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This paper analyses the possibility to exploit opportunistic spectrum access (OSA) for short-range radio communication systems within indoor locations in dense urban areas. In particular, considering the service area of a primary system devoted to providing outdoor coverage in a dense urban scenario, the percentage of indoor locations where the secondary users can reuse the primary frequency band without disturbing the primary system or being disturbed is estimated. The analysis considers heterogeneous path loss models for the primary and secondary systems encompassing the characterization of outdoor, indoor and building penetration losses. Obtained results quantify how aspects like the location of the primary network elements and the considered interference margins to protect primary transmissions impact on the spatial availability of the primary band within the interior of the buildings., Postprint (published version)

The benefits of jointly managing the combined radio resources offered by heterogeneous networks consisting of several Radio Access Technologies (RATs) have been profusely studied and assessed in recent years. Nevertheless, most of the existing work assumes scenarios where all RATs are accessible (provided the RAT is not at full capacity) to all users demanding service. If this is so, the obtained benefits become rather optimistic given that we neglect the fact that the deployed RATs may have different coverage overlapping conditions among them and that users may not have terminals that support all RATs (i.e. multimode terminals). In this paper we extend a previously developed Markov framework in order to capture the effect of having different coverage overlapping conditions along with the capability of certain terminals to support all or a subset of available RATs. As a result, we assess the degradation, in terms of Erlang capacity, that a heterogeneous network undergoes in scenarios with limited terminal and coverage conditions and compare it to the ideal case of full coverage and full terminal availability., Peer Reviewed, Postprint (published version)

This paper presents the optimum user allocation in heterogeneous scenarios with CDMA and TDMA technologies in order to minimize the total outage probability in the uplink. An analytical model reflecting the different nature of the two access technologies is presented in order to formulate the optimization procedure. It is shown how the optimum allocation depends on the specific parameters of the two technologies, as illustrated with some representative results. The proposed optimization methodology is claimed to have applicability in the field of Common Radio Resource Management strategies for Beyond 3G networks., Peer Reviewed

This paper addresses the problematic of congestion control in the radio access interface when considering the allocation of voice and data services over several Radio Access Technologies (RATs). In particular, the GSMIEDGE Radio Access Network (GERAN) and the UMTS Terrestrial Radio Access Network (UTRAN) are considered for the evaluation of congestion control strategies. After a congestion situation in the radio access is detected, congestion resolution mechanisms are triggered in order to reduce the overload in the congested RAT(s). In this paper, a framework for the detection and resolution of congestion conditions in a multi-access network is presented. Moreover, three approaches intending to solve congestion situations are proposed and the evaluation of an inter-RAT handover algorithm for solving congestion events in GERAN is also presented., Peer Reviewed, Postprint (published version)

In order to support the conceptual development of Common Radio Resource Management (CRRM) algorithms, this paper provides an analytical approach to the performance evaluation of Radio Access Technology (RAT) selection procedures in a multi-RAT/multiservice environment. In particular, a 4-Dimensional (4D) Markovian model is devised so as to consider the allocation of voice and data services in a GERAN/UTRAN system. Through the analytical definition of well-established Key Performance Indicators (KPIs) we provide numerical results on the evaluation of a load balancing RAT allocation policy., Peer Reviewed, Postprint (published version)

Beyond 3G (B3G) networks will encompass, among other features, a wide range of radio access technologies (RATs) providing users with a flexible and efficient access to the increasing pool of demanding services. This will allow users to get connected using the access technology that is most suitable according to some specified criteria. Consequently, to take full advantage of B3G networks, mobile terminals will need to support a larger set of capabilities. Among those, the support of different RATs, i.e. multi-mode capacity, is a must. This paper addresses the impact of multi-mode terminals in an EDGE/UMTS heterogeneous network with multi-service provisioning. Results indicate that multi-mode terminal availability should be considered when designing common radio resource management strategies in heterogeneous wireless access networks. Specifically, a service-based initial RAT selection policy is evaluated, revealing different behaviors for different multi-mode terminal availabilities and service-class mixings. In order to compensate the limitations imposed by non-multi-mode terminals, it is suggested to actuate over GERAN by using a resource reservation scheme for interactive users. By doing so, we tradeoff the QoS between multi-service/multi-mode users., Peer Reviewed, Postprint (published version)

This paper analyzes the performance of a MAC scheme for wireless local area networks (WLANs) that makes use of distributed queues to improve radio channel utilization. Analytical values for the maximum throughput performance are derived as a function of the system parameters. The obtained results show that the proposed scheme outperforms the legacy 802.11 MAC protocol in terms of maximum stable throughput. This benefit is obtained from eliminating back-off periods and collisions in data packet transmissions while minimizing the needed control overhead. The proposal also makes performance to be independent of the number of nodes transmitting in the system and provides stability for high load conditions, Peer Reviewed

Este artículo proporciona una visión del problema de la gestión de recursos radio (RRM Radio Resource Management) en el contexto de la evolución de los sistemas de comunicaciones móviles. Se enfatiza la importancia creciente que las técnicas de RRM tienen en este panorama evolutivo. Se aborda el papel jugado en las tecnologías GSM/GPRS (Global System for Mobile Communications / General Packet Radio Service) y se pone especial énfasis en UMTS (Universal Mobile Telecommunications Service), ya que la tecnología W-CDMA (Wideband Code Division Multiple Access) hace que RRM pase a ser una pieza clave para su éxito futuro. Finalmente, se presenta una prospectiva en el marco de las redes móviles heterogéneas., Postprint (published version)

A set of novel PHY-MAC mechanisms based on a cross layer dialogue have been proposed, and their performance has been analyzed. System efficiency improvement is achieved by means of automatic transmission rate adaptation, trading off bit rate for power, with resulting energy saving features in a generic packet-switched CDMA access network. The rate adaptation mechanism improves spectrum efficiency while keeping packet delay minimized. On the other hand, power dependent strategies reduce power consumption and intercell interference. Simulation results show that the benefits obtained are very encouraging, so the proposed schemes could be used in future communication systems., Peer Reviewed

The paper analyses the performance of a novel MAC-PHY scheme for wireless local area networks (WLAN) that makes use of distributed queues and cross-layer concepts to improve radio channel utilisation. Analytical values for the maximum throughput performance are derived as a function of different scenario parameters. The obtained results show that the proposed scheme outperforms throughput bounds achieved when using a legacy 802.11 MAC protocol. The usage of distributed queues and cross-layer information eliminates back-off periods and collisions in data packet transmissions, makes performance to be independent of the number of stations transmitting in the system and provides stability for high load conditions. Furthermore, the cross-layer concept allows the MAC layer to improve its decisions by means of physical layer information knowledge., Peer Reviewed, Postprint (published version)

Third-generation mobile communication systems will bring a wide range of new services with different quality of service requirements and will open the ability to exploit radio resource management functions to guarantee a certain target QoS, to maintain the planned coverage area and to offer a high-capacity while using the radio resources in an efficient way. RRM functions impact the overall system efficiency and the operator infrastructure cost, so they will definitively play an important role in a mature 3G scenario. In order to provide some insight into RRM strategies implementation, a range of rep resentative case studies with several innovative algorithms arc presented and supported by simulation results in a realistic UMTS Terrestrial Radio Access Network scenario as devised in the 3GGP standardization forum. In particular, a decentralized uplink transmission ratc selection algorithm in the short term, a congestion control mechanism to cope with overload situations, and downlink scheduling for layered streaming video packets are proposed., Peer Reviewed

A type II hybrid automatic repeat request scheme is considered as a retransmission strategy in a direct-sequence code-division multiple-access packet mobile radio network. An analysis based on equilibrium point analysis is presented to model the behavior of the system in a message-based traffic generation model. A simulation approach is introduced to validate the proposed analytical model, obtaining results that closely match those derived theoretically., Peer Reviewed

En este libro se presentan los aspectos fundamentales que intervienen en los sistemas de comunicaciones móviles, al objeto de facilitar la comprensión de los principios de funcionamiento y los requerimientos tanto actuales como futuros de dichos sistemas. Se hace hincapié en el componente conceptual y se intenta evitar en lo posible los desarrollos matemáticos. Con ello se pretende que los temas tratados permitan al lector una mejor asimilación de los mecanismos que intervienen en los sistemas de comunicaciones móviles. El texto se acompaña de ejemplos de aplicación sobre sistemas como GSM, DECT, Bluetooth, WLAN o UMTS, que ayudan a afianzar los conceptos expuestos y a conocer algunos parámetros concretos de diseño. Se asume que el lector tiene conocimientos previos de probabilidad y fundamentos de comunicaciones digitales.

The presence of different service classes in the context of 3G mobile communication systems opens up new possibilities to exploit the spectrum in an efficient way. In the search of such a high efficiency, radio network congestion may arise and it is mandatory to include suitable algorithms to deal with these situations. Here, congestion control mechanisms in the radio interface of UTRA FDD are proposed and analysed. Results show that under congestion it seems more suitable to adopt firm and strict rate control decisions rather than softer policies., Peer Reviewed, Postprint (published version)

W-CDMA performance is tightly coupled to the amount of interference in the air interface and eventually depends on many strongly interrelated system parameters that need to be suitably managed through radio resource management (RRM) strategies in order to achieve a high efficiency. Interference characterisation in terms of average and standard deviation, which are suitable for radio network planning, may not suffice for a proper RRM design because of its inherently dynamic nature. The time correlation of the interference and the main system level parameters affecting its dynamics are raised: shadow fading, mobile speed, traffic characteristics and cell load., Peer Reviewed, Postprint (published version)

En la presente tesis doctoral se ha realizado una serie de aportaciones para contribuir al desarrollo de los sistemas de comunicaciones móviles de tercera generación. Esta nueva generación de sistemas utilizará una técnica de acceso del tipo CDMA y pretende poder garantizar una cierta calidad de transmisión en las comunicaciones. En este sentido, esta tesis presenta nuevas propuestas tanto para el protocolo de acceso al medio (MAC) como para los algoritmos de gestión de los recursos radio (RRM). Las propuestas han sido presentadas, estudiadas y analizadas en diferentes entornos representativos de trabajo y se ha demostrado su validez para su utilización en un sistema real de comunicaciones. Además, por su sencillez de implementación y alta eficiencia en la utilización de los recursos, se ha comprobado que todas ellas son candidatas muy adecuadas para poder formar parte de los estándares en formación para los citados sistemas. Glosando los aspectos desarrollados en la presente tesis doctoral, cabe destacar los siguientes puntos: ? Se han estudiado en profundidad las necesidades y requerimientos del interfaz radio en los sistemas de comunicaciones móviles de tercera generación, centrando el estudio en las transmisiones en modo paquete para entornos con acceso CDMA. ? Se ha propuesto un nuevo protocolo MAC para trabajar en este entorno de operación. Asimismo, se ha realizado un modelo teórico del protocolo para el análisis de su rendimiento en sistemas genéricos con tráfico homogéneo. Se ha analizado con detalle el modelo para demostrar las propiedades cuasi-óptimas del protocolo, tanto en retardo como en throughput y estabilidad. El protocolo además introduce un concepto nuevo de control distribuido que minimiza la información de control necesaria, mejorando con ello las prestaciones del sistema. ? Se han realizado simulaciones por ordenador de un sistema de comunicaciones cuyo MAC es el nuevo protocolo propuesto para verificar la validez del model, This thesis provides some new contributions for the development of the future third generation mobile communication systems. This new generation will use a CDMA multiple access technique and pretends to guarantee a certain quality of service in the transmissions. In this sense, this thesis presents new proposals of Medium Access Control Protocols (MAC) and radio resource management algorithms (RRM). These proposals have been presented, studied and analysed in different representative scenarios and it has been proved their suitability for a real communication system. They are also simple to implement and they have a very high efficiency in the use of the transmission resources. Therefore, all of them are promising in order to became part of the future standards. Summarising the main aspects of the thesis, they are: ? The requirements of the radio interface of the future third generation mobile communication systems have been studied in detail, focusing in packet switched mode and CDMA access. ? A new MAC protocol has been proposed to work in this scenario. A theoretical model has been developed in order to obtain its performance in a generic traffic situation. The near-optimum properties of the protocol have been demonstrated. These properties affect delay, throughput and stability. The protocol also introduces a new concept of distributed control, which minimises control information, improving the overall performance. ? Some computer simulations have been carried out to verify the analytic model. It has been proved that the packet delay is minimised and the channel efficiency is almost the maximum theoretical one. Also, the stability is kept for any traffic load. ? A receiver structure for the detection of the access requests has been proposed. This scheme has been studied and analysed, and all the misdetection probabilities have been derived in the presence of a real radio channel with fast fading. The required modifications in the MAC proto, Postprint (published version)

La presente tesis doctoral se enmarca dentro del sector de las comunicaciones móviles, y en particular de los denominados sistemas de tercera generación, que se plantean como objetivo el poder ofrecer una gran diversidad de servicios multimedia bajo unas ciertas garantías de calidad de servicio que difieren sustancialmente de las habitualmente consideradas para los servicios de voz. Bajo esta perspectiva, los sistemas de transmisión por paquetes basados en la técnica de acceso múltiple por división en código CDMA son capaces de llevar a cabo este cometido gracias a la flexibilidad que aportan y a la eficiencia en el uso de los recursos radio. El planteamiento del trabajo ha consistido en identificar un conjunto de funcionalidades en el nivel de acceso al medio MAC para gestionar la calidad de servicio a ofrecer. Éstas son las siguientes: - Protocolo de acceso múltiple: permite a los usuarios acceder al sistema y poder notificar sus necesidades de transmisión. - Algoritmo de gestión de recursos: encargado de ordenar las diferentes transmisiones a la vez que de determinar sus parámetros de transmisión (ganancia de procesado, niveles de potencia, ...). - Estrategia de asignación dinámica de canales (DCA): permite discernir cuales de los recursos son más apropiados para cada uno de los usuarios en términos de interferencia recibida y generada hacia el resto, y presenta interés en un esquema de acceso híbrido por división en tiempo y en código. - Control de admisión: en base a la evaluación conjunta de las anteriores funcionalidades, se determina el límite máximo de usuarios de cada clase de servicio para mantener las garantías de todos ellos. A partir de aquí, el control de admisión es el responsable de garantizar que el número de usuarios en cada caso no supere el máximo establecido. Las diferentes funcionalidades a nivel MAC se sustentan en estrategias de retransmisión apropiadas a nivel de enlace lógico LLC para garantizar la integridad d, The framework for this study are the third generation mobile communication systems, whose main objective consists in offering a diversity of multimedia services under certain Quality of Service (QoS) guarantees. These requirements differ from those usually considered for the speech services in second generation networks. Under this framework, packet transmission systems based on the code division multiple access CDMA strategy present a high flexibility and efficiency in the management of the scarce radio resources to deal with the specified services. A set of functions has been identified in the Medium Access Control layer (MAC) when the CDMA radio resources need to be managed to guarantee a certain QoS. These are the following: - Multiple Access Protocol: It specifies a set of rules to allow users access the system and indicate their transmission requirements. - Radio Resource Management algorithm: It is responsible for ordering the different transmissions while at the same time establishing their transmission parameters (spreading factor, transmitted power, .) depending on the specific QoS for each user. - Dynamic Channel Allocation (DCA) strategy: it decides which are the most suitable resources for each user depending on the measured interference as well as the interference generated to other users. Such a strategy is required in hybrid TDMA/CDMA schemes. - Admission Control: It is responsible for deciding whether a new user can be accepted in the system depending on its required QoS and the requirements of the previously accepted users. After evaluating the overall behaviour of the multiple access protocol, the radio resource management algorithm and the DCA strategy, a limit is found for the maximum number of users that can be accepted for each service class. Then, the admission control mechanism guarantees that the number of users remains always below this limit. The different MAC layer functions make use also of suitable retransmiss, Postprint (published version)

Future third-generation mobile communication systems will need MAC protocols suitable for multimedia CDMA radio communications. DQRAP/CDMA (distributed queueing random access protocol/CDMA) is a general purpose MAC protocol oriented to the CDMA environment. Analytical model expressions and computer simulations have shown its capacity to achieve near-optimum performance under certain traffic scenarios. Starting from the DQRAP/CDMA specification presented in Alonso et al. (2000), we propose some algorithm modifications in order to further improve the system performance when the traffic load is extremely bursty. Computer simulations have been carried out to evaluate this performance improvement, Peer Reviewed, Postprint (published version)

In this paper, an inhibit sense multiple access–direct sequence/code division multiple access (ISMA-DS/CDMA) medium access control protocol for a packet transmission mobile radio network is presented. The main feature of this protocol is its ability to retain the inherent flexibility of random access protocols while at the same time reducing to some extent the randomness in the access in order to increase the system capacity. In this framework, the protocol is presented together with some adaptive mechanisms that improve the protocol performance by means of regulating the access and varying the transmission bit rate according to the channel load that is broadcast by the base station. As a result, an adaptive bit rate algorithm is presented that reaches a throughput value close to the theoretical maximum., Peer Reviewed

In the context of third-generation (3G) systems a mix of services with different requirements are expected. Consequently, packet scheduling mechanisms for quality of service (QoS) guarantees will play a key role. This paper proposes a new scheduling strategy that makes consistent the target quality in the radio link with the priority level assigned to each user. The performance of such a strategy is assessed by system level simulations and, in order to gain more insight into the difficulties of this optimization problem, it is compared to other alternatives. This work is part of the Wineglass project, within the Fifth Framework Program of the European Commission (IST), where a real time demonstrator including the radio resource management tasks is being developed. Thus, an implementation approach of the proposed scheduling is also described. The implementation is based on lookup tables and this approach is validated by simulation., Peer Reviewed

Analytic expressions have been derived for the probability density functions of the total signal-to-interference ratio when considering mixed-type interference sources in the reverse link of a DS/CDMA packet radio system with Rayleigh fading. Four different scenarios were studied, and the corresponding expressions are presented for each situation. The users are divided into two groups: those that apply a closed-loop power control and those that only use an open-loop power control. By making use of these expressions, the mean block error probability is derived as a function of the number of total interfering users in each group., Peer Reviewed

This paper presents a new mechanism that combines the flexibility of an access protocol such as ISMA-DS/CDMA with the ability of a polling mechanism to provide a specific bound for the access delay. This protocol is proposed for a packet transmission mobile communication system together with a scheduling algorithm that arranges the different transmissions depending on the quality of service required by the set of considered services., Peer Reviewed, Postprint (published version)

This paper presents a packet transmission scheme that deals with the problems of a TDD CDMA scenario with different levels of frame structure asymmetry in adjacent base stations by distributing the users in the slots depending on their Time Advance. A multiple access protocol and a scheduling algorithm are also proposed to provide a certain degree of Quality of Service., Peer Reviewed, Postprint (published version)

Code-division multiple-access (CDMA) schemes appear to be very promising access techniques for coping with the requirements of third-generation mobile systems, mainly because of their flexibility. This paper proposes an adaptive S-ALOHA DS-CDMA access scheme as a method for integrating nonreal-time (i.e., Internet applications) and real-time (i.e., voice) services in a multicell scenario by exploiting the potentials of CDMA under time-varying channel load conditions. The adaptive component makes data terminals autonomously change their transmission rate according to the total (voice+data) channel occupancy, so that the minimum possible data delay, which can be analytically obtained by defining a birth-death process, is almost always achieved. Moreover, by means of a simplified cellular model, the proposed algorithm revealed the same behavior, i.e., it tries to select the most suitable transmission rate at any time slot, when it is affected by intercell interference and even by power control imperfections. Finally, in order to gain more insight into the potentials of such an access strategy, the adaptive S-ALOHA CDMA scheme is then compared to a reservation time-division multiple-access (TDMA)-based protocol (PRMA++), showing the benefits of the CDMA-based solution in terms of capacity, flexibility, and data delay performance., Peer Reviewed, Postprint (published version)

En esta comunicación se presenta una estrategia de gestión distribuida para poder garantizar una cierta calidad de servicio en conexiones cuya transmisión se realiza en modo paquete. El entorno de trabajo son los sistemas de comunicaciones móviles multimedia con acceso múltiple CDMA. El esquema global se basa en un protocolo de acceso al medio del tipo DQRAP/CDMA y en una gestión de recursos basada a su vez en un criterio de Crédito pendiente de Servicio y un mecanismo de prioridades por servicio. Se muestra el modelo del sistema y los resultados obtenidos mediante simulaciones por ordenador de cara a validar el esquema propuesto., Peer Reviewed, Postprint (author’s final draft)

This paper presents and analyzes a new near-optimum medium access control (MAC) protocol. The proposed access scheme is suitable for a CDMA mobile communication environment, and keeps under control and upper bounded the number of simultaneous transmissions. It has a delay performance approaching that of an ideal optimum M/M/K system, where K is the number of spreading codes being used (maximum number of simultaneous transmissions). The protocol is a free random access protocol when the traffic load is light, and switches smoothly and automatically to a reservation protocol when traffic load becomes heavier. It is based on distributed queues and a collision resolution algorithm. Moreover, a physical receiver structure is proposed and analyzed in order to preserve the robustness of the protocol in a wireless link. The results obtained show that the protocol outperforms other well known medium access protocols in terms of stability and delay, even when taking into account the loss caused by channel propagation conditions., Peer Reviewed

3G systems are designed for support of a brand new set of services (like location based services) thus, the capability to evaluate their provision in the laboratory is mandatory for their deployment. The IST WINEGLASS project aims to exploit IP-based techniques to support mobility and soft-guaranteed QoS, in a wireless Internet architecture incorporating a 3GPP-UMTS access network (UTRAN) and a WLAN access networks into the same, Peer Reviewed, Postprint (published version)

En esta comunicación se presentan los protocolos de acceso aleatorio ISMA y DQRAP adaptados para sistemas de comunicaciones móviles por paquetes basados en la técnica DS/CDMA. El primero de ellos mejora la eficiencia de los sistemas puramente aleatorios como S-ALOHA gracias a la información que la estación base proporciona respecto del estado de ocupación de los diferentes recursos. A su vez, DQRAP basa su funcionamiento en dos colas lógicas destinadas, respectivamente, a la resolución de colisiones y a la transmisión, lo que permite un acceso más regulado al sistema. Ambos algoritmos son comparados con S-ALOHA, lo que muestra la mejora introducida., Postprint (published version)

This paper presents and analyses a new near– optimum random access protocol. The proposed access scheme is suitable for a CDMA environment and minimises the total number of spreading codes needed to achieve a certain throughput. It is based on distributed queues and a collision resolution algorithm. Computer simulations have been carried out to validate the analytical model and the obtained results show that the protocol has very good stability and delay performance, even compared with medium access protocols using more available spreading codes, Postprint (published version)

This paper presents and analyses a new stable near-optimum random access protocol. The proposed access scheme is adapted for being used in a CDMA environment. It is based on distributed queues and a collision resolution algorithm. The structure of a minislot state detection receiver is presented and analysed in a Rayleigh fading channel situation. Computer simulations have been carried out to validate a system using this medium access control (MAC) and the obtained results show that the protocol has very good stability and delay performance, even taking into account the errors produced by the radio link channel propagation, Peer Reviewed, Postprint (published version)

In this paper an ISMA-DS/CDMA MAC protocol for a packet transmission network is presented. The main feature of this protocol is its ability to retain the inherent flexibility of random access protocols while at the same time reducing to some extent the randomness in the access in order to increase the system capacity. In this framework, the protocol is adapted to a frame structure similar to that specified in the UTRA ETSI proposal for third generation mobile communication systems. Additionally, some adaptive mechanisms are proposed that improve protocol performance by means of varying the transmission bit rate according to the channel load that is broadcast by the base station. As a result, an adaptive bit rate algorithm is presented that reaches a throughput value close to the optimum, Peer Reviewed, Postprint (published version)

The efficiency of MAC protocols for a packet switching DS-CDMA network strongly depends on the offered traffic statistic. For bursty sources where transmission needs are restricted to short message lengths, a protocol such as S-ALOHA can be efficient. However, for longer messages, a reduction in the randomness is required in order to improve the system performance. This improvement can be provided by a protocol such as ISMA when combined with the DS-CDMA technique. In this paper an analytical approach to modeling the resulting ISMA CDMA scheme is presented, and some design issues regarding the number of codes to be used are presented., Peer Reviewed, Postprint (published version)

Peer Reviewed, Postprint (published version)

This paper presents and analyses a new near-optimum medium access control (MAC) protocol. The proposed access scheme is suitable for a CDMA mobile communication environment and minimises the total number of spreading codes needed to achieve a certain throughput. It also has a delay performance approaching that of an ideal optimum M/M/K system, where K is the number of spreading codes being used. The protocol is a free random access protocol when the traffic load is light and switches smoothly and automatically to a reservation protocol when traffic load becomes heavier. It is based on distributed queues and a collision resolution algorithm. Moreover, a physical receiver structure is proposed and analysed in order to preserve the robustness of the protocol in a wireless link. The results obtained show that the protocol outperforms other well known medium access protocols in terms of stability and delay, even when taking into account the loss caused by channel propagation conditions., Peer Reviewed, Postprint (published version)