Results for "Petar Popovski"

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Ultra-Reliable Communication in 5G Wireless SystemsOct 16 2014Wireless 5G systems will not only be "4G, but faster". One of the novel features discussed in relation to 5G is Ultra-Reliable Communication (URC), an operation mode not present in today's wireless systems. URC refers to provision of certain level of ... More
Delayed Channel State Information: Incremental Redundancy with Backtrack RetransmissionJan 27 2014In many practical wireless systems, the Signal-to-Interference-and-Noise Ratio (SINR) that is applicable to a certain transmission, referred to as Channel State Information (CSI), can only be learned after the transmission has taken place and is thereby ... More
Protocol Coding through Reordering of User Resources: Applications and Capacity ResultsNov 26 2010Feb 01 2012While there are continuous efforts to introduce new communication systems and standards, it is legitimate to ask the question: how can one send additional bits by minimally changing the systems that are already operating? This is of a significant practical ... More
Physical Network Coding in Two-Way Wireless Relay ChannelsJul 03 2007It has recently been recognized that the wireless networks represent a fertile ground for devising communication modes based on network coding. A particularly suitable application of the network coding arises for the two--way relay channels, where two ... More
Coded Slotted ALOHA with Varying Packet Loss Rate across UsersJun 29 2013The recent research has established an analogy between successive interference cancellation in slotted ALOHA framework and iterative belief-propagation erasure-decoding, which has opened the possibility to enhance random access protocols by utilizing ... More
Protocol Coding through Reordering of User Resources, Part I: Capacity ResultsFeb 01 2012The vast existing wireless infrastructure features a variety of systems and standards. It is of significant practical value to introduce new features and devices without changing the physical layer/hardware infrastructure, but upgrade it only in software. ... More
Zero-Outage Cellular Downlink with Fixed-Rate D2D UnderlayApr 28 2014Dec 30 2014Two of the emerging trends in wireless cellular systems are Device-to-Device (D2D) and Machine-to-Machine (M2M) communications. D2D enables efficient reuse of the licensed spectrum to support localized transmissions, while M2M connections are often characterized ... More
Network-Assisted Device-to-Device (D2D) Direct Proximity Discovery with Underlay CommunicationAug 13 2015Device-to-Device communications are expected to play an important role in current and future cellular generations, by increasing the spatial reuse of spectrum resources and enabling lower latency communication links. This paradigm has two fundamental ... More
Power Talk for Multibus DC MicroGrids: Creating and Optimizing Communication ChannelsSep 26 2016We study a communication framework for nonlinear multibus DC MicroGrids based on a deliberate modification of the parameters of the primary control and termed power talk. We assess the case in which the information is modulated in the deviations of reference ... More
Random Access Protocols with Collision Resolution in a Noncoherent SettingSep 29 2014Dec 29 2014Wireless systems are increasingly used for Machine-Type Communication (MTC), where the users sporadically send very short messages. In such a setting, the overhead imposed by channel estimation is substantial, thereby demanding noncoherent communication. ... More
Exploiting Capture Effect in Frameless ALOHA for Massive Wireless Random AccessJan 08 2014The analogies between successive interference cancellation (SIC) in slotted ALOHA framework and iterative belief-propagation erasure-decoding, established recently, enabled the application of the erasure-coding theory and tools to design random access ... More
Coded Splitting Tree ProtocolsJan 30 2013This paper presents a novel approach to multiple access control called coded splitting tree protocol. The approach builds on the known tree splitting protocols, code structure and successive interference cancellation (SIC). Several instances of the tree ... More
On the Role of Feedback in LT CodesDec 13 2010This paper concerns application of feedback in LT codes. The considered type of feedback is acknowledgments, where information on which symbols have been decoded is given to the transmitter. We identify an important adaptive mechanism in standard LT codes, ... More
Efficient LTE Access with Collision Resolution for Massive M2M CommunicationsOct 24 2014LTE random access procedure performs satisfactorily in case of asynchronous, uncorrelated traffic arrivals. However, when the arrivals are correlated and arrive synchronously, the performance of the random access channel (RACH) is drastically reduced, ... More
Reliable Reporting for Massive M2M Communications with Periodic Resource PoolingApr 04 2014This letter considers a wireless M2M communication scenario with a massive number of M2M devices. Each device needs to send its reports within a given deadline and with certain reliability, e. g. 99.99%. A pool of resources available to all M2M devices ... More
Reengineering GSM/GPRS Towards a Dedicated Network for Massive Smart MeteringOct 24 2014GSM is a synonym for a major success in wireless technology, achieving widespread use and high technology ma- turity. However, its future is questionable, as many stakeholders indicate that the GSM spectrum should be refarmed for LTE. On the other hand, ... More
Frameless ALOHA Protocol for Wireless NetworksMay 18 2012Oct 10 2012We propose a novel distributed random access scheme for wireless networks based on slotted ALOHA, motivated by the analogies between successive interference cancellation and iterative belief-propagation decoding on erasure channels. The proposed scheme ... More
Modemless Multiple Access Communications over Powerlines for DC Microgrid ControlSep 14 2016We present a communication solution tailored specifically for DC microgrids (MGs) that exploits: (i) the communication potential residing in power electronic converters interfacing distributed generators to powerlines and (ii) the multiple access nature ... More
Wirelessly Powered Communication Networks with Short PacketsOct 24 2016Nov 01 2016Wirelessly powered communications will entail short packets due to naturally small payloads, low-latency requirements and/or insufficient energy resources to support longer transmissions. In this paper, a wirelessly powered communication system is investigated ... More
Identifying Randomly Activated Users via Sign-Compute-Resolve on GraphsMar 07 2016In this paper we treat the problem of identification of a subset of active users in a set of a large number of potentially active users. The users from the subset are activated randomly, such that the access point (AP) does not know the subset or its ... More
Code-Expanded Random Access for Machine-Type CommunicationsJul 02 2012The random access methods used for support of machine-type communications (MTC) in current cellular standards are derivatives of traditional framed slotted ALOHA and therefore do not support high user loads efficiently. Motivated by the random access ... More
Cognitive Multiple Access Network with Outage Margin in the Primary SystemFeb 12 2011This paper investigates the problem of spectrally efficient operation of a multiuser uplink cognitive radio system in the presence of a single primary link. The secondary system applies opportunistic interference cancelation (OIC) and decode the primary ... More
Rate Adaptation for Cognitive Radio under Interference from Primary Spectrum UserMay 09 2007A cognitive radio can operate as a secondary system in a given spectrum. This operation should use limited power in order not to disturb the communication by primary spectrum user. Under such conditions, in this paper we investigate how to maximize the ... More
Software-Defined Microgrid Control for Resilience Against Cyber AttacksFeb 08 2018Microgrids (MGs) rely on networked control supported by off-the-shelf wireless communications. This makes them vulnerable to cyber-attacks, such as denial-of-service (DoS). In this paper, we mitigate those attacks by applying the concepts of (i) separation ... More
Wirelessly Powered Communication Networks with Short PacketsOct 24 2016Wirelessly powered communications will entail short packets due to naturally small payloads, low-latency requirements and/or insufficient energy resources to support longer transmissions. In this paper, a wirelessly powered communication system is investigated ... More
Random Access for Machine-Type Communication based on Bloom FilteringNov 16 2015Aug 30 2016We present a random access method inspired on Bloom filters that is suited for Machine-Type Communications (MTC). Each accessing device sends a \emph{signature} during the contention process. A signature is constructed using the Bloom filtering method ... More
Interference Spins: Scheduling of Multiple Interfering Two-Way Wireless LinksJan 06 2015Feb 04 2015Two-way is a dominant mode of communication in wireless systems. Departing from the tradition to optimize each transmission direction separately, recent work has demonstrated that, for time-division duplex (TDD) systems, optimizing the schedule of the ... More
All-to-all Broadcast for Vehicular Networks Based on Coded Slotted ALOHAJan 14 2015Jan 26 2015We propose an uncoordinated all-to-all broadcast protocol for periodic messages in vehicular networks based on coded slotted ALOHA (CSA). Unlike classical CSA, each user acts as both transmitter and receiver in a half-duplex mode. As in CSA, each user ... More
Error Floor Analysis of Coded Slotted ALOHA over Packet Erasure ChannelsDec 09 2014We present a framework for the analysis of the error floor of coded slotted ALOHA (CSA) for finite frame lengths over the packet erasure channel. The error floor is caused by stopping sets in the corresponding bipartite graph, whose enumeration is, in ... More
Random Access in C-RAN for User Activity Detection with Limited-Capacity FronthaulJun 07 2016Sep 02 2016Cloud-Radio Access Network (C-RAN) is characterized by a hierarchical structure in which the baseband processing functionalities of remote radio heads (RRHs) are implemented by means of cloud computing at a Central Unit (CU). A key limitation of C-RANs ... More
Analysis of the LTE Access Reservation Protocol for Real-Time TrafficJan 11 2013Jun 11 2013LTE is increasingly seen as a system for serving real-time Machine-to-Machine (M2M) communication needs. The asynchronous M2M user access in LTE is obtained through a two-phase access reservation protocol (contention and data phase). Existing analysis ... More
Coded Random Access: How Coding Theory Helps to Build Random Access ProtocolsMay 16 2014The rise of machine-to-machine communications has rekindled the interest in random access protocols and their use to support a massive number of uncoordinatedly transmitting devices. The classic ALOHA approach is developed under a collision model, where ... More
Coded Network Function Virtualization: Fault Tolerance via In-Network CodingAug 12 2016Sep 16 2016Network Function Virtualization (NFV) prescribes the instantiation of network functions on general-purpose network devices, such as servers and switches. While yielding a more flexible and cost-effective network architecture, NFV is potentially limited ... More
HARQ Buffer Management: An Information-Theoretic ViewJan 25 2015Mar 30 2015A key practical constraint on the design of Hybrid automatic repeat request (HARQ) schemes is the size of the on-chip buffer that is available at the receiver to store previously received packets. In fact, in modern wireless standards such as LTE and ... More
Performance Limits of Energy Detection Systems with Massive Receiver ArraysNov 30 2016Energy detection (ED) is an attractive technique for symbol detection at receivers equipped with a large number of antennas, for example in millimeter wave communication systems. This paper investigates the performance bounds of ED with pulse amplitude ... More
Making the Grid Truly Smart: Autonomous System Identification in "Modemless" DC MicroGridsMar 30 2017We introduce novel framework for autonomous learning of the own configuration in direct current (DC) MicroGrids (MG) with high penetration of power electronic converters and without access to an external communication system. The framework is implemented ... More
Distributed Estimation of the Operating State of a Single-Bus DC MicroGrid without an External Communication InterfaceSep 14 2016We propose a decentralized Maximum Likelihood solution for estimating the stochastic renewable power generation and demand in single bus Direct Current (DC) MicroGrids (MGs), with high penetration of droop controlled power electronic converters. The solution ... More
ALOHA Random Access that Operates as a Rateless CodeAug 07 2013Various applications of wireless Machine-to-Machine (M2M) communications have rekindled the research interest in random access protocols, suitable to support a large number of connected devices. Slotted ALOHA and its derivatives represent a simple solution ... More
Massive Machine-type Communications in 5G: Physical and MAC-layer solutionsJun 13 2016Machine-type communications (MTC) are expected to play an essential role within future 5G systems. In the FP7 project METIS, MTC has been further classified into "massive Machine-Type Communication" (mMTC) and "ultra-reliable Machine-Type Communication" ... More
Probabilistic Handshake in All-to-all Broadcast Coded Slotted ALOHAApr 17 2015We propose a probabilistic handshake mechanism for all-to-all broadcast coded slotted ALOHA. We consider a fully connected network where each user acts as both transmitter and receiver in a half-duplex mode. Users attempt to exchange messages with each ... More
Two-Way Communication with Energy ExchangeApr 09 2012The conventional assumption made in the design of communication systems is that the energy used to transfer information between a sender and a recipient cannot be reused for future communication tasks. A notable exception to this norm is given by passive ... More
Wireless Secrecy in Cellular Systems with Infrastructure--Aided CooperationMay 03 2008In cellular systems, confidentiality of uplink transmission with respect to eavesdropping terminals can be ensured by creating intentional inteference via scheduling of concurrent downlink transmissions. In this paper, this basic idea is explored from ... More
On the Impact of Wireless Jamming on the Distributed Secondary Microgrid ControlSep 22 2016The secondary control in direct current microgrids (MGs) is used to restore the voltage deviations caused by the primary droop control, where the latter is implemented locally in each distributed generator and reacts to load variations. Numerous recent ... More
CoMPflex: CoMP for In-Band Wireless Full DuplexJul 30 2015Oct 30 2015In this letter we consider emulation of a Full Duplex (FD) cellular base station (BS) by using two spatially separated and coordinated half duplex (HD) BSs. The proposed system is termed CoMPflex (CoMP for In-Band Wireless Full Duplex) and at a given ... More
Why to Decouple the Uplink and Downlink in Cellular Networks and How To Do ItMar 23 2015Ever since the inception of mobile telephony, the downlink and uplink of cellular networks have been coupled, i.e. mobile terminals have been constrained to associate with the same base station (BS) in both the downlink and uplink directions. New trends ... More
Capacity Analysis of Decoupled Downlink and Uplink Access in 5G Heterogeneous SystemsOct 27 2014Our traditional notion of a cell is changing dramatically given the increasing degree of heterogeneity in 4G and emerging 5G systems. Rather than belonging to a specific cell, a device would choose the most suitable connection from the plethora of connections ... More
Five Disruptive Technology Directions for 5GDec 01 2013New research directions will lead to fundamental changes in the design of future 5th generation (5G) cellular networks. This paper describes five technologies that could lead to both architectural and component disruptive design changes: device-centric ... More
Assessment of LTE Wireless Access for Monitoring of Energy Distribution in the Smart GridAug 11 2015Nov 30 2015While LTE is becoming widely rolled out for human-type services, it is also a promising solution for cost-efficient connectivity of the smart grid monitoring equipment. This is a type of machine-to-machine (M2M) traffic that consists mainly of sporadic ... More
What Can Wireless Cellular Technologies Do about the Upcoming Smart Metering Traffic?Feb 04 2015Jul 01 2015The introduction of smart electricity meters with cellular radio interface puts an additional load on the wireless cellular networks. Currently, these meters are designed for low duty cycle billing and occasional system check, which generates a low-rate ... More
Zero-Error Capacity of a Class of Timing ChannelsNov 06 2013Aug 24 2014We analyze the problem of zero-error communication through timing channels that can be interpreted as discrete-time queues with bounded waiting times. The channel model includes the following assumptions: 1) Time is slotted, 2) at most $ N $ "particles" ... More
Reliable Uplink Communication through Double Association in Wireless Heterogeneous NetworksMay 08 2015Apr 03 2016We investigate methods for network association that improve the reliability of uplink transmissions in dense wireless heterogeneous networks. The stochastic geometry analysis shows that the double association, in which an uplink transmission is transmitted ... More
Low-Rate Machine-Type Communication via Wireless Device-to-Device (D2D) LinksMay 29 2013Wireless cellular networks feature two emerging technological trends. The first is the direct Device-to-Device (D2D) communications, which enables direct links between the wireless devices that reutilize the cellular spectrum and radio interface. The ... More
Reliable Reception of Wireless Metering Data with Protocol CodingMay 21 2013Stationary collectors reading wireless, battery powered smart meters, often operate in harsh channel conditions to cut network installation cost to a minimum, challenging the individual link to each meter. The desired performance measure is reliable reception ... More
Block-Fading Channels with Delayed CSIT at Finite BlocklengthJan 28 2014In many wireless systems, the channel state information at the transmitter (CSIT) can not be learned until after a transmission has taken place and is thereby outdated. In this paper, we study the benefits of delayed CSIT on a block-fading channel at ... More
Downlink Transmission of Short Packets: Framing and Control Information RevisitedMay 06 2016Cellular wireless systems rely on frame-based transmissions. The frame design is conventionally based on heuristics, consisting of a frame header and a data part. The frame header contains control information that provides pointers to the messages within ... More
Spectrum Pooling in MmWave Networks: Opportunities, Challenges, and EnablersMar 03 2016Motivated by the intrinsic characteristics of mmWave technologies, we discuss the possibility of an authorization regime that allows spectrum sharing between multiple operators, also referred to as spectrum pooling. In particular, considering user rate ... More
Latency Analysis of Systems with Multiple Interfaces for Ultra-Reliable M2M CommunicationMay 07 2016One of the ways to satisfy the requirements of ultra-reliable low latency communication for mission critical Machine-type Communications (MTC) applications is to integrate multiple communication interfaces. In order to estimate the performance in terms ... More
Sign-Compute-Resolve for Tree Splitting Random AccessFeb 08 2016We present an approach to random access that is based on three elements: physical-layer network coding (PLNC), signature codes and tree splitting. In presence of a collision, physical-layer network coding enables the receiver to decode, i.e. compute the ... More
Decoupled Uplink and Downlink in a Wireless System with Buffer-Aided RelayingSep 21 2016Sep 22 2016The paper treats a multiuser relay scenario where multiple user equipments (UEs) have a two-way communication with a common Base Station (BS) in the presence of a buffer-equipped Relay Station (RS). Each of the uplink (UL) and downlink (DL) transmission ... More
Sign-Compute-Resolve for Random AccessSep 24 2014We present an approach to random access that is based on three elements: physical-layer network coding, signature codes and tree splitting. Upon occurrence of a collision, physical-layer network coding enables the receiver to decode the sum of the information ... More
Design and Analysis of LT Codes with Decreasing Ripple SizeNov 09 2010Jun 07 2012In this paper we propose a new design of LT codes, which decreases the amount of necessary overhead in comparison to existing designs. The design focuses on a parameter of the LT decoding process called the ripple size. This parameter was also a key element ... More
Analysis of LT Codes with Unequal Recovery TimeApr 20 2012In this paper we analyze a specific class of rateless codes, called LT codes with unequal recovery time. These codes provide the option of prioritizing different segments of the transmitted data over other. The result is that segments are decoded in stages ... More
Cognitive Access-Transmission Policies under a Primary ARQ process via Chain DecodingSep 26 2015This paper introduces a novel technique that enables access by a cognitive secondary user (SU) to a spectrum occupied by an incumbent primary user (PU) that employs Type-I Hybrid ARQ. The technique allows the SU to perform selective retransmissions of ... More
A Study of Trade-off between Opportunistic Resource Allocation and Interference Alignment in Femtocell ScenariosApr 20 2012One of the main problems in wireless heterogeneous networks is interference between macro- and femto-cells. Using Orthogonal Frequency-Division Multiple Access (OFDMA) to create multiple frequency orthogonal sub-channels, this interference can be completely ... More
Analysis of the Decoupled Access for Downlink and Uplink in Wireless Heterogeneous NetworksJul 02 2014Oct 21 2014Wireless cellular networks evolve towards a heterogeneous infrastructure, featuring multiple types of Base Stations (BSs), such as Femto BSs (FBSs) and Macro BSs (MBSs). A wireless device observes multiple points (BSs) through which it can access the ... More
Efficiency Analysis of Decoupled Downlink and Uplink Access in Heterogeneous NetworksDec 04 2014This paper analyzes two-tier heterogeneous cellular network with decoupled downlink and uplink access. The basic performance benefits of uplink/downlink decoupling have been recently introduced. Here we provide a more elaborate treatment of the decoupling ... More
Buffer-Aided Relaying with Adaptive Link SelectionFeb 24 2012Oct 13 2012In this paper, we consider a simple network consisting of a source, a half-duplex decode-and-forward relay, and a destination. We propose a new relaying protocol employing adaptive link selection, i.e., in any given time slot, based on the channel state ... More
Using Wireless Network Coding to Replace a Wired with Wireless BackhaulApr 14 2014Cellular networks are evolving towards dense deployment of small cells. This in turn demands flexible and efficient backhauling solutions. A viable solution that reuses the same spectrum is wireless backhaul where the Small Base Station (SBS) acts as ... More
On Buffer-Aided Multiple-Access Relay ChannelSep 21 2016Sep 22 2016The paper treats uplink scenario where M user equipments (UEs) send to a Base Station (BS), possibly via a common Relay Station (RS) that is equipped with a buffer. This is a multiple-access relay channel (MARC) aided by a buffer. We devise a protocol ... More
Physical Layer Network Coding: A Cautionary Story with Interference and Spatial ReservationNov 06 2013Physical layer network coding (PLNC) has the potential to improve throughput of multi-hop networks. However, most of the works are focused on the simple, three-node model with two-way relaying, not taking into account the fact that there can be other ... More
5G Ultra-Reliable Vehicular CommunicationOct 05 2015Oct 08 2015Applications enabled by Cooperative Intelligent Transport Systems (C-ITS) represent a major step towards making the road transport system safer and more efficient (green), and thus suited for a sustainable future. Wireless communication between vehicles ... More
Towards Massive, Ultra-Reliable, and Low-Latency Wireless Communication with Short PacketsApr 24 2015Mar 01 2016Most of the recent advances in the design of high-speed wireless systems are based on information-theoretic principles that demonstrate how to efficiently transmit long data packets. However, the upcoming wireless systems, notably the 5G system, will ... More
Protocol Coding through Reordering of User Resources, Part II: Practical Coding StrategiesFeb 01 2012We use the term protocol coding to denote the communication strategies in which information is encoded through the actions taken by a certain communication protocol. In this work we investigate strategies for protocol coding via combinatorial ordering ... More
Delay Minimization in Real-time Communications with Joint Buffering and CodingOct 14 2016We present a closed-form expression for the minimal delay that is achievable in a setting that combines a buffer and an erasure code, used to mitigate the packet delay variance. The erasure code is modeled according to the recent information-theoretic ... More
Massive M2M Access with Reliability Guarantees in LTE SystemsFeb 10 2015Machine-to-Machine (M2M) communications are one of the major drivers of the cellular network evolution towards 5G systems. One of the key challenges is on how to provide reliability guarantees to each accessing device in a situation in which there is ... More
Aggregation and Trunking of M2M Traffic via D2D ConnectionsFeb 05 2015Machine-to-Machine (M2M) communications is one of the key enablers of the Internet of Things (IoT). Billions of devices are expected to be deployed in the next future for novel M2M applications demanding ubiquitous access and global connectivity. In order ... More
Joint Estimation and Contention-Resolution Protocol for Wireless Random AccessOct 02 2012We propose a contention-based random-access protocol, designed for wireless networks where the number of users is not a priori known. The protocol operates in rounds divided into equal-duration slots, performing at the same time estimation of the number ... More
Massive MIMO for Crowd Scenarios: A Solution Based on Random AccessMay 21 2015This paper presents a new approach to intra-cell pilot contamination in crowded massive MIMO scenarios. The approach relies on two essential properties of a massive MIMO system, namely near-orthogonality between user channels and near-stability of channel ... More
Power Talk in DC Micro Grids: Constellation Design and Error Probability PerformanceJul 09 2015Power talk is a novel concept for communication among units in a Micro Grid (MG), where information is sent by using power electronics as modems and the common bus of the MG as a communication medium. The technique is implemented by modifying the droop ... More
Blahut-Arimoto Algorithm and Code Design for Action-Dependent Source Coding ProblemsJan 25 2013The source coding problem with action-dependent side information at the decoder has recently been introduced to model data acquisition in resource-constrained systems. In this paper, an efficient algorithm for numerical computation of the rate-distortion-cost ... More
Design and Performance Analysis of Non-Coherent Detection Systems with Massive Receiver ArraysJun 20 2016Harvesting the gain of a large number of antennas in a mmWave band has mainly been relying on the costly operation of channel state information (CSI) acquisition and cumbersome phase shifters. Recent works have started to investigate the possibility to ... More
Random Access for Massive MIMO Systems with Intra-Cell Pilot ContaminationSep 28 2015Jun 07 2016Massive MIMO systems, where the base stations are equipped with hundreds of antenna elements, are an attractive way to attain unprecedented spectral efficiency in future wireless networks. In the "classical" massive MIMO setting, the terminals are assumed ... More
Variable-Length Coding with Stop-Feedback for the Common-Message Broadcast Channel in the Nonasymptotic RegimeJul 12 2016We investigate the maximum coding rate for a given average blocklength and error probability over a K-user discrete memoryless broadcast channel for the scenario where a common message is transmitted using variable-length stop-feedback codes. For the ... More
Design Aspects of Short Range Millimeter Wave Networks: A MAC Layer PerspectiveSep 24 2015Increased density of wireless devices, ever growing demands for extremely high data rate, and spectrum scarcity at microwave bands make the millimeter wave (mmWave) frequencies an important player in future wireless networks. However, mmWave communication ... More
Cognitive Access Policies under a Primary ARQ process via Forward-Backward Interference CancellationJan 30 2013This paper introduces a novel technique for access by a cognitive Secondary User (SU) using best-effort transmission to a spectrum with an incumbent Primary User (PU), which uses Type-I Hybrid ARQ. The technique leverages the primary ARQ protocol to perform ... More
Reliable Identification of RFID Tags Using Multiple Independent Reader SessionsApr 16 2009Radio Frequency Identification (RFID) systems are gaining momentum in various applications of logistics, inventory, etc. A generic problem in such systems is to ensure that the RFID readers can reliably read a set of RFID tags, such that the probability ... More
Coded Pilot Access: A Random Access Solution for Massive MIMO SystemsMay 19 2016We present a novel access protocol for crowd scenarios in massive MIMO (Multiple-input multiple-output) systems. Crowd scenarios are characterized by a large number of users with intermittent access behavior, whereby orthogonal scheduling is infeasible. ... More
Secure Communication with a Wireless-Powered Friendly JammerDec 01 2014Aug 26 2015In this paper, we propose to use a wireless-powered friendly jammer to enable secure communication between a source node and destination node, in the presence of an eavesdropper. We consider a two-phase communication protocol with fixed-rate transmission. ... More
Ultra-Reliable Cloud Mobile Computing with Service Composition and Superposition CodingJan 15 2016An emerging requirement for 5G systems is the ability to provide wireless ultra-reliable communication (URC) services with close-to-full availability for cloud-based applications. Among such applications, a prominent role is expected to be played by mobile ... More
Broadcasting a Common Message with Variable-Length Stop-Feedback CodesApr 22 2015We investigate the maximum coding rate achievable over a two-user broadcast channel for the scenario where a common message is transmitted using variable-length stop-feedback codes. Specifically, upon decoding the common message, each decoder sends a ... More
Power Distribution of Device-to-Device Communications in Underlaid Cellular NetworksNov 15 2015Device-to-device (D2D) communications have recently emerged as a novel transmission paradigm in wireless cellular networks. D2D transmissions take place concurrently with the usual cellular connections, and thus, controlling the interference brought to ... More
Sum-Rate Optimization in a Two-Way Relay Network with BufferingJul 26 2012A Relay Station (RS) uses a buffer to store and process the received data packets before forwarding them. Recently, the buffer has been exploited in one-way relaying to opportunistically schedule the two different links according to their channel quality. ... More
Random Access Protocol for Massive MIMO: Strongest-User Collision Resolution (SUCR)Dec 01 2015Mar 11 2016Wireless networks with many antennas at the base stations and multiplexing of many users, known as Massive MIMO systems, are key to handle the rapid growth of data traffic. As the number of users increases, the random access in contemporary networks will ... More
Characterization of Coded Random Access with Compressive Sensing based Multi-User DetectionApr 08 2014The emergence of Machine-to-Machine (M2M) communication requires new Medium Access Control (MAC) schemes and physical (PHY) layer concepts to support a massive number of access requests. The concept of coded random access, introduced recently, greatly ... More
Broadcast Coded Slotted ALOHA: A Finite Frame Length AnalysisNov 02 2015May 25 2016We propose an uncoordinated medium access control (MAC) protocol, called all-to-all broadcast coded slotted ALOHA (B-CSA) for reliable all-to-all broadcast with strict latency constraints. In B-CSA, each user acts as both transmitter and receiver in a ... More
Massive Machine-Type Communication (mMTC) Access with Integrated AuthenticationOct 31 2016We present a connection establishment protocol with integrated authentication, suited for Massive Machine-Type Communications (mMTC). The protocol is contention-based and its main feature is that a device contends with a unique signature that also enables ... More
On Wirelessly Powered Communications with Short PacketsSep 16 2016Wireless-powered communications will entail short packets due to naturally small payloads, low latency requirements and/or insufficient energy resources to support longer transmissions. In this paper, a wireless-powered communication system is investigated ... More
A note on mean-value properties of harmonic functions on the hypercubeJun 16 2015Aug 20 2015For functions defined on the $n$-dimensional hypercube $I_n (r) = \{{\bm{x}} \in \mathbb{R}^n ~\vert~ \vert x_i \vert \le r,~ i = 1, 2, \ldots , n\}$ and harmonic therein, we establish certain analogues of Gauss surface and volume mean-value formulas ... More
Transmission Schemes for Four-Way Relaying in Wireless Cellular SystemsSep 26 2012Two-way relaying in wireless systems has initiated a large research effort during the past few years. While one-way relay with a single data flow introduces loss in spectral efficiency due to its half-duplex operation, two-way relaying based on wireless ... More
Fast and Power Efficient Sensor Arbitration: Physical Layer Collision Recovery of Passive RFID TagsDec 16 2010Dec 21 2010This work concerns physical layer collision recovery for cheap sensors with allowed variations in frequency and delay of their communications. The work is presented as a generic, communication theoretic framework and demonstrated using UHF RFID tag technology. ... More