Dragan Samardzija

Nokia Bell Labs · Wireless

An intelligent wireless sensor network that is designed to save road lighting energy, while maintaining traffic safety, is presented. It consists of an array of nodes that may be installed on both sides of the road, being mutually separated by a few tens to a few hundreds of meters. Each node consists of (i) vehicle detection subsystem, (ii) wirele...

In this paper we propose a novel image interpolation algorithm which preserves edges and keeps a natural texture of interpolated images. The algorithm is based on an idea that only pixels that belong to the same side of an edge should be used in interpolation of pixels that belong to an edge. Beside similarity-based separation of known interpolatio...

The aim of this paper is to provide software for educational purposes in the field of digital signal processing. This paper presents the implementation of the programming environment for graphical analysis of the audio signal. The environment is verified at E2LP platform and as part of the laboratory exercises.

The modern multimedia devices require ever increasing processing power, which is to some extent limited, and to optimize the code to execute in real-time. This paper describes the optimization methods for VP8 decoder for processing video signals based on the MIPS32 architecture. Finally, the execution time was measured for the decoder with data set...

In this paper we propose a novel concept for the street lighting automation, with the primary goal to decrease the level of light pollution and the electric energy waste. The concept enables the street lights, equipped for wireless communica-tion, to be automatically switched on or off according to a presence of humans or moving vehicles. As oppose...

This paper illustrates a device used for set-top box testings. The primary idea was to create a system which can be used for field work. It would be a part of a bigger system which could test both, input and output functions of end users devices. Its modularity and low-power consumption are one of key benefits of this device. Further improvements o...

This paper examines the educational aspect of one way of improving the performance of laboratory exercises in the framework of university courses in the area of standards and technologies of wireless communication systems through a platform for learning. The effects of improvement were measured using student assessment of teaching and survey result...

The Centralized, Cooperative, Cloud Radio Access Network (C-RAN) is a next-generation wireless access network architecture based on centralized processing, collaborative radio, and real time cloud infrastructure. In this architecture, different access technologies (Global System for Mobile Communications (GSM)/Time Division Synchronous Code Divisio...

This paper describes a system of interlinked vehicles used to share information of interest for all traffic participants and the parties responsible for maintaining the infrastructure. Furthermore it presents problems encountered with mobile device GPS inaccuracy, data organisation and search algorithms.

We propose WhiteCell - a dual technology femto cell architecture for wide-area wireless users that addresses some of the critical challenges being faced by the cellular industry today in better meeting surging demands. WhiteCell extends the traditional notion of a femto cell in which small, low-power, short-range access points are placed in homes t...

In current wireless base station solutions it is becoming common to physically separate baseband units and radio subsystems. In many wireless technologies this architecture requires allocation of significant transport network resources. In this paper a low-latency baseband signal compression scheme is presented. The compression scheme significantly...

Efficient wireless sensor nodes have significantly motivated the usage of wireless sensor networks for intrusion detection and surveillance. A passive wireless surveillance network has the ability to detect humans by analyzing only the variations of the signal strength with respect to distance and alignment between nodes. When a human passes throug...

The paper presents a novel method for human detection that is applied to the automatic control of home appliances' power consumption. The method uses a wireless smart outlets network and changes of received signal strength indicator (RSSI) between stationary communication nodes (2.4 GHz smart outlets). The main idea is to monitor the changes of RSS...

C-RAN is the next-generation clean wireless access network architecture, which is based on centralized processing, the Collaborative Radio and Real-time Cloud Infrastructure. In C-RAN architecture, different access technology (eg.GSM / TD-SCDMA / WCDMA / LTE) can be support on the same hardware platform in baseband pool system; C-RAN can be applied...

BLAST[1] has been shown to provide high capacity wireless communications by using multiple antennas at both transmitter and receiver. We have built a narrowband wireless BLAST testbed with multiple transmit and receive antennas. In this paper, we examine the performance of the VBLAST [2, 3] by choosing the antenna configurations and performing link...

ABSTRACT OF THE DISSERTATION Multiple Antenna Wireless Systems and Channel State

Driving in low visibility conditions (night time, fog or heavy precipitation) is particularly challenging task with an increased probability of traffic accidents and possible injuries. Road Nail is a solar powered intelligent road marking system of wirelessly networked signaling devices that improve driver safety in low visibility conditions along...

Radio irregularity phenomenon is often considered as a shortcoming of wireless networks. In this paper we present the method of using radio irregularity as an efficient human presence detection sensor which increases user awareness in smart homes. The idea is based on monitoring the received signal strength indicator (RSSI) between stationary wirel...

This paper presents a solution that exploits changes in radio signal strength (RSSI) to detect a movement or presence of a person within a particular environment. The performance of the proposed scheme is experimentally evaluated. Based on the results, we belive that the proposed scheme is particularly suitable for application in the future intelli...

This paper presents a simulation of positioning various types of transmitters in an optimal way, regarding the positions of receivers and their demands. The simulation runs in regards to the input parameters, which represent a landscape map, positions and demanded bandwidths of receivers, positions and dimensions of forbidden zones and barriers, as...

This paper presents a simulation of positioning various types of transmitters in an optimal way, regarding the positions of receivers and their demands. The simulation runs in regards to input parameters, which represent a landscape map, positions and demanded bandwidths of receivers, positions and dimensions of forbidden zones and barriers, as wel...

In this paper we study the performance of coherent joint-processing coordinated multi-point (CoMP) transmission, also known as Network MIMO, in pico-cellular street de- ployments with lamp-post base station installation. Previously published and experimentally confirmed short-range wireless propagation models have been applied. The performance is c...

In this paper we present Road Nail, an intelligent road marking system with the wireless network of signaling devices that are mounted near the road edge. “Nails” or signaling devices are autonomous nodes with capability to accumulate electrical energy into battery which is obtained from solar panels. In addition, the nodes exchange wireless messag...

In this paper we present Road Nail, an intelligent road marking system with the wireless network of signaling devices that are mounted near the road edge. “Nails” or signaling devices are autonomous nodes with capability to accumulate electrical energy into battery which is obtained from solar panels. In addition, the nodes exchange wireless messag...

We study the impact of higher-order sectorization (up to 12 sectors per cell site) in cellular networks with low angle spread and a high density of users. Under ideal sector patterns (with no intersector interference), the mean throughput per site scales directly with S, the number of sectors per site. Fixing the number of antennas per site to be 1...

In this study we analyze performance of linear single user multiple-input multiple-output (SU-MIMO) detector applied in 3GPP LTE wireless systems. We consider minimum mean square error (MMSE) linear detectors based on (i) explicit matrix inversion, and (ii) adaptive gradient algorithm. We present the average achievable data rates as a function of d...

In this study we analyze the synergy effects among ARQ and Hybrid ARQ with rate-adaptive mechanisms. We present several coding and decoding schemes and link adaptation techniques for rate-adaptive transmission, designed to combat noise, and we discuss their performance. We describe approaches for searching and selecting the best modulation and codi...

The Digital Sound Projector technology provides surround sound with only one speaker, by producing beams of sound. In this paper, we propose an embedded system for joint DTV and Digital Sound Projector, which consists of separate DTV real-time processing and Digital Sound Projector functionality. The verification is done by PC application, by which...

Streaming high quality audio/video (AV) from home media sources to TV sets and audio speakers over a wireless local area network (WLAN) is a challenging problem because of the fluctuating bandwidth caused by interference and fading. Retransmission and data buffering, as common techniques in data transfer over error-prone channels, are not adequate...

Streaming high quality audio/video (AV) from home media sources to TV sets and audio speakers over a wireless local area network (WLAN) is a challenging problem because of the fluctuating bandwidth caused by interference and fading. Retransmission and buffers as common techniques in data transfer over error prone channel are not adequate for delay...

In this paper we present a software model for the embedded systems, that separates functionality (core) from presentation (user interface). The model provides means to easily swap user interfaces, as well as their remote execution. We propose standards, protocols and guidelines for creating portable and scalable embedded software.

In systems employing coordinated base station transmission and reception (also known as network MIMO), information needs to be shared among clusters of coordinated bases. This information includes coherent channel state information, user data, and baseband received signals. The cost of leasing and maintaining a reliable backhaul to share this infor...

In this paper we study the effects of practical pilot- assisted channel state estimation on the achievable information theoretic data rates (uplink and downlink) in a multiple antenna multiuser TDD system. Specifically, we consider a wireless system with multiple antennas at the base station and a number of mobile terminals each with a single anten...

The wireless communication channel between vehicular nodes in an ad-hoc network was assessed in a comprehensive measurement and modeling effort. Nodes were equipped with roof mounted azimuthally omnidirectional antennas, and measurements were taken at both short (line-of-sight) and long ranges, at a center frequency of 2.5 GHz. The median MIMO capa...

In this paper we present a multiuser MIMO experimental system and the corresponding indoor measurement results that demonstrate power of distributed and coherently-coordinated downlink transmit antennas using zero-forcing (ZF) beamforming. We present experimental performance under different conditions and communication scenarios. We consider differ...

Continuous wave Doppler radar systems have been used for non-contact detection of human cardiopulmonary activity, and these functions can be used in diverse applications including health care, emergency, military, or security. For reliable and robust sensing, several schemes are applied to overcome deleterious system sensitivity associated with the...

In this paper we present a wireless multiple antenna experimental system that is used for remote sensing of physiological motion. We introduce a novel detection algorithm that exploits multiple antennas. The algorithm is based on the analysis of the received signal power spectrum, where a unique cost is assigned to each spectral component. The assi...

In this paper we develop a framework for operator competition based on short term ownership of spectrum resources and devise a dynamic spectrum access method called "Dynamic Property Rights Spectrum Access (D-Pass)". In the D-Pass model, spectrum portions are allocated to operators on a short term basis (few sessions) by a SPS (Spectrum Policy Serv...

In this paper we present some analogies between thermodynamics and certain Shannon theory results. We revisit the previously published results that relate notion of energy and information. We then introduce a thermodynamic system that could be used to store information. The ideal gas is considered. We present the corresponding thermodynamic analysi...

We propose a channel state information (CSI) feedback scheme based on unquantized and uncoded (UQ-UC) transmission. We consider a system where a mobile terminal obtains the downlink CSI and feeds it back to the base station using an uplink feedback channel. If the downlink channel is an independent Rayleigh fading channel, then the CSI may be viewe...

To demonstrate a real-time, mobile, peer-to-peer, ad-hoc networked MIMO system in a realistic tactical environment, the Defense Advanced Research Projects Agency (DARPA) has instituted a program, called Mobile Network MIMO (MNM). To assess the communication channel quality for ground level MIMO nodes, a comprehensive channel measurement and modelin...

In this paper we study a multiple antenna multiuser TDD system that uses pilot assisted channel state estimation. Specifically, we consider a wireless system with multiple antennas at the base station and a number of mobile terminals each with a single antenna. We analyze the performance of the uplink multiuser detection and downlink transmitter op...

In this paper we develop a framework for competition of future operators likely to operate in a mixed commons/property-rights regime under the regulation of a spectrum policy server (SPS). The operators dynamically compete for customers as well as portions of available spectrum. The operators are charged by the SPS for the amount of bandwidth they...

Doppler radar life sensing has shown promise in medical and security applications, however the problems of motion artifacts and presence of multiple subjects limit the usefulness of this technique. By leveraging recent advances in signal processing and wireless communications technologies, the Doppler radar technique has the potential to overcome t...

To demonstrate a real-time, mobile, peer to peer, ad-hoc networked MIMO system in a realistic tactical environment, the Defense Advanced Research Projects Agency has instituted a program called mobile network MIMO. The first stage of this program is to demonstrate such a system in a rural foliated environment using MIMO equipped nodes in an ad-hoc...

The advances in programmable and reconfigurable radios have rendered feasible transmitter optimization schemes that can greatly improve the performance of multiple-antenna multiuser systems. Reconfigurable radio platforms are particularly suitable for implementation of transmitter optimization at the base station. We consider the downlink of a wire...

We propose a channel state information (CSI) feedback scheme based on unquantized and uncoded (UQ-UC) transmission. We consider a system where a mobile terminal obtains the downlink CSI and feeds it back to the base station using an uplink feedback channel. If the downlink channel is an independent Rayleigh fading channel, then the CSI may be viewe...

In single-user MIMO communication, the first-order throughput scaling is determined by the smallest of the number of transmit and receive antennas. This typically renders terminals the constraining bottleneck. In a multiuser downlink, this bottleneck can be bypassed by having the base station communicate with multiple terminals simultaneously, in w...

An extensive campaign to characterize the multi-antenna radio propagation channel between two ground based platforms was conducted in a rural area of Lakehurst, NJ. Dozens of links with ground level transmitter and receiver arrays were characterized in mixed wooded/open terrain over ranges of up to 4 km. MIMO capacity was computed for an 8×10 MIMO...

We propose a channel state information (CSI) feedback scheme based on unquantized and uncoded (UQ-UC) transmission. We consider a system where a mobile terminal obtains the downlink CSI and feeds it back to the base station using an uplink feedback channel. If the downlink channel is an independent Rayleigh fading channel, then the CSI may be viewe...

In this paper we present multiple antenna transmitter optimization schemes that are based on linear transformations and transmit power optimization, while keeping the average transmit power conserved. We consider the downlink of a wireless system with multiple transmit antennas at the base station and a number of mobile terminals (i.e., users) each...

In single-user MIMO communication, the first-order throughput scaling is determined by the smaller of the number of transmit and receive antennas. This typically renders terminals the constraining bottleneck. In a multiuser downlink, this bottleneck can be bypassed by having the base station communicate with multiple terminals simultaneously, where...

We analyze the effects of pilot-assisted channel estimation on achievable data rates (lower bound on information capacity) over a frequency flat time-varying channel. Under a block-fading channel model, the effects of the estimation error are evaluated in the case of the estimates being available at the receiver only (open loop) and in the case whe...

We present multiple antenna transmitter optimization (i.e., spatial prefiltering) schemes that are based on linear transformations and transmit power optimization (keeping average transmit power conserved). We consider the downlink of a wireless system with multiple transmit antennas at the base station and a number of mobile terminals (i.e., users...

In this paper, a multiple-input-multiple-output (MIMO) extension for a third-generation (3G) wireless system is described. The integration of MIMO concepts within the existing UMTS standard and the associated space-time RAKE receiver are explained. An analysis is followed by a description of an actual experimental MIMO transmitter and receiver arch...

An over-the-air demonstration of unsupervised (blind) multiple-input/multiple output (MIMO) channel deconvolution is presented. The results were obtained in an indoor multiple antenna (BLAST) context. A suitable unsupervised MIMO technique was used in order to avoid the effective reduction of spectral efficiency caused by the use of channel trainin...

We propose a blind successive interference cancellation receiver for asynchronous direct-sequence code-division multiple-access (DS-CDMA) systems using a maximum mean energy (MME) optimization criterion. The covariance matrix of the received vector is used in conjunction with the MME criterion to realize a blind successive interference canceler tha...

In this paper we propose a multistage nonlinear blind interference cancellation (MS-NL-BIC) receiver for direct-sequence code-division multiple-access (DS-CDMA) systems. The receiver uses higher order statistics of the received baseband signal. Specifically, we use the second and fourth moments of the received signal to determine a component of the...

In this paper we analyze the effects of channel re-sponse estimation error of a frequency-flat time-varying channel on system capacity. Using a block-fading channel model, where the block length corre-sponds to the channel coherence time, we consider two pilot based approaches for the estimation. The first approach uses a single pilot symbol per bl...

In this paper we propose a multistage nonlinear blind interference cancellation (MS-NL-BIC) receiver for direct-sequence code-division multiple-access (DS-CDMA) systems. The receiver uses higher order statistics of the received baseband signal. Specifically, we use the second and fourth moments of the received signal to determine a component of the...

In this paper we propose a multistage nonlinear blind interference cancellation (MS-NL-BIC) receiver for direct-sequence code-division multiple-access (DS-CDMA) systems. The receiver uses higher order statistics of the received baseband signal. Specifically, we use the second and fourth moments of the received signal to determine a component of the...

In this paper we propose a blind inter-ference cancellation and channel estimation receiver for direct-sequence code-division multiple-access (DS-CDMA) systems, which assumes knowledge of only the nominal desired user signature sequence. It is a multistage nonlinear blind interference cancellation and channel estimation receiver that uses higher or...

We evaluate the performance of the VBLAST (vertical Bell Labs layered space-time) receiver algorithm in multiple-transmitter/multiple-receiver (MTMR) cellular W-CDMA systems. We assume that the VBLAST algorithm is executed on a symbol level (i.e., on the despread received signal), following a conventional bank of matched filters (correlators). Also...

BLAST has been shown to provide high capacity wireless communications by using multiple antennas at both transmitter and receiver. We have built a narrowband wireless BLAST testbed with multiple transmit and receive antennas. We examine the performance of the VBLAST by choosing the antenna configurations and performing link adaptation. It is shown...

A multiple antenna system has been shown to provide high capacity wireless communications. We have built a narrowband wireless BLAST testbed with multiple transmit and receive antennas. To validate the effectiveness of the testbed and BLAST technique, we transmit H.263 video at a rate of 230 kbps. The video performance under different channel condi...

In this paper we propose a blind in-terference cancellation (IC) receiver for asynchronous direct-sequence code-division multiple-access (DS-CDMA) systems using a maximum mean energy (MME) optimization criterion. The simulation re-sults show that this scheme offers performance gains over the well known blind receiver that is based on the minimum me...