Transmission Scheme Research Articles

Robust Secure Transmission for Active RIS Enabled Symbiotic Radio Multicast Communications

In this paper, we propose a robust secure transmission scheme for an active reconfigurable intelligent surface (RIS) enabled symbiotic radio (SR) system in the presence of multiple eavesdroppers (Eves). In the considered system, the active RIS is adopted to enable the secure transmission of primary signals from the primary transmitter to multiple primary users in a multicasting manner, and simultaneously achieve its own information delivery to the secondary user by riding over the primary signals. Taking into account the imperfect channel state information (CSI) related with Eves, we formulate the system power consumption minimization problem by optimizing the transmit beamforming and reflection beamforming for the bounded and statistical CSI error models, taking the worst-case SNR constraints and the SNR outage probability constraints at the Eves into considerations, respectively. Specifically, the S-Procedure and the Bernstein-Type Inequality are implemented to approximately transform the worst-case SNR and the SNR outage probability constraints into tractable forms, respectively. After that, the formulated problems can be solved by the proposed alternating optimization (AO) algorithm with the semi-definite relaxation and sequential rank-one constraint relaxation techniques. Numerical results show that the proposed active RIS scheme can reduce up to 27.0% system power consumption compared to the passive RIS.

2313. Population-based Incidence of SARS-CoV-2-associated Hospitalizations across the Age Spectrum in New York City, 2020-2021

Abstract Background Population-based incidence rates for hospitalizations due to SARS-CoV-2 can provide an increased understanding of the impact of transmission and mitigation strategies over time, yet there are relatively few estimates of such rates. Thus, we conducted a population-based, surveillance study to estimate incidence rates of SARS-CoV-2 hospitalizations among patients across the age spectrum. Methods From March 2020 to December 2021, we retrospectively reviewed the electronic medical records of patients admitted to an academic, multi-hospital system in New York City (NYC) to determine population-based incidence rates. Eligible patients resided in the pre-defined surveillance area, had ≥2 acute symptoms, and had laboratory-confirmed SARS-CoV-2 infection detected within 14 calendar-days prior to admission to 2 calendar-days after admission. Overall and age group incidence of SARS-CoV-2 hospitalization per 100,000 persons living in the surveillance area were calculated using 2020 census data, adjusted by hospital market share. Results From 2020-2021, 3,283 eligible patients were hospitalized with SARS-CoV-2 at the study hospitals. Patients’ median age in 2020 was 69 years (IQR 56, 80) and in 2021 was 67 years (IQR 51, 79) and 2.5% were 0-17 years old. Overall, 52% were male and 11%, 10%, and 61% were Black, White, and Hispanic, respectively. An estimated 1-4% of adults in age groups >65 years living in the surveillance area were hospitalized (Table). From 2020 to 2021, the overall population-based annual incidence rate and annual incidence rates in age groups 50-64, 65-74, 75-84, and ≥85 years decreased. While not significant, the incidence rate increased in patients 0-14 years. Conclusion These population-based incidence rates provide unique insights into the SARS-CoV-2 burden in a predefined surveillance area in NYC which served as the epicenter of the first U.S. wave of the pandemic. While incidence rates decreased in those >50 years old, rates were largely unchanged in those < 50 years old suggesting that younger adults and children had continued and potentially increased exposures to SARS-CoV-2 and/or lower vaccination rates than older adults during the second full year of the pandemic. Such incidence data can measure the impact of mitigation strategies. Disclosures Lisa Saiman, MD MPH, Merck & Co., Inc,: Grant/Research Support|Merck & Co., Inc,: Member, DSMB|Pfizer, Inc: Member, DSMB Edward E. Walsh, MD, Icosavax: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Grant/Research Support|Merck: Honoraria|Moderna: Advisor/Consultant|Pfizer: Grant/Research Support Angela R. Branche, MD, Cyanvac: Grant/Research Support|GSK: Advisor/Consultant|Janssen: Advisor/Consultant|Merck: Grant/Research Support|Pfizer: Grant/Research Support Julia A. Schillinger, MD, MSc, Merck & Co.: Employee, Stocks and Bonds MATTHEW R. PHILLIPS, MPH, Merck & Co., Inc., Rahway, NJ, USA: Employee|Merck & Co., Inc., Rahway, NJ, USA: Stocks/Bonds Lynn Finelli, DrPH, MS, Merck&Co: Stocks/Bonds

Utilising technology as a transmission strategy in intangible cultural heritage: the case of Cantonese opera performances

ABSTRACT Globalised technological advancements have radically transformed how intangible cultural heritage (ICH) is inherited in contemporary society. Despite being recognised as a Human ICH by the United Nations Educational, Scientific, and Cultural Organisation, Cantonese opera is facing existential crises attributed to an ageing demographic and shrinking audience base. To survive in a rapidly changing sociocultural landscape, Cantonese opera performances in Hong Kong have embraced modern technologies, including artificial intelligence, holographic projection, and virtual reality. By exploring the perspectives of 86 Cantonese opera practitioners, this study critically examines the perceptions, experiences, and challenges associated with technology adoption as a safeguarding strategy for ICH transmission. This study revealed the complex interplay between technology use and cultural transmission, adding to heritage literature by shedding new light on audience reach, content enhancement, value creation, and funding strategies in the context of technology adoption, and the corresponding negotiation of tradition and modernity within ICH communities. The findings emphasise the importance of preserving traditional core values, identity, and artistry inherent in the performing arts of ICH, even as technology adoption becomes radically widespread, shedding light on a cautious integration of technology in ICH in this technology-focussed era.

Design of equalizers for frequency selective MIMO systems with low redundancy

In this paper, we propose several designs of filter bank based decision feedback equalizers (DFE) for frequency selective multi-input multi-output (MIMO) systems. Transmission schemes over frequency selective channels are typically block based, and redundancy in form of guard intervals must be used to avoid inter-block interference (IBI). This paper will focus on the case where spectral efficiency demands low levels of redundancy. Then the remaining IBI will be eliminated by a separate feedback loop. The co-channel interference (CCI) inherited in MIMO channels will be eliminated by different DFE schemes. In another approach, a multi-tap MIMO DFE will be designed to deal with both IBI and CCI. The simulation results show that for quasi-static frequency selective MIMO channels, the multi-tap DFE provides the best performance while for Raleigh frequency selective MIMO channels, the dual loop DFE is a good solution for transmission with low redundancy.

Hybrid backscatter communication for IoT devices in remote areas

The IoT devices placed in remote locations require a battery replacement very often, which is not a convenient option. Backscatter communication can resolve this problem, as backscatter communication is a data transmission in which an RF signal incident from the gateway is used for energy harvesting, and this energy will be employed for data transmission. In this paper, a hybrid contention-based TDMA scheme is proposed, which provides slots to devices by dividing them into groups, and then contention is employed in groups to acquire a slot; if a device is not able to transmit during harvest, then transmit (HTT) period, then it can transmit in variable sub frame and the devices which are not able to completely transmit during HTT period can reserve subframes. The proposed hybrid scheme is compared with the TDMA scheme for average transmission delay.The proposed scheme provides scalability. The difference between the average transmission delay of TDMA and the proposed hybrid scheme is from 6 to 20 s, depending on the number of devices added and when traffic is generated.

Paired-subcarrier equalization for phase noise and transmitter IQ skew in digital subcarrier multiplexing system

The digital subcarrier multiplexing (DSCM) transmission scheme is expected for future ultra-large baud rate transmission. However, the phase noise and transmitter (Tx) IQ skew tolerance are decreased due to the narrow sub-band transmission and conjugated interference from symmetric subcarrier. In this paper, we propose a paired-subcarrier equalization scheme to jointly mitigate the phase noise and Tx IQ skew. We use a phase locking loop (PLL) embedded 4 × 4 MIMO equalizer to simultaneously realize polarization demultiplexing, phase noise and Tx IQ skew compensation. The 4 × 4 MIMO can deal with the paired-subcarrier interference in the DSCM transmission. Besides, since the inner subcarrier suffers smaller interference from its symmetric subcarrier, we estimate the phase noise by inner subcarriers and share the phase noise information with other subcarriers to reduce the overall complexity. Through simulations of 100-GBaud 64-QAM DSCM coherent optical fiber transmission consisting of eight 12.5-Gbaud subcarriers and experiment of 10-GBaud four-subcarriers PM-16QAM transmission, we find that the PLL embedded equalizer for DSCM scheme exhibits better skew and phase noise compensation ability compared with other equalizers. Additionally, we compare the performance of single-carrier and DSCM schemes with the proposed equalizers in simulation. The influence of phase noise and Tx IQ skew on DSCM transmission can be largely relaxed.

Secure transmission of medical images in multi-cloud e-healthcare applications using data hiding scheme

In recent years, medical image transmission using a multi-cloud system has played a significant role in e-Healthcare infrastructure. It allows medical practitioners to easily store, retrieve, and share patients’ medical information across multiple stakeholders. However, multi-cloud image transmission may be vulnerable to multiple security breaches, such as authentication, confidentiality, and security issues. Motivated by these issues, this paper proposes a data-hiding scheme for secure medical image transmission in a multi-cloud environment. The proposed scheme ensures imperceptible robustness and watermark security at a low computational cost. Here, the medical image is divided into a number of shares using Neighbor Mean Interpolation (NMI). To achieve confidentiality, Electronic Patient Healthcare Record (EPHR) is encrypted using Double Scan Pixel Position Shuffling (DSPPS) approach. Then, the encrypted EPHR is divided into shares and embedded in the cover medical image shares. Finally, a minimum of 50% of watermarked image shares are utilized to retrieve the original medical image and encrypted EPHR, consequently reducing multi-cloud latency and computational burden. Experimental results show that the proposed scheme shows high imperceptibility, robustness, and watermark security at a low computational cost. Comparative analysis with some of the recent popular data hiding schemes shows that the proposed scheme has improved imperceptibility and robustness by 10%–15% (approximately) with higher watermark security at a low computational cost.

Network coding construction for a special class of three unicast sessions

For a special class of three unicast sessions, in which the maximum flow from each sender to each receiver is the same positive integer k, a network coding approach is proposed. A multigeneration mixed strategy, in which (2 × n + 1) consecutive generations are taken as a mixed set, is adopted. The precoding strategy is adopted at the senders, random linear network coding technology is adopted at intermediate nodes to transmit data, and interference alignment technology is used at the receivers to eliminate some interference information. The proposed approach can construct a network coding data transmission scheme, in which the transmission rate vector of the senders is [(n + 1) × k/(2 × n + 1), n × k/(2 × n + 1), n × k/(2 × n + 1)]. The feasibility of the proposed approach is mathematically deduced and proven, and the simulation results verify the conclusions of the theoretical analysis.

Guaranteeing Zero Secrecy Outage in Relaying Systems under Eavesdropper’s Arbitrary Location and Unlimited Number of Antennas

This paper proposes a three-phase transmission scheme to ensure zero secrecy outage in decode-and-forward relay systems by using the strategies of artificial noise (AN) injection and channel state information (CSI) leakage avoidance. The zero-outage secrecy spectral efficiency (ZOSSE) and energy efficiency (ZOSEE) of the scheme are then analyzed. Finally, the paper demonstrates that the scheme can always achieve zero secrecy outage even when the eavesdropper has an unlimited number of antennas or is in an arbitrary location, which shows its practical applicability. The paper also shows that the ZOSSE increases with the transmit power and that both the ZOSSE and the ZOSEE are maximized when the relay is halfway between the transmitter and the receiver. This suggests that the placement of the helper node is important in securing the communication of two distant nodes.

NuWa: off-state tolerant backscattering system with uncontrolled excitation traffics

Backscatter communication relies on passive reflections of the existing radio frequency (RF) signals, making it suitable for low-power and low-complexity communication in IoT applications. However, the performance of existing systems severely degrades in real-life environments, due to irregular “on” and “off” states of ambient signals like WiFi, which are not controllable. In this paper, we propose a joint coding and framing scheme for the backscattering physical layer to fight against the off-state in the excitation signal. We first design transmission schemes including both the Reed-Solomon (RS) codes and the frame structure, to correct the burst error caused by the off states. In order to implement the codes at the resource-constrained tag, we design a look-up table for the encoding process. We prototype our system NuWa that could efficiently backscatter with uncontrolled traffics generated randomly. We demonstrate that NuWa could achieve a 1 Mbps transmission throughput when the tag is over 1 m away from the receiver in high traffic load and 150 kbps in low traffic load. Finally, we evaluate the throughput with respect to the distance change between the tag and the receiver, and 950 kbps is achieved at a distance of 6,m.

Reconfigurable-Intelligent-Surface-Aided Number Modulation for Symbiotic Active/Passive Transmission

Reconfigurable intelligent surface (RIS)-aided symbiotic active/passive transmission is a promising communication paradigm, which is able to improve the propagation environment while transmitting additional information. In this paper, a novel scheme, termed RIS-aided number modulation (RIS-NM), is proposed for symbiotic active/passive communications. In RIS-NM, the RIS elements are divided into in-phase (I-) and quadrature (Q-) subsets depending on their phase shift configurations, and the number of elements in the I-subset (or Q-subset, equivalently) is used to convey the RIS’s private information. A low-complexity yet near-optimal detector is designed for RIS-NM by shrinking the search space of constellation points. We then investigate a special case of RIS-NM, termed RIS-aided number shift keying (RIS-NSK), in which the radio-frequency source transmits unmodulated carrier signals. Statistic channel state information (CSI)-based maximum-likelihood (ML) detection is developed for RIS-NSK. We analyze the bit error rate (BER) performance of RIS-NM/NSK over Rician fading channels. BER upper bounds are derived in closed-form for RIS-NM by assuming instantaneous CSI-based ML detection, while an approximate BER expression is obtained for RIS-NSK by assuming statistic CSI-based ML detection. Furthermore, we extend RIS-NM to multiple-input multiple-output scenarios. Our simulation results in terms of BER corroborate the performance analysis and the superiority of RIS-NM over the state-of-the-art RIS-aided symbiotic active/passive transmission scheme.

Reconfigurable-Intelligent-Surface-Aided OTFS: Transmission Scheme and Channel Estimation

In this paper, we study the uplink transmission scheme and channel estimation design for reconfigurable intelligent surfaces (RIS)-aided orthogonal time frequency space (OTFS) systems in high-mobility scenarios. To this end, we first propose an efficient and reliable transmission scheme which utilizes the delay-Doppler information in OTFS to facilitate the configuration of RIS. Specifically, the proposed scheme exploits the estimated delay and Doppler shifts of the cascaded channel to sense the channel parameters, and the sensing parameters are then used for RIS passive beamforming. It is noteworthy that we estimate the channel state information (CSI) by employing only one OTFS frame and configure the RIS based on the predicted channel parameters, leading to substantially reduced channel training overhead and more real-time RIS configuration. To obtain the essential information for channel information sensing, we then propose a low-complexity algorithm which determines the Doppler and delay shifts of the channel between the user and RIS based on linear systems and the mapping relationship of the delay-Doppler pairs, respectively. With the delay-Doppler information in hand, a user localization algorithm constructed by the least square (LS) and a channel tracking method relying on extended Kalman filter (EKF) are then presented to obtain the spatial angle information. By making use of the channel parameters acquired at the base station (BS), the RIS reflection vector is designed to maximize the achievable rate. The results obtained from the simulation experiments affirm the efficacy of the proposed scheme, thereby confirming its capability to attain efficient communications under high Doppler channels.

Age-of-Information-Based Computation Offloading and Transmission Scheduling in Mobile-Edge-Computing-Enabled IoT Networks

The emergence of Mobile Edge Computing (MEC) technology has deployed edge clouds with strong computing capabilities closer to Internet of Thing (IoT) devices, which can effectively meet the demands for computing power and latency. However, in addition to the stringent latency requirements, more and more emerging IoT applications also have higher standards for the freshness and timeliness of collected information. In order to ensure the freshness and high information value in IoT system, we propose an Age of Information (AoI)-based optimization strategy for computation offloading and transmission scheduling. The strategy considers the AoI during the transmission phase and the execution phase, respectively, under the constraints of delay and remaining energy. Then, a joint optimization model is established based on the comprehensive benefits of AoI and computation rate. To address the strong coupling between the offloading decision and the transmission decision, the original optimization problem is divided into two stages. By the use of the Deep Deterministic Policy Gradient (DDPG) algorithm and the Dueling Double Deep Q Network (D3QN) algorithm, the solution is obtained in terms of the offloading decision and transmission scheduling decision, respectively. The proposed joint optimization strategy considers the impact of the transmission decision on the offloading decision and is adaptable to the dynamic changes in the channel connection between the edge cloud and the user due to user mobility. Experimental results show that compared with other offloading and transmission strategies, the proposed approach has higher overall system revenue and lower AoI.

Effect of DC grounding electrode currents on the corrosion interference behavior of cathodic protection of nearby pipelines

When operating a direct current (DC) transmission grounding electrode in single-pole return ground mode, transient currents traverse the soil, generating stray currents. These currents can intensify the corrosion of long-distance transmission pipelines near the grounding electrode, subsequently altering the pipeline’s cathodic protection potential. Previous investigations into the interference of grounding electrodes on pipeline cathodic protection have overlooked the cathodic protection systems themselves. Addressing this gap, we integrated COMSOL’s electrochemical module with its AC/DC module. To corroborate the accuracy of our COMSOL-based models, we devised specific validation experiments. Additionally, we crafted a COMSOL application builder interface to streamline computations. Consequently, we derived a multi-regression function to express the cathodic protection potential of the pipeline under varied factors and executed a regression tree classification for soil resistivity. To pinpoint optimal corrosion protection for pipelines, we simulated the cathodic protection of segmentally isolated pipelines, determining that potential excursions can be notably mitigated. This research offers insights into both disturbance evaluation and protective strategies for DC transmission and pipelines.

An Energy-Efficient Multimode Transmission Scheme for Underwater Sensor Network

Underwater sensor network plays a critical role in the ocean data collection owing to its capability of providing reliable and wide communication coverage. How to assure lifetime performance of the network with limited energy supply has always been a key research issue. In this paper, we propose an underwater acoustic sensor network model which supports data delivery from each underwater sensor node (USN) to sea surface sink node (SN) in either direct or relay-assisted transmission mode, i.e., transmission mode between each USN and the SN can be dynamically selected according to network’s current state. To optimize its lifetime performance, we model the mode selection and resource allocation issue jointly into a non-convex and mixed integer programming problem. In order to efficiently solve it, we further divide the original problem into two subproblems: resource allocation subproblem and joint mode and relay selection subproblem. We prove that the reformulated non-convex resource allocation problem can be equivalent to a convex optimization problem, and its optimal solution can be found by using Lagrange dual decomposition method. For the second subproblem, some critical conditions are analyzed to determine optimal relays with the criterion of balancing energy consumption between USNs and a matching approach is designed to obtain the mode and relay selection results based on USNs’ priorities. Simulation results validate that the proposed transmission scheme is effective and superior to the traditional time division multiple access scheme.

Joint Communication and Sensing Design for Multihop RIS-Aided Communication Systems in Underground Coal Mines

How to achieve reliable communication and safety monitoring is very important in coal mines. However, most of the existing transmission strategies and sensing-based monitoring approaches assume a single objective and neglect Non-Line-of-Sight (NLOS) problems brought by winding tunnels or mine collapses. To this end, we firstly propose a multi-hop reconfigurable intelligent surfaces (RISs) aided joint communication and sensing (JCAS) approach to maximize the energy efficiency of the JCAS access point and the sum sensing rates in order to improve the sensing accuracy. Specifically, we formulate an energy-efficient optimization problem by jointly designing both the phase-shift matrix and the switches status of the RISs as well as the transmit power of the access point. The problem is solved by adopting the successive convex approximation-based alternating optimization algorithm, the second-order optimization method, the Lambert-w function, and the Newton’s method. Moreover, a sensing-based rate optimization problem is also solved via the Lagrange relaxation method and the Gradient descent method. Simulation results demonstrate that the proposed algorithm has better robustness and higher energy efficiency.

Comprehensive Evaluation Model and Methodology for Offshore Wind Farm Collection and Transmission Systems

With the gradual development of offshore wind farms toward large-scale and long-distance trends, economically efficient methods for correcting and transmitting offshore wind energy have garnered increasing attention. The rational and effective evaluation of offshore wind power collection and transmission methods has become an urgent issue. To address this, a comprehensive evaluation model for collection and transmission systems, considering factors such as network losses, lifecycle costs, and reliability, was established. This proposed model was applied to multiple sets of typical collection and transmission scenarios, utilizing an improved TOPSIS comprehensive evaluation method based on dynamic combination weighting to achieve the comprehensive optimization of collection and transmission schemes. Case studies have validated the feasibility of the comprehensive evaluation model. The results indicate that with an increase in offshore distance, the AC/DC collection and transmission system is superior to the all-AC collection and transmission system, and the all-DC collection system exhibits potential cost advantages.

A Single Mutation of VP2 is Responsible for the Lethality and Antigenicity Differences between Novel Variant and Very Virulent IBDV Strains

Infectious bursal disease is an acute, immunosuppressive infectious disease in chickens caused by the infectious bursal disease virus (IBDV), which causes huge economic losses to the global poultry industry. Persistently circulating very virulent IBDV (vvIBDV) and newly emerging novel variant IBDV (nVarIBDV) are the two dominant epidemic strains of IBDV in East Asian countries such as China. Compared to lethal vvIBDV, nonlethal nVarIBDV has more insidious pathogenicity and can partially escape the immune protection of the existing vvIBDV vaccine, suggesting its potential adaptive survival strategy. However, the underlying molecular mechanism remains unknown. The viral capsid protein VP2 is closely related to cell tropism, virulence, and antigenic variation of IBDV. In this study, for the first time, we demonstrated that residue 279 of VP2 is responsible for the difference in pathogenicity between nVarIBDV and vvIBDV and that the D279N substitution reduces the lethality of vvIBDV from 70% to 0%. Moreover, a significant reduction in the viral load and inflammatory factor levels in the immune organs and blood of infected chickens may be important mechanisms for reducing the lethality of IBDV. Additionally, residue 279 was an important molecular basis for the antigenic differences between nVarIBDV and vvIBDV. D279N substitution reduced the neutralizing ability of vvIBDV antiserum against nVarIBDV by affecting the binding ability of antibodies and antigens. Our results indicate that nVarIBDV has an infection transmission strategy that facilitates its survival by hiding viral pathogenicity and escaping antiserum neutralization, which not only has significant implications for the systemic cognition of viral genetic evolution and pathogenesis but also provides new ideas for the comprehensive prevention and control of IBDV.

Energy Efficiency Optimization for a V2X Network with NOMA-CoMP Enabled

With the increase in user density, it is a challenging problem to achieve higher energy efficiency in vehicle-to-everything (V2X) networks, where frequent handovers occur as users continuously pass through dense cell boundaries. In this paper, we investigate this energy efficiency problem in a highly dense V2X network. To alleviate inter-cell interference and reduce unnecessary handovers, we propose a user-centric network architecture and utilize the coordinated multiple point (CoMP) transmission scheme to enable multiple roadside access points (APs) simultaneously to service one mobile vehicle. Moreover, non-orthogonal multiple access (NOMA) is adopted to enable multiple users to multiplex within one sub-channel and improve system spectrum reuse. Accordingly, the energy efficiency optimization problem is formulated as system achievable rate per joule, with the constraints of the AP transmit power budget, vehicle minimum rate requirements, and the maximum number of CoMP APs serving each vehicle. To solve the optimization problem, a semi-dynamic CoMP AP clustering algorithm is proposed to select a group of CoMP APs to serve a vehicle user by considering the vehicle–AP channel coefficients and the vehicle user’s achievable energy efficiency. Then, with the selected CoMP AP clusters, a bidirectional selection algorithm is applied via NOMA to select multiple vehicle users multiplexing within one sub-channel and perform sub-channel power allocation. Numerical simulations are presented to verify the effectiveness of the proposed algorithms, and the results show the improvements offered by the proposed algorithms compared to current benchmarks.

Smoothing of Binary Codes, Uniform Distributions, and Applications.

The action of a noise operator on a code transforms it into a distribution on the respective space. Some common examples from information theory include Bernoulli noise acting on a code in the Hamming space and Gaussian noise acting on a lattice in the Euclidean space. We aim to characterize the cases when the output distribution is close to the uniform distribution on the space, as measured by the Rényi divergence of order α∈(1,∞]. A version of this question is known as the channel resolvability problem in information theory, and it has implications for security guarantees in wiretap channels, error correction, discrepancy, worst-to-average case complexity reductions, and many other problems. Our work quantifies the requirements for asymptotic uniformity (perfect smoothing) and identifies explicit code families that achieve it under the action of the Bernoulli and ball noise operators on the code. We derive expressions for the minimum rate of codes required to attain asymptotically perfect smoothing. In proving our results, we leverage recent results from harmonic analysis of functions on the Hamming space. Another result pertains to the use of code families in Wyner's transmission scheme on the binary wiretap channel. We identify explicit families that guarantee strong secrecy when applied in this scheme, showing that nested Reed-Muller codes can transmit messages reliably and securely over a binary symmetric wiretap channel with a positive rate. Finally, we establish a connection between smoothing and error correction in the binary symmetric channel.