothly. In this paper, we highlight different strategies for inter-system handover, discuss the impact of intra-frequency handover parameters on inter-system handover performance, and...

With WCDMA networks being deployed in Europe and throughout the world, one of the big challenges is to make cell reselection and handover between GSM and WCDMA work smoothly. Inter-system cell reselection between WCDMA and GSM enables the user equipment in idle mode to choose a new cell of another system to camp on, thus providing service availabil...

With UMTS deployments well underway, one of the key performance metrics is standby time. In idle mode, standby time depends on the cell reselection mechanism. Operators can adjust stand-by time and camping cell quality performance by optimizing operator-configurable cell reselection parameters to, for instance, differentiate their service from othe...

In this paper, we examine the performance enhancement that can be achieved by using smart antenna arrays compared to a three-sector antenna configuration at the base station for the reverse !ink of Wideband CDMA (WCDMA) cellular radio systems. The smart antenna array geometry adopted is uniform circular (UCA) and desired signals impinging on differ...

The deployment of adaptive antennas at base stations considerably increases the spectral efficiency of wireless communication systems. To reduce the computational complexity and increase performance of space-time (ST) processing, processing may take place in reduced dimension, i.e., pre-filtering takes place which is related to linear estimation th...

We study the performance of optimal spatial filters in flat fading channels by means of antenna and diversity gains, by which we denote an amplification of mean signal levels and a reduction of fading-related fluctuation, respec- tively. For these gain variables, we introduce mathematical expressions by considering the transformation of short-term...

A tracking solution to the downlink eigenbeamforming in WCDMA is presented. To this end, we propose a distributed implementation of the eigenspace/-beam tracking at the UE and BS, respectively. Moreover, the specific nature of the deployed tracking scheme offers a advantageous feedback signalling. The proposed performance measure is given by the ra...

We investigate the effects of both fading correlations and transmitter channel knowledge in multiple element antenna (MEA) communication systems. While, for independent and identically distributed fades between receive and transmit antennas, pioneering work showed that a huge increase in capacity is possible for MEA compared to a single antenna sys...

For WCDMA base stations using adaptive antennas, we present a new space-time RAKE structure for uplink reception. Our approach combines short-term and long-term spatial and temporal channel properties using an eigenanalysis. By choosing dominant eigenbeams in time and space, the algorithm enhances interference suppression as well as spatial and tem...

Adaptive space-frequency RAKE receivers use diversity combining and multiuser interference suppression to obtain a considerable increase in performance in DS-CDMA systems such as WCDMA. The main advantages of operation in the space-frequency domain include a reduced computational complexity and an improved noise suppression. To this end, the signal...

The detailed knowledge of the directional characteristics of the mobile radio channel is required to develop directional channel models and to design efficient smart antenna concepts for future mobile radio systems. In this paper, we examine the applicability and performance of two popular high-resolution parameter estimation schemes for directiona...

The downlink spectral efficiency of third generation mobile radio systems is especially important since several services will be asymmetric, i.e., on the average the downlink data rates will be higher than on the uplink. We propose to utilize adaptive antennas at the base stations because spatial interference suppression is able to reduce the near-...

Adaptive space-frequency RAKE receivers use maximum ratio combining and multi-user interference suppression to obtain a considerable increase in performance in DS-CDMA systems such as WCDMA. To this end, the signal-plus-interference-and-noise and the interference-plus-noise space-time covariance matrices are estimated. The computational complexity...

Adaptive space-time RAKE receivers use diversity combining and multi-user interference suppression to obtain a considerable increase in performance in DS-CDMA systems such as wideband CDMA (WCDMA). We compare the structure and performance of different space-time RAKE receivers for WCDMA. After a review of the decoupled space-time RAKE and the joint...

The detailed knowledge of the directional characteristics of the mobile radio channel is required to develop directional channel models and to design efficient smart antenna concepts for future mobile radio systems. We present an efficient high-resolution scheme to estimate the dominant wavefronts in terms of their two-dimensional arrival angles (a...

Future wireless communication systems require an increased spectral efficiency to accommodate the growing number of users and permit connections with higher data rates. To this end, smart antenna arrays utilizing adaptive beamforming techniques on the uplink as well as the downlink enable space division multiple access (SDMA). Furthermore, the rang...

In wireless communications, the estimation of the dominant directions of arrival at the base station facilitates the use of advanced mo- bile positioning algorithms, the implementation of beamforming schemes for smart antennas, and the development of directional channel mod- els. In this paper, we present an efficient high-resolution technique to e...

Two data detection schemes for the uplink of a space division multiple access (SDMA) system are compared in this paper. The first scheme separates the dominant wavefronts using a two-dimensional (2-D) spatial filter based on 2-D Unitary ESPRIT. The separated wavefronts are assigned to the users by correlating them with known training sequences. To...

We study the performance of optimum combining in frequency-flat directional fading channels with co-channel interfer- ence (CCI) from the perspective of diversity, beamforming, and interference suppression. Two fundamental performance measures are introduced using input and output signal-to-noise-and interference (SINR) statistics: the mean SINR ga...