Special Issue on Coding and Signal Processing

Biglieri, Ezio,Tarokh, Vahid,Simon, Marvin K. The Korean Institute of Communications and Informa 2003 Journal of communications and networks Vol.5 No.2

Linear--Quadratic Detectors for Spectrum Sensing

Ezio Biglieri,Marco Lops 한국통신학회 2014 Journal of communications and networks Vol.16 No.5

Spectrum sensing for cognitive-radio applications mayuse a matched-filter detector (in the presence of full knowledge ofthe signal that may be transmitted by the primary user) or an energydetector (when that knowledge is missing). An intermediatesituation occurs when the primary signal is imperfectly known, inwhich case we advocate the use of a linear–quadratic detector. Weshow how this detector can be designed by maximizing its deflection,and, using moment-bound theory, we examine its robustnessto the variations of the actual probability distribution of the inaccuratelyknown primary signal.

Prioritized Resource Allocation inWireless Spectrum Pooling

Ezio Biglieri,Angel Lozano,Nabil Alrajeh 한국통신학회 2012 Journal of communications and networks Vol.14 No.5

A standard paradigm for the allocation of wireless resources in communication demands symmetry, whereby all users are assumed to be on equal footing and hence get equal shares of communication capabilities. However, there are situations in which “prime users” should be given higher priority, as for example in the transmission of emergency messages. In this paper, we examine a prioritization policy that can be implemented at the physical layer. In particular, we evaluate the performance of a prioritized transmission scheme based on spectrum pooling and on the assignment of higher signal-to-noise ratio channels to higher-priority users. This performance is compared to that of unprioritized (or “symmetric”)schemes, and the impact of prioritization on the unprioritized users is discussed.

The Robustness of Coding and Modulation for Body-Area Networks

Ezio Biglieri,Nabil Alrajeh 한국통신학회 2014 Journal of communications and networks Vol.16 No.3

We consider transmission over body area networks. Dueto the difficulty in assessing an accurate statistical model valid formultiple scenarios, we advocate a system design technique favoringrobustness.Our approach, which is based on results in [12] andgeneralizes them, examines the variation of a performance metricwhen the nominal statistical distribution of fading is replacedby the worst distribution within a given Kullback–Leibler divergencefrom it. The sensitivity of the performance metric to the divergencefrom the nominal distribution can be used as an indicationof the design robustness. This concept is applied by evaluatingthe error probability of binary uncoded modulation and the outageprobability—the first parameter is useful to assess system performancewith no error-control coding, while the second reflects theperformance when a near-optimal code is used. The usefulness ofchannel coding can be assessed by comparing its robustness withthat of uncoded transmission.

Spectrum Sensing Under Uncertain Channel Modeling

Biglieri, Ezio The Korea Institute of Information and Commucation 2012 Journal of communications and networks Vol.14 No.3

We examine spectrum sensing in a situation of uncertain channel model. In particular, we assume that, besides additive noise, the observed signal contains an interference term whose probability distribution is unknown, and only its range and maximum power are known. We discuss the evaluation of the detector performance and its design in this situation. Although this paper specifically deals with the design of spectrum sensors, its scope is wider, as the applicability of its results extends to a general class of problems that may arise in the design of receivers whenever there is uncertainty about how to model the environment in which one is expected to operate. The theory expounded here allows one to determine the performance of a receiver, by combining the available (objective) probabilistic information with (subjective) information describing the designer's attitude.

Large-System Analyses of Multiple-Antenna System Capacities

Biglieri, Ezio,Taricco, Giorgio The Korea Institute of Information and Commucation 2003 Journal of communications and networks Vol.5 No.2

Asymptotic theorems are very commonly used in probability. For systems whose performance depends on a set of n random parameters, asymptotic analyses for n${\to}{\infty}$ are often used to simplify calculations and obtain results yielding useful hints at the behavior of the system for finite n. These asymptotic analyses are especially useful whenever the convergence to the asymptotic results is so fast that even for moderate n they yield results close to the true values. This tutorial paper illustrates this principle by applying it to capacity calculations of multiple-antenna systems.

Prioritized Resource Allocation in Wireless Spectrum Pooling

Biglieri, Ezio,Lozano, Angel,Alrajeh, Nabil The Korea Institute of Information and Commucation 2012 Journal of communications and networks Vol.14 No.5

A standard paradigm for the allocation of wireless resources in communication demands symmetry, whereby all users are assumed to be on equal footing and hence get equal shares of communication capabilities. However, there are situations in which "prime users" should be given higher priority, as for example in the transmission of emergency messages. In this paper, we examine a prioritization policy that can be implemented at the physical layer. In particular, we evaluate the performance of a prioritized transmission scheme based on spectrum pooling and on the assignment of higher signal-to-noise ratio channels to higher-priority users. This performance is compared to that of unprioritized (or "symmetric") schemes, and the impact of prioritization on the unprioritized users is discussed.

Spectrum Sensing Under Uncertain Channel Modeling

Ezio Biglieri 한국통신학회 2012 Journal of communications and networks Vol.14 No.3

We examine spectrum sensing in a situation of uncertain channel model. In particular, we assume that, besides additive noise, the observed signal contains an interference term whose probability distribution is unknown, and only its range and maximum power are known. We discuss the evaluation of the detector performance and its design in this situation. Although this paper specifically deals with the design of spectrum sensors, its scope is wider, as the applicability of its results extends to a general class of problems that may arise in the design of receivers whenever there is uncertainty about how to model the environment in which one is expected to operate. The theory expounded here allows one to determine the performance of a receiver, by combining the available (objective) probabilistic information with (subjective) information describing the designer’s attitude.

Interference Priority: A New Scheme for Prioritized Resource Allocation in Wireless

Angel Lozano,Ezio Biglieri,Nabil Alrajeh 한국통신학회 2012 Journal of communications and networks Vol.14 No.5

A standard paradigm for the allocation of wireless resources in communication demands symmetry, that is, all users are assumed to be on equal footing and hence get equal shares of the system’s communication capabilities. However, there are situations in which “prime users” should be given priority, as for example in the transmission of emergency messages. We examine prioritization policies that could be implemented at the physical layer and propose a new one, termed interference priority (IP), which is shown to have excellent performance. We evaluate the performance of these prioritization techniques both in controlled settings and within the context of a full cellular system and discuss the impact of prioritized use of resources on the unprioritized users.

Interference Priority: A New Scheme for Prioritized Resource Allocation in Wireless

Lozano, Angel,Biglieri, Ezio,Alrajeh, Nabil The Korea Institute of Information and Commucation 2012 Journal of communications and networks Vol.14 No.5

A standard paradigm for the allocation of wireless resources in communication demands symmetry, that is, all users are assumed to be on equal footing and hence get equal shares of the system's communication capabilities. However, there are situations in which "prime users" should be given priority, as for example in the transmission of emergency messages. We examine prioritization policies that could be implemented at the physical layer and propose a new one, termed interference priority (IP), which is shown to have excellent performance. We evaluate the performance of these prioritization techniques both in controlled settings and within the context of a full cellular system and discuss the impact of prioritized use of resources on the unprioritized users.