The fifth-generation wireless technology is primarily designed to address a wide range of use cases mainly categorized into the enhanced mobile broadband, ultra-reliable and low-latency communication, and massive machine-type communication segments. To efficiently serve some other use cases whose requirements lie in-between these main use cases, the 3rd generation partnership project (3GPP), in Rel-17, introduce support for the reduced capability new radio (NR) devices known as RedCap with lower cost and complexity compared to legacy 5G devices. The considered complexity reduction techniques are associated with degraded link performance and coverage for the physical channels. Particularly, for the physical downlink control channel (PDCCH), which requires careful consideration, the reduction of the user equipments’ (UEs) complexity and the associated coverage loss can lead to an increase in the PDCCH blocking probability. This, in turn, can impact either the latency or the network capacity depending on the scenario. In this paper, we investigate the PDCCH blocking probability metric for RedCap devices. Specifically, we evaluate the performance of blocking probability in terms of various parameters including the number of users, size of downlink control information, size of control resource set, and the number of PDCCH candidates. Our results demonstrate that the PDCCH blocking probability increases by reducing the number of antenna branches, the number of PDCCH candidates, control resource set, and by increasing the number of scheduled UEs. We also show that the impact of reducing the DCI size is marginal on the PDCCH blocking probability. Finally, we discuss potential solutions and design guidelines for reducing the PDCCH blocking probability.

The 5th generation (5G) new radio (NR) is designed to support a wide range of use cases, requirements, and services from enhanced mobile broadband (eMBB) to ultra-reliable low-latency communications (URLLC). NR signals are designed to meet stringent requirements, and in particular the physical down-link control channel (PDCCH) which requires careful consideration. In this paper, we provide a comprehensive analysis on the PDCCH blocking probability in a network where multiple users need to be scheduled for receiving downlink control information. We evaluate the performance of blocking probability in terms of various network parameters including number of users, size of the control resource set (CORESET), and PDCCH aggregation levels (ALs). Our analysis reveals fundamental tradeoffs and key insights for efficient network design in terms of PDCCH blocking probability.

This paper presents a new method for indicating contiguous resources in the frequency domain where the granularity of frequency resource can vary depending on the size of the actual allocation. The outcome is flexible frequency domain resource allocation (FDRA) where the resource can be finely scheduled when the actual allocation is small or coarsely scheduled when the actual allocation is large. It provides a better tradeoff between scheduling flexibility and overhead reduction as compared to existing approaches. The method reduces the number of bits required to indicate the FDRA in the downlink control information (DCI) and can be applicable for future releases of 5G NR and any future generations of wireless access technologies.

Utilizing the abundant bandwidth in millimeter wave frequency bands is an interesting option to enable wireless communication services with challenging latency and reliability requirements for factory automation. Nevertheless, millimeter wave bands have less favorable propagation properties compared to lower bands, which impacts the coverage negatively. In this paper, we show that millimeter wave bands can fulfill extreme latency and reliability requirements with much higher system capacity than mid-band frequencies by means of beamforming, large antenna arrays, and network densification. This makes millimeter wave bands suitable for providing ultra-reliable low-latency communication services for factory automation. However, we find that small beam misalignments due to channel state information error can degrade the system capacity substantially.

The problem of secret-key based authentication under a privacy constraint on the source sequence is considered. The identifier measurements during authentication are assumed to be controllable via a cost-constrained “action” sequence. Single-letter characterizations of the optimal trade-off among the secret-key rate, storage rate, privacy-leakage rate, and action cost are given for the four problems where noisy or noiseless measurements of the source are enrolled to generate or embed secret keys. The results are relevant for several user-authentication scenarios, including physical and biometric authentications with multiple measurements. Our results include, as special cases, new results for secret-key generation and embedding with action-dependent side information without any privacy constraint on the enrolled source sequence.

We consider the problem of revealing/sharing data in an efficient and secure way via a compact representation. The representation should ensure reliable reconstruction of the desired features/attributes while still preserve privacy of the secret parts of the data. The problem is formulated as a remote lossy source coding with a privacy constraint where the remote source consists of public and secret parts. Inner and outer bounds for the optimal tradeoff region of compression rate, distortion, and privacy leakage rate are given and shown to coincide for some special cases. When specializing the distortion measure to a logarithmic loss function, the resulting rate-distortion-leakage tradeoff for the case of identical side information forms an optimization problem which corresponds to the “secure” version of the so-called information bottleneck.

We consider problems of two-user secret key generation through an intermediate relay. In the untrusted relay setting, the goal is to establish key agreement between the two users at the highest key rate without leaking information about the key to the relay. We characterize inner and outer bounds to the optimal tradeoff between communication and key rates. The inner bound is based on the scheme which involves a combination of binning, network coding, and key aggregation techniques. For the trusted relay setting with a public broadcast link, the optimal communication-key rate tradeoff is provided for a special case where the two sources are available losslessly at the relay.

We consider secure multi-terminal source coding problems in the presence of a public helper. Two main scenarios are studied: 1) source coding with a helper where the coded side information from the helper is eavesdropped by an external eavesdropper, 2) triangular source coding with a helper where the helper is considered as a public terminal. We are interested in how the helper can support the source transmission subject to a constraint on the amount of information leaked due to its public nature. We characterize the tradeoff between transmission rate, incurred distortion, and information leakage rate at the helper/eavesdropper in the form of a rate-distortion-leakage region for various classes of problems.

We consider the problem of identification and authentication based on secret key generation from some usergenerated source data (e.g., a biometric source). The goal is to reliably identify users pre-enrolled in a database as well as authenticate them based on the estimated secret key while preserving the privacy of the enrolled data and of the generated keys. We characterize the optimal tradeoff region of the identification rate, compression rate of the users' source data, information leakage rate, and secret key rate. In particular, we provide a coding strategy based on layered random binning which is shown to be optimal. In addition, we study a related secure identification/authentication problem where an adversary tries to deceive the system using its own data. Here, the optimal tradeoff of the identification rate, compression rate, leakage rate, and exponent of the maximum false acceptance probability is provided. The results reveal a close connection between the optimal secret key rate and the false acceptance exponent of the identification/authentication system.

We consider problems of authentication using secret key generation under a privacy constraint on the enrolled source data. An adversary who has access to the stored description and correlated side information tries to deceive the authentication as well as learn about the source. We characterize the optimal tradeoff between the compression rate of the stored description, the leakage rate of the source data, and the exponent of the adversary's maximum false acceptance probability. The related problem of secret key generation with a privacy constraint is also studied where the optimal tradeoff between the compression rate, leakage rate, and secret key rate is characterized. It reveals a connection between the optimal secret key rate and security of the authentication system.

Two classes of source/channel coding problems, namely, coding with action-dependent side information and coding with additional signal reconstruction are considered in a unified fashion. In the source coding setting, a decoder wishes to reconstruct the source subject to a distortion constraint, while an encoder is required to estimate the decoder's reconstruction reliably. Side information is action-dependent in the sense that its quality and/or availability at the encoder or decoder can be influenced by a cost-constrained action sequence. In the channel coding dual, the decoder wishes to decode both the message and the channel input sequence reliably, and the channel state information available at the encoder or decoder is assumed to depend on the action sequence. We consider discrete memoryless systems and characterize single letter expressions for the rate-distortion-cost function and channel capacity for the respective source and channel coding problems.

We consider the problems of secure lossy source coding with side information in the presence of a passive eavesdropper who has access to the source description. The encoder wishes to compress the source sequence in order to satisfy a distortion criterion at the decoder, while revealing only limited knowledge about the source to the eavesdropper. The side information available to the encoder, the legitimate decoder, or the eavesdropper can be influenced by a cost-constrained action sequence. Three different settings are studied. In the first two settings, we are interested in understanding the influence of the action sequence on the rate-distortion-leakage tradeoff where the action is taken either by the decoder or by the encoder to influence side information at the decoder and eavesdropper. Next, we consider a setting where common action-dependent side information is available securely to both encoder and decoder, and thus can be used for secret key generation. We characterize the optimal rate-distortion-cost-leakage region or the corresponding inner bounds for a discrete memoryless source for above settings. The results are useful in characterizing fundamental limits for example in secure sensor networking and future cyber physical systems.

In this paper, the privacy problem of a parallel distributed detection system vulnerable to an eavesdropper is proposed and studied in the Bayesian formulation. The privacy risk is evaluated by the detection cost of the eavesdropper which is assumed to be informed and greedy. It is shown that the optimal detection strategy of the sensor whose decision is eavesdropped on is a likelihood-ratio test. This fundamental insight allows for the optimization to reuse known algorithms extended to incorporate the privacy constraint. The trade-off between the detection performance and privacy risk is illustrated in a numerical example. The incorporation of physical layer privacy in the system design will lead to trustworthy sensor networks in future.

We consider the problem of lossy source coding with side information under a privacy constraint that the reconstruction sequence at a decoder should be kept secret to a certain extent from another terminal such as an eavesdropper, a sender, or a helper. We are interested in how the reconstruction privacy constraint at a particular terminal affects the rate-distortion tradeoff. In this work, we allow the decoder to use a random mapping, and give inner and outer bounds to the rate-distortion-equivocation region for different cases. In the case where each reconstruction symbol depends only on the source description and current side information symbol, the complete rate-distortion-equivocation region is provided. A binary example illustrating a new tradeoff due to the new privacy constraint, and a gain from the use of randomized decoder is given.

In this paper, we investigate the problem of successive refinement with side information (SI) under secrecy constraint. In particular, under classical successive refinement coding scheme, there are degraded SI sequences Ynand Znat two decoders and Enat the eavesdropper. Based on the status of two switches, three different cases are investigated. In case 1 and 3, the eavesdropper only observes output of encoder 1 and 2, respectively, while in case 2, the eavesdropper observes outputs of both encoder 1 and 2. The Markov chain X - Y - (Z, E) holds in all cases. The equivocation is measured by the normalized entropy of source sequence conditioned on the observation of eavesdropper. We completely characterize the rate-distortion-equivocation regions for all three cases, and show that layered coding is optimal. Finally, a binary source example is given.

We consider a secure source coding problem with side informations at the decoder and the eavesdropper. The encoder has a source that it wishes to describe with limited distortion through a rate-limited link to a legitimate decoder. The message sent is also observed by the eavesdropper. The encoder aims to minimize both the distortion incurred by the legitimate decoder; and the information leakage rate at the eavesdropper. When the encoder has access to the side information (S.I.) at the decoder, we characterize the rate-distortion-information leakage rate (R.D.I.) region under a Markov chain assumption and when S.I. at the encoder does not improve the rate-distortion region as compared to the case when S.I. is absent. We then extend our setting to consider the case where the encoder and decoder obtain coded S.I. through a rate-limited helper, and characterize the R.D.I. region for several special cases under logarithmic loss distortion (log-loss). Finally, we consider the case of list or entropy constraints at the decoder and show that the R.D.I. region coincides with R.D.I. region under log-loss.

We consider secure multi-terminal source coding problems in the presence of a public helper. Two main scenarios are studied: 1) source coding with a helper where the coded side information from the helper is eavesdropped by an external eavesdropper, 2) triangular source coding with a helper where the helper is considered as a public terminal. We are interested in how the helper can support the source transmission subject to a constraint on the amount of information leaked due to its public nature. We characterize the tradeoff between transmission rate, incurred distortion, and information leakage rate at the helper/eavesdropper in the form of a rate-distortion-leakage region for various classes of problems.

We consider a problem of constrained multi-stage coding for channels with a rewrite option. It is a natural extension of Weissman's channels with action-dependent states to the multistage coding case where an encoder in each stage observes its own message as well as all previous-stage messages, inputs, and outputs. In addition to decoding all messages at the final stage, the new reconstruction constraint introduced in Sumszyk and Steinberg's information embedding with reversible stegotext is imposed on the problem such that the decoder is required to be able to reconstruct all channel input sequences reliably. The complete characterization of the channel capacity region is given for the two-stage case, while the inner and outer bounds to the capacity regions for the cases of three or more stages are provided. For the two-stage case, a discussion regarding the rate constraint of the message in the second stage is also given in which we can draw a connection to the two-stage coding condition which appears in our previous study on channel with action-dependent state and reversible input.

We consider a problem of coding for channels with action-dependent states available noncausally to the encoder where the decoder is additionally required to be able to decode the channel input reliably. Lower and upper bounds on the channel capacity are derived. It is shown that the capacity is determined if there exists a maximizing joint probability distribution in the upper bound which satisfies the two-stage coding condition, and it, in turn, reveals the formula duality between this problem and that of source coding with common reconstruction and action-dependent side information. We also state two simple coding schemes and the corresponding achievable rates for the cases where the two-stage coding condition is not fulfilled.

We consider a secure lossy source coding problem with the presence of an eavesdropper who has access to the source description. An encoder wants to compress the source in such a way that the intended decoder can reconstruct the source sequence and satisfy a distortion criterion, while revealing only limited knowledge about the source to the eavesdropper. In our system an action sequence is generated based on the source description with some costs to influence the side information available to the legitimate decoder and the eavesdropper. We provide a complete characterization of the rate-distortion-cost-equivocation region for a discrete source with correlated action-dependent side information at the decoders. The result serves as a fundamental limit for example in secure sensor networking.

We consider a source coding problem where the encoder can take actions that influence the availability and/or quality of the side information which is available partially and noncausally at the encoder and the decoder. We then characterize the associated achievable tradeoffs between rate, distortion, and cost. In addition, we state and discuss a capacity result for the channel coding dual problem where the formula duality of special cases is recognized.

We determine the rate region of a source coding problem with common reconstruction and action-dependent side information where an action sequence is taken by an encoder over a rate-limited link. We show that the rate region depends only on the sum-rate and the sum-rate distortion and cost function is characterized. The result serves as a fundamental limit in transmission scenarios where the encoder wants to control and monitor the quality of the decoder's reconstruction via the respective uses of action sequences and a common reconstruction constraint.