The open, virtualized, and disaggregated nature of Open Radio Access Network (O-RAN) designs has brought new security issues to mobile networks. Strong and flexible security measures are required in response to these issues, and the integration with existing IT security tools such as Security Information and Event Management (SIEM) systems may represent a viable solution. The method for combining SIEM with O-RAN is presented in this study in order to improve security threat detection and mitigation in mobile and IT settings. In order to improve real-time anomaly detection and reaction, the proposed system will design a specific xApp that acts as an agent to pass events from mobile networks to the SIEM. This would address threats like jamming and Distributed Denial of Service (DDoS) assaults. In addition to improving Intrusion Detection Systems' (IDS) capabilities, SIEM integration with O-RAN offers a dynamic and intelligent security architecture that can react quickly to threats that are always changing in both IT and mobile infrastructures. This study shows how O-RAN and SIEM technology can be combined to protect next-generation mobile networks against advanced cyberattacks.

Urban Air Mobility (UAM) represents an innovative mobility solution designed to alleviate the traffic congestion associated with conventional two-dimensional transportation, which has already saturated both urban and underground spaces. The development of unmanned aerial vehicles (UAVs) and electric vertical takeoff and landing (eVTOL) aircraft is a key enabler for this new, sustainable mode of transporting goods and passengers. To ensure safe operation—especially as these vehicles advance toward autonomous capabilities—and to maintain connectivity for passengers, UAM requires high data-rate, reliable, and low-latency communications. Within the 6G framework, several architectural solutions have been proposed, incorporating components such as terrestrial stations, satellites, and UAVs. In this paper, we propose a two-tier architecture: an aerial tier that leverages multi-hop THz communications among UAM vehicles as backhaul links, and a terrestrial tier comprising conventional cellular base stations (BSs) along with a number of enhanced base stations (eBSs) equipped with high-elevation antenna systems to provide aerial coverage for UAM vehicles (UVs). We will show that our approach ensures reliable UAM connectivity even in high-density urban airspaces, striking an optimal balance between the required number of eBSs and the airborne THz backhauling.

Ensuring seamless connectivity for first responders represents a critical issue in emergency scenarios, where disrupted infrastructures and network congestion can significantly hinder the communication. Open Radio Access Network (O-RAN) promises a level of openness in Radio Access Networks (RANs) that could be advantageous under such critical conditions, allowing for enhanced integration across different operators’ networks to mitigate resource scarcity. This paper introduces an architectural solution based on O-RAN that leverages neutral hosting to provide a unified gateway to RAN infrastructures. Our approach facilitates seamless access for emergency responders and optimizes the allocation of resources at both the RAN and Core levels within a specified area by exploiting the deployment of near-real-time Applications (xApps) and non-real-time Applications (rApps) managed by the neutral host. The results demonstrate the effectiveness of O-RAN neutral hosting in enhancing first responders’ connectivity, showcasing significant improvements in throughput and latency, especially under disaster scenarios. • O-RAN Neutral Hosting is a feasible solution for emergency operator connectivity. • First responders seamlessly communicate through efficient radio resource allocation. • O-RAN Neutral Hosting outperforms traditional RAN before and after the disaster. • Slice isolation strategy further amplifies the advantages of O-RAN Neutral Hosting.

The rapidly evolving landscape of cyber threats poses significant challenges to network security, particularly in decentralized environments, such as edge computing. This article proposes an enhanced intrusion detection system (IDS) architecture that integrates transfer learning (TL) to create a unified supermodel, enabling adaptability and scalability for detecting emerging threats across diverse datasets (DS). The key contributions of this study include: 1) leveraging bidirectional encoder representations from transformer (BERT)-based feature extraction to enhance the semantic understanding of intrusion patterns; 2) employing an multilayer perceptron (MLP) classifier refined through TL to improve classification performance; 3) addressing class imbalance using synthetic minority over-sampling technique (SMOTE); and 4) optimizing model deployment by distributing the heaviest computational tasks for the creation of the unified supermodel across the edge nodes with the available capacity, thereby reducing latency and enabling accurate real-time threat detection by resource constrained IoT devices. The proposed TL-enabled supermodel is periodically updated and shared with the IoT devices, ensuring robust and adaptive security mechanisms without the need for extensive local training. Our experimental evaluation on CIC-IDS 2017 and NSL-KDD 2009 DS demonstrates the effectiveness of the approach, achieving 99% accuracy, precision, recall, and F1-score. Our results highlight the scalability, efficiency, and real-world applicability of our IDS framework, reinforcing its role in fortifying network security within highly dynamic cyber threat landscapes.

5G networks are designed to support both high data rate eMBB services, and low-latency high-reliability URLLC services. Multiplexing these two services on the same wireless frequency band leads to a challenging radio resource allocation problem due to their heterogeneous requirements. Usually, multiplexing is based on the puncturing mechanism by URLLC traffic at the expense of the eMBB throughput’s reduction. In this paper, we investigate the potential of cell-free massive MIMO to multiplex URLLC and eMBB traffic by exploiting the sole spatial diversity through network slicing. We define a theoretical framework to evaluate the system’s performance, based on closed-form expressions for the spectral efficiency and the throughput of eMBB and URLLC services in this new asset. We show that by design the cell-free massive MIMO architecture can support such heterogeneous services without relying on sophisticated interference management techniques or pilot assignment schemes, while guaranteeing their specific QoS requirements.

The OPTIMIST project is positioned into one of the most challenging and societal impactful innovation paths, by contributing to the design and implementation of a Multi-access Edge Computing-empowered service platform enabling the optimized delivery of the most popular type of traffic in the forthcoming 5G networks: mobile video. Advanced prediction tools (e.g. data analytics), MEC-enabled service provisioning, 5G networking, QoE-driven and model-based service optimization using stochastic modeling and algorithmic optimization, are major components toward a holistic system that combines analytical tools and close-to-market technologies. In addition, despite the considerable amount of valuable academic research conducted in the area of MEC- enabled service provisioning, the vast majority of obtained results remains hardly compatible (in terms of system models and implementation platforms) and are often limited to the scope of academic research with no envisaged market transfer plans. OPTIMIST fosters fruitful collaboration of academia and industry targeting at developing an innovative platform for fully personalized delivery of 5G mobile video content.

The 60 GHz band plays an important role for wireless signalling with extremely high data rates, both for WiFi and cellular applications. For the design and performance analysis of this band, the impact of human interactions on the propagation from transmitter to receiver has to be taken into account. While the impact of a single human body blocking the line-of-sight (LOS) has been investigated as a deterministic effect, statistical models describing the effect of multiple human bodies, acting as reflectors, on received power and delay spread are still lacking. To close this gap, this paper analyzes measurements of 60 GHz channel impulse responses in static but “evolutionary” office scenarios that involve one and two people and uses them to calibrate a ray tracer that allows the generation of a larger number of channel realizations. Regression fits are applied to the resulting channel responses to obtain an accurate characterization of human-induced power and delay variations in proximity situations where humans give rise to additional multipath11The work of B. Abou Ali Modad and A.F. Molsich was supported in part by the National Science Foundation and the National Institute of Standards and Technology..

Network and computing infrastructures are nowadays challenged to meet the increasingly stringent requirements of novel applications. One of the most critical aspect is optimizing the latency perceived by the end-user accessing the services. New network architectures offer a natural framework for the efficient orchestration of microservices. However, how to incorporate accurate latency metrics into orchestration decisions still represents an open challenge.In this work we propose a novel architectural approach to perform scheduling operations in Kubernetes environment. Existing approaches proposed the collection of network metrics, e.g. latency between nodes in the cluster, via purposely-built external measurement services deployed in the cluster. Compared to other approaches the proposed one: (i) collects performance metrics at the application layer instead of network layer; (ii) relies on latency measurements performed inside the service of interest instead of utilizing external measurement services; (iii) takes scheduling decisions based on effective end-user perceived latency instead of considering the latency between cluster nodes.We show the effectiveness of our approach by adopting an iterative discovery strategy able to dynamically determine which node operates with the lowest latency for the Kubernetes pod placement.

Wireless Sensor Networks (WSNs) are nowadays used in a variety of applications, to monitor relevant quantities often in large and harsh environments, thanks to their flexibility and versatility. Unfortunately, the nature of the wireless communication channel exposes WSN nodes to security risks. Conventional security countermeasures cannot be applied to the WSN nodes due their resource limitations. In this paper, we propose a lightweight blockchain approach to contrast the physical or logical tampering of WSN nodes. We validate our approach through experiments showing the performance impact and the storage footprint due to the use of the proposed blockchain anti-tampering technique. The proposed approach appears to be suitable in the context of WSNs, although the overhead generated by the blockchain depends on the number of nodes in the WSN.

Softwarization of mobile and optical networks facilitates the inter-working between control planes of the two domains, allowing a more efficient management of available resources. Radio resource utilization benefits from the centralization of mobile network functionalities with the application of high-order functional split options by fronthauling. However, higher-order options require larger bandwidth and lower latency in the fronthaul. Advanced mechanisms for the joint control of the access network represent the sole solution to support such fronthaul requirements. This paper proposes a new cooperation scheme to manage the adaptive flexible functional split in 5G networks conditioned to the resource availability in the optical access network. Results show that the proposed converged approach guarantees the optimal allocation of optical resources through a software defined wavelength and bandwidth allocation. The proposed scheme adapts to current traffic demand and simultaneously allows the mobile network to take advantage of the highest possible centralization of mobile network functions by leveraging flexible functional split adaptively compliant to the current optical traffic demand.

The Safe Cooperating Cyber-Physical Systems using Wireless Communication (SafeCop) project addresses safety-related issues in cooperating cyber-physical systems. These systems, characterised by wireless communications, multiple stakeholders, and variable operating environments, are called Cooperative Open Cyber-Physical Systems (CO-CPS). CO-CPSs can successfully address several societal challenges -- cooperative vehicles have been shown to reduce fuel consumption as well as the number of accidents. A vehicle-to-infrastructure (V2I) cooperation for the traffic management scenario is therefore considered as a key use cases of SafeCop. In this paper, we outline the V2I traffic management scenario, assess the research goals that arise from it, and provide an overview of the architecture of the demonstrator, as well as a roadmap for its development and evaluation.

By providing reliable high-capacity wireless links, the 60 GHz mmWaves band is expected to revolutionize the future wireless multimedia and home entertainment usage model, which is an inseparable part of the 5G concept. Besides the efforts within the frameworks of established standards, such as 802.15.3.c and 802.11ad, there is still lack of experimental measurements and performance evaluations in those environments that closely correspond to the different envisaged realistic application scenarios. Also, the potential of different transmission technologies at this band, besides the OFDM and SC-FDE, which are defined by the above mentioned standards, is not largely investigated in the literature. In this paper, based on UWB experimental channel impulse responses recorded in a modern residential environment, we evaluate the performance of Rake receivers to achieve high data rates (HDRs) with reasonable SNR, but still low Rake's complexity, with the purpose of meeting the QoS requirements of the wireless home entertainment use case. The bit-error rate performance evaluation of both partial and selective Rakes is applied to QPSK, 16-QAM and 64-QAM modulation schemes, defined in the existing standards. The promising results obtained in this study place the Rake receiver architecture as a valuable candidate for future 60 GHz WPANs and WLANs transceivers.

Millimeter-waves radio technology is attracting great interest because large portions of radio spectrum are available from about 30 to beyond 90 GHz to support modern bandwidth- hungry applications with QoS requirements. Fifth generation of mobile communications is mainly envisaged in the spectrum around 28-40 GHz, whereas 60 GHz band is mostly used for indoor wireless local area networks (WLANs). However, with 7 GHz of available bandwidth, 60 GHz links could play a key role for outdoor backhaul, street lamps hot-spots and video surveillance. Studies of 60 GHz outdoor channels are currently limited. Outdoor channels are usually sparser than indoor channels, but the presence of scatterers like, e.g., cars, in the proximity of the link may induce specific patterns in the multipath composition. In this paper, we provide a statistical analysis of the effect of scatterers with large electromagnetic surface, namely cars, on multipath propagation of 60 GHz ultra- wideband (UWB) signals. The analysis is based on experimental data collected in two parking areas with and without parked cars, where a 60 GHz UWB radio transmits from street lamps towards collector points located in the proximity of a building. The measurements were done at eight carrier frequencies in the region 54-66 GHz, using a tunable sliding correlator, thus results also show the channel behavior vs. frequency.

Multi-gigabit 60 GHz radios are expected to match QoS requirements of modern multimedia applications. Several published standards were defined based on performance evaluations over standard channel models. Unfortunately, those models, and most models available in the literature, do not take into account the behavior of 60 GHz channels at different carrier frequencies, thus no guidelines are provided for the selection of the best suitable frequency band for a given service. This paper analyzes the impact of changes in multipath profiles, due to both frequency and distance, on the BER performance achieved by IEEE 802.11ad 60 GHz radios. Our analysis is based on real experimental channel impulse responses recorded through an indoor measurement campaign in seven sub-bands from 54 to 65 GHz with a break at 60 GHz at distances from 1 to 5 m. The small-scale fading is modeled by Rician distributions with K-factors extracted from experimental data, which are shown to give good agreement with the empirical distributions. A strong dependence of performance on both frequency and distance due to the sole multipath is observed, which calls for an appropriate selection of the best suitable frequency band according to the service required by the current session over the 802.11ad link.

Measurements of the 60 GHz ultra-wideband (UWB) indoor channel done in a modern office building at the University of L'Aquila, Italy, are presented. The UWB channel sounder is based on a PN-sequence correlation technique with a pulse width of 0.8 ns. Signals are recorded in different locations in line-of-sight and non-line-of-sight scenarios, and for each location the receiver is moved over a grid of 9 × 9 positions, in order to characterize both the large and the small scale behaviors. Samples of the channel impulse response are recorded at six different carrier frequencies spanning the bands from 54 to 59 GHz and from 61 to 64 GHz, allowing investigations on the dependence of channel parameters on frequency. In this paper, based on these experimental data, we analyze the behavior of the path loss and delay spread of these UWB 60-GHz signals as a function of frequency.

This paper describes a measurement campaign performed in a modern building at the University of L'Aquila, Italy. Measurements are taken for two large bands around 60 GHz, i.e. 54-59 and 61-66 GHz. The channel probe is an ultrawideband (UWB) PN-sequence signal having a bandwidth of 1.2 GHz, which is up-converted to the 60 GHz band and finely tuned in order to span the whole mentioned bands. Measurements were done at several different locations, in line-of-sight and non-line-of-sight scenarios and using different combinations of transmitting and receiving antennas: either omnidirectional or directional antennas with a beam width of 30 or 9 degrees, respectively. Accurate processing of recorded signals and subsequent regression fits allow us to derive path loss models that include both distance and frequency dependence of the power decay. The path loss is modeled as the product of a distance dependent term and a frequency dependent term, both modeled through power laws. Our analysis shows that the parameters of the path loss models for 60 GHz channels in modern buildings assume values comparable to UWB channels.

This paper presents a project that has been recently funded by means of the ERC Starting Grant (http://erc.europa.eu/). The main goal of the project is to develop a new generarion of wireless sensor networks infrastructure to support innovative services for ubiquitous sensing and video. The work is in a very preliminary phase so the paper presents a general overview and the main challenges.

We give a sufficient condition that insures that the impulse response of a channel is of minimum phase. The condition is that the energy of the first path be larger than the power spectral density of all subsequent paths. Establishing a lower bound to the first path energy, this condition is more likely to be met if transmitter and receiver are in line-of-sight. Our results show that the Hilbert transform may give unreliable results, if used to extract the channel phase response from frequency-resolved amplitude measurements when the first path is strongly attenuated.

Ultra-wideband (UWB) wireless technology is envisaged to play a key role in B3G wireless systems, guaranteeing very high bit rates, low power consumption, low costs and location capabilities. The availability of low cost and efficient devices makes UWB technology very competitive on the communications market. However, its worldwide acceptance mainly relies on coexistence issues because of the necessity of sharing the spectrum with other radio systems. The reduction, due to coexistence constraints, in the capacity of an UWB system in a realistic multipath channel is investigated. Link performance of an UWB system that exploits either partial or selective Rake combining at the receiver is evaluated over experimental impulse responses of an UWB indoor channel in an office building. Using these results, system performances are evaluated through a semi-analytical procedure in terms of outage probability and system capacity. Results on system capacity account for the limitations imposed by the current regulation, leading us to introduce the concept of ‘UWB systems limited by coexistence’.

One of the major issues for the design of ultra-wideband (UWB) receivers is the need to recover the signal energy dispersed over many multipath components, while keeping the receiver complexity low. To this aim we consider two schemes for reduced-complexity UWB Rake receivers, both of which combine a subset of the available resolved multipath components. The first method, called partial Rake (PRake), combines theirs/ arriving multipath components. The second is known as selective Rake (SRake) and combines the instantaneously strongest multipath components. We evaluate and compare the link performance of these Rake receivers in different UWB channels, whose models are based on extensive propagation measurements. We quantify the effect of the channel characteristics on the receiver performance, analyzing in particular the influence of small-scale fading statistics. We find that for dense channels the performance of the simpler PRake receiver is almost as good as that of the SRake receiver, even for a small number of fingers. In sparse channels, however, the SRake outperforms the PRake significantly. We also show that for a fixed transmitted energy there is an optimum transmission bandwidth

This paper describes a comprehensive statistical model for UWB propagation channels that is valid for a frequency range from 3-10 GHz. It is based on measurements and simulations in the following environments: residential indoor, office indoor, built-up outdoor, industrial indoor, farm environments, and body area networks. The model is independent of the used antennas. It includes the frequency dependence of the pathloss, as well as several generalizations of the Saleh-Valenzuela model, like mixed Poisson times of arrival and delay dependent cluster decay constants. The model can thus be used for realistic performance assessment of UWB systems. It was accepted by the IEEE 802.15.4a working group (WG) as standard model for evaluation of UWB system proposals

Abstract The paper presents the statistical model for the ultra‐wideband (UWB) indoor channel having a bandwidth of 2.4 GHz and a central frequency of 4.78 GHz. The model is based on propagation experiments performed in different rooms on a floor of an office‐laboratory building. Within each room the receiver antenna is automatically moved over a square grid of 25 × 25 locations spaced 2 cm apart. A correlative channel sounding technique is employed; actually the carrier is modulated by a train of short duration (0.4 ns) pulses shaped by a PN‐sequence. After coherently demodulating the detected signals and removing the PN‐sequence modulation, we post‐process the extracted channel impulse responses by best‐fit procedures to set up a statistical tapped delay line model (STDL) of the UWB indoor channel. We characterize the path loss for line‐of‐sight (LOS) and non‐line‐of‐sight (NLOS) conditions by distance‐power laws and the shadowing by lognormal distributions. A clustered structure is observed in the average power‐delay profiles; rays arrive at the receiver in groups, exponentially decaying with different decay constants. The small‐scale effects are modeled by the Gamma distribution since it verifies with a 95%‐confidence interval both the Chi‐Square test and the Kolmogorov–Smirnov test applied to the experimental data. The shape parameters of such Gamma distributions are truncated Gaussian variables spreading in the range from 1 to 3. An implementation of the derived STDL model is finally proposed and a comparison between the simulated and the measured statistics is performed proving the validity of our approach. Copyright © 2005 John Wiley & Sons, Ltd.

An extensive measurement campaign is carried out in a modern office building. The channel is sounded by a carrier at 4.78 GHz modulated by a train of pulses, each having a duration of 0.4 ns, shaped by a pseudo noise (PN) sequence, covering the band 3.6-6 GHz. The transmitter is moved in six different positions on the floor, while the receiver is moved within each room by a digitally controlled positioner in 625 different locations arranged in a square grid of 25 /spl times/ 25 points with 2 cm spacing. A total of 625 /spl times/ 16 profiles in nonline-of-sight (NLOS) and 625 in line-of-sight (LOS) conditions are recorded within the rooms. LOS measurements are made in the corridor in 11 locations at incremental spacing of 1 m. We describe the measurement technique as well as the procedure by which we process the experimental data to extract the amplitude, phase and delay associated to each path of the channel impulse responses. Finally, we derive LOS and NLOS path-loss models.

We performed a propagation experiment in a modern office building in Rome, Italy. The propagation measurements are based on the use of a vector network analyzer (VNA) over the band 2-12 GHz, with a frequency resolution of 5 MHz. We propose a novel analysis of the dependence of path loss laws on the carrier frequency and bandwidth. Our experimental results show that the path loss exponent strongly depends on the carrier frequency. The path loss exponents increase with the increasing carrier frequency for the line-of-sight (LOS) scenarios, while exhibit an opposite behavior for the non-line-of-sight (NLOS) data. We explain this behavior by the frequency dependence of the reflection coefficient of the walls surrounding the transmitter. Indeed, the lowest frequencies (2-5 GHz) are reflected, while the highest frequencies (up to 12 GHz) pass through the walls.

With the new release of the Federal Communication Commission on matters of regulation of marketing and operation of ultra-wideband (UWB) devices, an analytical framework to enable tractable analysis of the spectrum shape of these signals is needed. We extend the framework introduced by W. A. Gardner to the case of UWB signals. We introduce a generalized UWB signal model that can be specialized to represent the traditional time-hopping (TH) technique as well as the alternative multiple access technique that we indicate as delay coded sequence (DCS). The DCS technique resembles the traditional direct sequence spread spectrum techniques, but it is not based on pulse polarity inversion. The considered matrix signal formulation allows us to easily evaluate the spectral characteristics of UWB signals under many different operating conditions: continuous or discontinuous transmissions, random or periodic scrambling operations, with or without jitter. We evaluate the spectrum of the general UWB signal under the random scrambling assumption, then we specialize it to the TH and DCS cases and discuss the variability of the spectra to some critical design parameters. We obtain an asymptotic expression of the general UWB spectrum that we use to evaluate the UWB interference power at the output of a generic receiver.

Bluetooth is a low-cost, short-range wireless technology capable of providing many communication functionalities, ranging from wire replacement to simple personal area networking. In Bluetooth local networking applications, a critical issue still under study is the evaluation of the network performance when multiple piconets are simultaneously active in the same area, thus, causing mutual interference. We provide a closed-form expression for the packet loss probability in Bluetooth dense piconet area accounting for capture effects due to propagation losses. The effectiveness of the proposed approach is assessed by comparing the analytical results with those obtained from Monte Carlo simulations. By considering different scenarios, we show the dependence of results on the geometry and on the characteristics of the environment. It is observed that packet loss probability can significantly change with the position of the reference receiver in the area, as well as with the extension of the piconets area as compared with the coverage area of the receiver. We use the packet loss probability to evaluate the upper and the lower bounds of the network aggregate throughput and the average packet transmission time. Due to propagation effects, large variations of these parameters with the position of the reference receiver in the area are evidenced.

We consider an ultra-wide bandwidth system using reduced-complexity RAKE receivers, which are based on either selective (called SRake) or partial (called PRake) combining of a subset of the available resolved multipath components. We investigate the influence of the spreading bandwidth on the system performance using the two considered types of RAKE receivers. We show that, for a fix number of RAKE fingers and a fix transmit power, there is an optimum bandwidth. This optimal bandwidth increases with the number of RAKE fingers, and is higher for an SRake than for a Prake. We also investigate the effects of the fading statistics (Rayleigh or Nakagami) on the optimal spreading bandwidth. We find that the optimal spreading bandwidth is approximately the same for both types of fading, but that the actual performance of an SRake can be better or worse in Rayleigh fading (compared to Nakagami), depending on the spreading bandwidth and the number of fingers.

We evaluate the link performance of an ultra-wide band (UWB) system using reduced-complexity RAKE receivers, which are based on either partial combining (called PRAKE) or selective combining (called SRAKE). The first is suboptimum and combines the first arriving multipath components, while the second combines the strongest multipath components. We use a statistical tapped-delay-line channel model that is based on extensive measurement campaigns, and reflects both small-scale and large-scale variations of the channel. Through semi-analytical evaluations of the bit error probability, we show that the simpler PRAKE receiver is almost as good as the SRAKE even for a small number of fingers. We show how this behavior can be related to the channel characteristics.

We provide a closed-form expression for the packet loss probability in Bluetooth networks accounting for capture effects due to propagation losses. The effectiveness of the proposed approach is assessed comparing the analytical results with those obtained from Monte Carlo simulations. By considering different scenarios, we show the dependence of results on the geometry and on the characteristics of the environment. It is observed that packet loss probability can significantly change with the position of the reference receiver in the area, as well as with the extension of the served area as compared with the coverage area of the receiver.

We establish a statistical model for the ultra-wide bandwidth (UWB) indoor channel based on an extensive measurement campaign in a typical modern office building with 2-ns delay resolution. The approach is based on the investigation of the statistical properties of the multipath profiles measured in different rooms over a finely spaced measurement grid. The analysis leads to the formulation of a stochastic tapped-delay-line (STDL) model of the UWB indoor channel. The averaged power delay profile can be well-modeled by a single exponential decay with a statistically distributed decay constant. The small-scale statistics of path energy gains follow Gamma distributions whose parameters m are truncated Gaussian variables with mean values and standard deviations decreasing with delay. The total received energy experiences a lognormal shadowing around the mean energy given by the path-loss power law. We also find that the correlation between multipath components is negligible. Finally, we propose an implementation of the STDL model and give a comparison between the experimental data and the simulation results.