This Innovative Practice Full Paper presents our methodology and tools for introducing competition in the electrical engineering curriculum. Our focus is on the education of advanced wireless communications technologies and systems. We leverage software radio technologies and open-source software frameworks to design hands-on laboratory exercises and a grading system based on competition. The motivation behind this is to potentiate creativity while unleashing the boundaries of traditional hands-on laboratories. The students form teams and use the open-source software radio framework ALOE and a partially defined protocol that implements a simplified version of the long-term evolution (LTE) standard in software. The proposed student challenge follows the Spanish soccer league format LaLiga, which consists of weekly matches and accumulative scores. The students are tasked to build an optimized transmitter and receiver following the LTE standard guidelines. The evaluation metric is link performance. The students learn how to (1) assess the feasibility, key challenges and costs for meeting the requirements of wireless communications systems, (2) analyze alternative radio design options and argue about their benefits and drawbacks, and (3) develop strategies and solutions to software radio engineering problems. We discuss our experiences and lessons learned with focus on the suitability of the proposed teaching methodology and evaluation process. Whereas the methodology is well perceived by the students, our analysis shows that the competitive scoring mechanism needs further adjustments.

This Innovative Practice Full Paper presents our methodology and tools for introducing competition in the electrical engineering curriculum to accelerate education and innovation in wireless communications. Software radio or software-defined radio (SDR) enables wireless technology, systems and standards education where the student acts as the radio developer or engineer. This is still a huge endeavor because of the complexity of current wireless systems and the diverse student backgrounds. We suggest creating a competition among student teams to potentiate creativity while leveraging the SDR development methodology and open-source tools to facilitate cooperation. The proposed student challenge follows the European UEFA Champions League format, which includes a qualification phase followed by the elimination round or playoffs. The students are tasked to build an SDR transmitter and receiver following the guidelines of the long-term evolution standard. The metric is system performance. After completing this course, the students will be able to (1) analyze alternative radio design options and argue about their benefits and drawbacks and (2) contribute to the evolution of wireless standards. We discuss our experiences and lessons learned with particular focus on the suitability of the proposed teaching and evaluation methodology and conclude that competition in the electrical engineering classroom can spur innovation.

Radio communications terminals and infrastructure tend to support an increasing range of algorithms and radio access technologies. Flexible processing platforms are therefore needed for supporting multi-standard or heterogeneous radios. Channel decoding is one of the most computing demanding digital signal processing blocks of a radio transceiver. At the same time, it provides a high degree of implementation flexibility as well as facilitates dynamic parameter adjustments. This paper presents a flexible LDPC decoder implemented on an FPGA device following the ALOE middleware design paradigm. We analyse the middleware efficiency in terms of flexibility versus resource requirements. The results show a relative middleware area overhead of 32 %.

It is widely known that the SDR industry campaigns component-based radio applications, which will enable fast prototyping and deployment of new radio devices and may increase manufacturing profits. Through the JTRS program, the US Dept. of Defense proposed the SCA specification as the standard for military communications. The SDR Forum is now reviewing these specifications and trying to adapt them to the commercial market. The significant differences between military and commercial communications' requirements make this migration a hazardous task. On the other hand, the SCA specification does not consider any method or procedure that enables cognitive functionalities, which would be necessary for future cognitive radio implementations. This paper therefore presents an alternative approach to SCA, introducing a low-profile operating environment for next generation cognitive radios. We demonstrate its suitability for present and future commercial radios.

Cognitive radio characterizes an ambient aware and software-defined radio system that is capable to autonomously and intelligently adjust the system parameters. It has the potential to optimize the usage of all relevant resources for service- driven wireless communications. We identify four types of resources; these are the radio, the computing, and the radio and user application resources. This paper presents their modeling, including several models for each resource type. The modeling serves as the basis for a joint resource management in a cognitive radio system that may eventually trade-off one resource (type) against the other(s). Two approaches for such a management are presented: a distributed-cooperative and a centralized- integrated. We finally discuss the applicability and utility of the proposed models, and the potentials of a joint resource management in cognitive radio in terms of user satisfaction and revenues.

Software-defined radio (SDR) is an emerging concept that leverages the design of software-defined and hardware-independent signal processing chains for radio communication. It introduces flexibility to wireless systems, facilitating the dynamic switch from one radio access technology to another or, in other words, the de- and reallocation of computing resources from one SDR application to another. This paper introduces an SDR computing resource management framework. It accounts for several SDR system characteristics, including real-time computing requirements, limited computing resources, and the use of heterogeneous multiprocessor plat-forms, including multiprocessor systems-on-chip. The framework features the tw-mapping, a dy-namic mapping algorithm that is apt for many cost functions and, thus, adaptable to any radio scenario. The cost function proposal dynamically manages the available computing resources to satisfy the given SDR computing constraints. Two relevant SDR scenarios and the corresponding simulations, based on representative SDR platforms and processing chains, demonstrate the framework's importance and suitability for software-defined radios.

Cognitive radio is generally understood as an intelligent wireless communication system aiming at the efficient utilization of radio resources. We argue for the extension of its scope to also address the management of computing resources, including processing and bandwidth capacities of SDR platforms, and present a cooperative resource management framework: The joint radio resource management (JRRM) and the computing resources management (CRM) entities interchange information to cooperatively decide if and what kind of terminal reconfiguration would be the most appropriate in each situation. Therefore, the cognitive radio system continuously observes the radio and the computing environments. We discuss a realistic case study and present a simple CRM algorithm. Simulation results show that such a cooperative resource management approach can achieve important improvements over the JRRM by itself. In particular, our proposal considerably reduces the number of lost user sessions due to inappropriate reconfiguration decisions and, thus, serves more wireless users.

Due to the wireless industry tendencies, different radio access technologies will coexist in a heterogeneous environment. Software defined radio, as a concept that tries to provide flexibility, might ease the integration of that environment. The goal of this work is to introduce the concept of computing resource management, that working in cooperation with the radio resource management strategies leading to minimize computing costs assuring the same or better QoS in such future heterogeneous systems. Furthermore, the action of computing management might help to bring balance over the communication load.

The division in several layers of the implementation of systems is a solution adopted to avoid complexity, provide flexibility and improve portability and code reusability through different hardware. Middleware (intermediate layer between two other layers) implementations are based on the use of increasingly high-level languages and application programming interfaces (API). The field programmable gate arrays (FPGA) world can also apply this approach to produce building blocks independent from hardware platforms and devices. This paper presents details of the implementation of a middleware, called platform and hardware abstraction layer (P-HAL) when applied to FPGA devices. It was specially designed for radio applications and allows designing specific functions independently of the hardware context where they are applied, thus providing flexibility to the so-called software radios employing FPGA devices.

This paper develops a feasible architecture for end-to-end QoS management over B3G networks where multiple heterogeneous radio access networks (RAN) can be coordinated at radio level by means of supporting common radio resource management (CRRM) functionalities. The presented approach is claimed to be innovative as long as it is inspired in the most relevant trends being developed in different fields and forums and come up with a global solution capturing such partial concepts. A key point of the architecture is the introduction of a wireless QoS broker entity that becomes the link between CRRM and E2E QoS management. In the paper, after introducing the proposed QoS framework, the signaling and procedures to support such architecture in the B3G network are addressed. Over such a basis, a connection establishment procedure is discussed to show how the problem of initial RAN selection can be managed by the proposed architecture.

Software Defined Radio (SDR) is an emerging technology that is based on the software implementation of the signal processing blocks found in a radio transceiver. The switch between radio access technologies may then be as easy as changing the software running on a future SDR terminal. SDR terminals refer to mobile equipment and base stations. These terminals will comprise general purpose processors, digital signal processors and/or reconfigurable logic devices. As a result, typical heterogeneous computing problems may appear in the SDR context. This article focuses on the mapping issue, discusses its relevance in software defined radio, and introduces an adequate mapping algorithm. The algorithm efficiently tackles the problem of mapping SDR function chains, i.e. signal processing blocks of a SDR transceiver, to heterogeneous processing platforms. We expose our approach, discuss its performance, present extensive simulation results and derive conclusions.

In the B3G system considered, which is based on the 3GPP UMTS architecture, the initial hypothesis made in this paper, is that the QoS management of the IP access network is taken in charge by a bandwidth broker. A pre-handover signalling for QaS-aware path selection is investigated with the goal of achieving the "always best connected" paradigm. Furthermore, the scalability of the proposed scheme is analysed taking into account the overhead due to IP micromobility, QoS routing, CRRM and bandwidth broker

Software radio applications require a framework to develop and deploy applications, especially those related to radio infrastructure. It is interesting that a given application may be executed on any software radio. But, since hardware platforms used in this context will have multiple architectures and devices, a software layer to make applications independent from hardware is mandatory. Ad-hoc software for a given hardware platform may produce the best software performance. Conversely, when software is not targeted to any concrete platform the lost of performance may be excessive and the overhead introduced by any platform-dependent library could become intolerable. In this paper the resource utilization of a software radio application using a simple hardware abstraction layer is studied and compared to an ad-hoc implementation to make an assessment of the introduced overhead. The particularity of the hardware abstraction layer is that it runs on a platform which only processors are FPGA devices.

Software radio will have an important role in future terminal and base station definition. Although the ideal software radio architecture is highly restricted by technology, at present it is possible to build complex systems completely customised and reconfigurable using FPGA devices. They provide the designer with the possibility of modifying the hardware functional qualities without giving up high performance or using resources poorly. To check how important is this affirmation considering future wideband systems, a representative DS-CDMA subsystem has been built over an FPGA platform that allows fast reconfiguration of internal system blocks.

For a given channel allocation, the capacity and quality of communications of cellular radio systems using direct sequence/code-division multiple-access (DS/CDMA) can be increased by using a transmitter power control scheme to combat the near-far problem. Centralized and distributed transmitter power control schemes used to minimize the outage probability due to cochannel interference in cellular radio systems have been investigated in previous papers. In these papers, however, the effect of adjacent channel interference (near-far problem) is neglected. The goal of our paper is, based on the previous papers models and ideas, to investigate transmitter power control strategies appropriate for DS/CDMA high capacity cellular radio systems. Monte-Carlo simulation results of these power control schemes indicate that substantial system capacity gains can be obtained with respect to conventional systems. It is also shown that the performance of properly designed distributed algorithms can closely approximate that of the optimum centralized power control scheme.

This paper presents an analysis of soft-output equalization and coding techniques applied to 4 and 16-QAM TDMA radio systems for frequency selective fading channels. In particular, typical urban and hilly terrain environments have been considered. The use of the soft information provided by the equalizer enhances the system performance considerably. Specifically, an improvement of more than 4 dB can be achieved in relation to hard decoding techniques. The necessity of introducing some interleaving in order to destroy the channel memory has also been stated. The actual investigated equalizers have been a soft-output decision-feedback equalizer (SODFE) and a soft-decision M-algorithm (SDMA) jointly with convolutional coding and both ideal and finite interleaving.

A Monte Carlo simulation study of a combined FDMA/TDMA slow frequency-hopping trellis coded adaptive receiver for multipath Rayleigh fading channels is presented. The receiver structure, first proposed by Proakis (1989) and then developed by Ralf Mehlan and Heinrich Meyr (1992) for use on HF fading channels, comprises decision feedback equalizer (DFE), block deinterleaver and TCM decoder in one unit. Antenna diversity is considered leading to a joint diversity and combined equalization/decoding scheme. Furthermore, cyclic slow frequency hopping is used to attain intrinsic frequency diversity to perform a near ideal channel interleaving with a short processing delay. In order to asses the performance of this scheme Monte-Carlo simulations of the system have been carried out where the dynamic behavior of the mobile radio channel has been simulated by means of a selective equal-energy two-ray Rayleigh model, with a variable delay, /spl tau/, between the two rays. Bit error rate (BER) is obtained as a function of signal-to-noise ratio (SNR) and with /spl tau/, Doppler spread, number of frequencies in the frequency-hopping pattern, number of DFE coefficients and TDMA frame length as parameters.>