A generic radio channel emulator to evaluate higher layer protocols in a CDMA system

Currently, we are involved in the standardisation process to specify the next mobile system generation. A wideband code division multiple access (WCDMA) system is considered in most of the region versions. It would be very useful to count on a radio channel emulator which allows one to evaluate higher layers protocols within this context. This paper presents a radio channel emulator developed for a code division multiple access (CDMA) based system. Its versatility and low complexity have been exposed, and the validation process to check the model accuracy has also been shown for this system as an example.Peer ReviewedPostprint (published version

A radio channel emulator for WCDMA, based on the hidden Markov model (HMM)

One of the main development and research subjects within the telecommunications area activity is the 3G mobile systems standardisation. The radio access is, of course, the main trouble in mobile systems, so it is important to investigate its implication. This paper describes a radio channel emulator for the UTRA-FDD made, based on the hidden Markov model (HMM). Since a statistical system behaviour is needed to train the HMM, off-line simulations have been made. The results between simulated and emulated statistics are presented. The use of emulation models implies a loss of accuracy with respect to simulation models, but is adequate to operate in real time. Certainly, the main advantage of using HMM in the emulator is the huge reduction in time, resources and effort with regard to a real simulation of the system. The emulator will allow in future works, for fast testing and comparison of several higher layer protocols and error control schemes.Peer ReviewedPostprint (published version

DVB-T signal detection for indoor environments in low-SNR regime

The problem of coexistence between the primary (licensed) and secondary (non-licensed) users can be solved in various ways. One of them assumes the application of the detailed Radio Environment Maps being a kind of database, where some crucial information about the licensed transmission can be stored. In this paper we propose the new methods for signal detection in low signal-to-noise regime and compare it through hardware experiment with other known techniques used for spectrum sensing.Peer ReviewedPostprint (author’s final draft

Emulador de canales radio para sistemas de comunicaciones móviles

Peer ReviewedPostprint (published version

Implementation of cognitive radio networks to evaluate spectrum management strategies in real-time

This paper illustrates a Universal Software Radio Peripheral (USRP)-based real-time testbed that is able to evaluate different spectrum management solutions that exploit the Cognitive Radio (CR) paradigm. The main objective of this testbed is to provide an accurate and realistic platform by which the performance of innovative spectrum management solutions for a wide set of scenarios and use cases in the context of Opportunistic Networks (ONs) and Cognitive Radio Networks (CRNs) can be entirely validated and assessed before their implementation in real systems. Real-time platforms are essential to carry out significant studies and to accurately assess the performance of innovative solutions before their implementation in the real world. This work provides a comprehensive description of the testbed, highlighting many interesting implementation details and illustrating its applicability for different studies that rely on the CR paradigm. Then, a particular application in a realistic Digital Home (DH) scenario is also illustrated, which allows demonstrating the effectiveness of the real-time testbed and assessing its practicality in terms of user-perceived end-to-end Quality of Experience (QoE) in a realistic environment.Peer ReviewedPostprint (author's final draft

DVB-T channels power measurements in indoor/outdoor cases

In this paper the analysis of the spectrum occupancy in the TV band is provided based on the indoor and outdoor measurements campaigns carried out in Poznan, Poland, and Barcelona, Spain, in 2013. The goal of this work is to discuss the stability and other important features of the observed spectrum occupancy in the context of indoor/outdoor Radio Environment Maps database deployment. Reliable deployment of these databases seems to be one of the critical points in practical utilization of the TV White Spaces for cognitive purposes inside buildings and in densely populated cities.Postprint (published version

On the impact of the user terminal velocity on HSPA performance in MBMS multicast mode

Multimedia Broadcast/Multicast Services (MBMS), introduced in Universal Mobile Telecommunication System (UMTS), have the aim to allow transmissions from a single source entity to multiple destinations. From the radio perspective, MBMS foresees both pointto- point (PtP) and point-to-multipoint (PtM) transmission mode, supported by Dedicated, Common, and Shared channels. The High Speed Downlink Packet Access (HSDPA), analyzed in this paper, can guarantee a higher data rate through the introduction of High Speed Downlink Shared Channel (HS-DSCH), thus improving the performance of MBMS transmissions. The aim of this paper is to investigate the impact of the User Equipment (UE) speed on the maximum number of users that the HS-DSCH can support for MBMS applications. In particular, two different mobility profiles are taken into account (Pedestrian and Vehicular) and the obtained results are validated by considering different transmission power levels, cell coverage sizes and bit rates.Postprint (published version

On the optimization of power assignment to support multicast applications in HAP-based systems

The goal of this research work is to investigate how efficient High Altitude Platforms (HAPs) can be in supporting Multimedia Broadcast/Multicast Service (MBMS) in scenarios in which the terrestrial coverage is not available. Specifically, we propose to implement an effective Radio Resources Management (RRM) policy into the HAP Radio Network Controller (H-RNC), whose main aim is to increase the overall system capacity. The proposed technique achieves its goal by dynamically selecting the most efficient multicast transport channel in terms of power consumption, chosen amongst Dedicated Channel (DCH), Forward Access Channel (FACH), and High Speed Downlink Shared Channel (HS-DSCH). Advantages deriving from the joint use of channels belonging to different categories are exploited. Results achieved when using the proposed RRM are quite manifest and witnesses to the necessity of providing such a feature when deploying integrated HAP/Terrestrial platforms supporting MBMS services.Peer ReviewedPostprint (published version

Evaluation of a multi-cell and multi-tenant capacity sharing solution under heterogeneous traffic distributions

One of the key features of the 5G architecture is network slicing, which allows the simultaneous support of diverse service types with heterogeneous requirements over a common network infrastructure. In order to support this feature in the Radio Access Network (RAN), it is required to have capacity sharing mechanisms that distribute the available capacity in each cell among the existing RAN slices while satisfying their requirements and efficiently using the available resources. Deep Reinforcement Learning (DRL) techniques are good candidates to deal with the complexity of capacity sharing in multi-cell scenarios where the traffic in the different cells can be heterogeneously distributed in the time and space domains. In this paper, a multi-agent reinforcement learning-based solution for capacity sharing in multi-cell scenarios is discussed and assessed under heterogeneous traffic conditions. Results show the capability of the solution to satisfy the requirements of the RAN slices while using the resources in the different cells efficiently.This work has been supported by the Spanish Research Council and FEDER funds under SONAR 5G grant (ref.TEC2017-82651-R), by the European Commission’s Horizon 2020 5G-CLARITY project under grant agreement 871428 and by the Secretariat for Universities and Research of the Ministry of Business and Knowledge of the Government of Catalonia under grant 2020FI_B2 00075.Peer ReviewedPostprint (author's final draft

A novel approach for dynamic capacity sharing in multi-tenant scenarios

Network slicing is included as a key feature of the 5G architecture in order to simultaneously support diverse service types with heterogeneous requirements. The realization of network slicing in the Radio Access Network (RAN) needs mechanisms that allow the distribution of the available capacity in the system in an efficient manner while satisfying the requirements of the different services. In this paper, a capacity sharing function is proposed, which is approached as a multi agent reinforcement learning based on the Deep Reinforcement Learning (DRL) algorithm Deep Q-Network (DQN). The proposed algorithm provides the capacity to be assigned to each RAN slice. Performance assessment reveals the promising behavior of the proposed solution.This work has been supported by the Spanish Research Council and FEDER funds under SONAR 5G grant (ref. TEC2017-82651-R), by the European Commission’s Horizon 2020 research and innovation program under grant agreement #871428, 5G-CLARITY project, and by the Secretariat for Universities and Research of the Ministry of Business and Knowledge of the Government of Catalonia under grant 2019FI_B1 00102.Peer ReviewedPostprint (author's final draft