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

Automated channel emulator based on MEMS switch and improvement of signal transition

Channel Emulator, which is widely used in communication system development, is an instrument that emulates the real-world signal propagation environment between transmitter and. [sic] To overcome the disadvantages of traditional channel emulator, we propose a novel structure of the automated channel emulator in Section 1, which can be controlled by software and integrated into auto-testing system. MEMS switch, with good RF performance, is used to connect and isolate multiple channels. In Section 2, we divide the whole channel emulator system into Channel, Support, and Controller Board, and provide detailed design procedures with critical parameters of each board. The well-designed high frequency channel traces are validated by both 2D/3D simulation models and analytical calculations. The automated control logic and driven mechanism are also illustrated by sequence and block diagram. In Section 3, we perform post-simulation after the completion of PCB layout to check the RF performance of the real PCB board. Then manufacture and assemble the whole system of the automated channel emulator. In Section 4, we study the discontinuities in channel path in a systematically approach, including: channel trace turns, connector transient tapering, wire-bonding and solder parasitic effects. Analysis, simulations and measurements are performed to provide improvement solutions of signal transition. Section 5 concludes this thesis work and discuss about the future plan to expand our channel emulator design to differential solution --Abstract, page iii

Hardware Discrete Channel Emulator

International audienceIn this paper, the emulation environment named Hardware Discrete Channel Emulator (HDCE) has been developed as a coherent framework to emulate on a hardware device (FPGA as the implementation platform in the verification) and simulate on a computer the effect of an Additive White Gaussian Noise (AWGN) in a base band channel. The HDCE is able to generate more than 180 M samples per second for a very low hardware cost, which has been achieved in an efficient architecture. Using the HDCE, the performance evaluation of a coding scheme for a BER of 10−9 requires only one minute of emulation time

Hydroacoustic Channel Emulator - HACE

Kongsberg Maritime wanted a channel emulator for testing their hydroacoustic equipment before deploying it at sea. The benefits of such a system are that it detects problems in an earlier phase of development, thus conveniently reducing the number of expensive sea trials necessary. This master thesis describes how a channel emulator with hydroacoustic properties can be made. The emulator will replace the transducers and water with a computer simulating the acoustics, an audio interface and voltage attenuation. Our approach has been to develop a stable and user-friendly channel emulator with a basis in acoustic wave theory. The hydroacoustic channel emulator, HACE, includes acoustic simulation models where the user is allowed to change acoustic parameters and place the positions of transducers for both point-to-point and network communication. This thesis has focused on advanced acoustic models such as Doppler spread, surface scatter, varying seabed and surface in 3D, sound speed profile with ray tracing, and network communication, together with the fundamental models such as, propagation loss and delay, and reflections. In order to meet the requirements of this master s thesis, with respect to latency and jitter, a good programming platform is important. MATLAB was chosen due to the huge library of built-in-functions, especially with respect to digital signal processing. To control the system a user interface was created with the focus on simplicity, where the interface allows the user to control the system and adjust parameters. The real-time requirement for the system was a latency with a maximum of 100 ms. Since the latency is dependent on both software and hardware, and varies from setup to setup, a calibration function was developed to ensure the best performance for each individual system. HACE has full control over the system latency and exploits it when adding the propagation delay. The minimum latency was measured as 34.2 ms, which resulted in a minimum distance between two nodes using a sound speed of 1500 m/s, being 51.3 meters. For the system to model other distances correctly, this latency must be taken into account when adding propagation delay. Ideally, zero latency would have been preferred so that all distances could be simulated. Two tests were performed to determine the performance of the total system, one that compared the real world impulse response with the simulated impulse response, and secondly to verify the propagation delay in HACE against the measured distance from APOS. The results showed that the simulated ranges corresponded well with the ranges measured in APOS, with an offset of around 20 cm throughout all the results. Impulse response measurements were performed at a sea trial in Horten (Breiangen) measuring at horizontal ranges from 0 to 3000 meters between two nodes. Results from the sea trial compared with those of HACE showed very good similarities between the two, with time deviations between the first and second arrival being from 0 - 3 ms (0 to 15 %), where the largest deviations were found at the shortest ranges

Statistical Analysis of a Channel Emulator for Noisy Gradient Descent Low Density Parity Check Decoder

The purpose of a channel emulator is to emulate a communication channel in real-life use case scenario. These emulators are often used in the domains of research in digital and wireless communication. One such area is error correction coding, where transmitted data bits over a channel are decoded and corrected to prevent data loss. A channel emulator that does not follow the properties of the channel it is intended to replicate can lead to mistakes while analyzing the performance of an error-correcting decoder. Hence, it is crucial to validate an emulator for a particular communication channel. This work delves into the statistics of a channel emulator and analyzes its effects on a particular decoder

LTE Spectrum Sharing Research Testbed: Integrated Hardware, Software, Network and Data

This paper presents Virginia Tech's wireless testbed supporting research on long-term evolution (LTE) signaling and radio frequency (RF) spectrum coexistence. LTE is continuously refined and new features released. As the communications contexts for LTE expand, new research problems arise and include operation in harsh RF signaling environments and coexistence with other radios. Our testbed provides an integrated research tool for investigating these and other research problems; it allows analyzing the severity of the problem, designing and rapidly prototyping solutions, and assessing them with standard-compliant equipment and test procedures. The modular testbed integrates general-purpose software-defined radio hardware, LTE-specific test equipment, RF components, free open-source and commercial LTE software, a configurable RF network and recorded radar waveform samples. It supports RF channel emulated and over-the-air radiated modes. The testbed can be remotely accessed and configured. An RF switching network allows for designing many different experiments that can involve a variety of real and virtual radios with support for multiple-input multiple-output (MIMO) antenna operation. We present the testbed, the research it has enabled and some valuable lessons that we learned and that may help designing, developing, and operating future wireless testbeds.Comment: In Proceeding of the 10th ACM International Workshop on Wireless Network Testbeds, Experimental Evaluation & Characterization (WiNTECH), Snowbird, Utah, October 201

Emulation of Narrowband Powerline Data Transmission Channels and Evaluation of PLC Systems

This work proposes advanced emulation of the physical layer behavior of NB-PLC channels and the application of a channel emulator for the evaluation of NB-PLC systems. In addition, test procedures and reference channels are proposed to improve efficiency and accuracy in the system evaluation and classification. This work shows that the channel emulator-based solution opens new ways toward flexible, reliable and technology-independent performance assessment of PLC modems

Design and implementation of a wide-band real-time mobile channel emulator

A new wide-band mobile channel emulator for the CODIT project is designed and implemented. The UMTS code-division testbed (CODIT R2020) is a research project within the European RACE-II program set up by the Commission of the European Community. Our goal is to be able to simulate in the laboratory, in real time, the multipath propagation found in the mobile radio channel. As code-division multiple access (CDMA) is the access technique within the CODIT project, it was realized that the channel emulator must have simultaneously good delay resolution between propagation paths and long duration of the impulse response. These considerations led to a very flexible channel emulator specifically designed to host the new wide-band channel models developed within the CODIT project. Our emulator features three independent inputs and two outputs, up to 20 complex propagation paths, 10-MHz radio frequency (RF) bandwidth, a delay resolution of 50 ns, and a maximum duration of the channel impulse response of 80 μs. Starting with an explanation of the global structure of the new channel emulator, we derive the optimum design of the interpolation procedures and present the main implementation issues arising from our initial architecture. Finally, we report the results of the laboratory tests of the first prototype of the channel emulator.Peer Reviewe

Evaluation of diversity gains for DVB-T systems

Copyright @ 2008 Eurescom GmbHThe requirements for future DVB-T/H networks demand that broadcasters design and deploy networks that provide ubiquitous reception in challenging indoors and other obstructed situations. It is essential that such networks are designed costeffectively and with minimized environmental impact. The EC funded project PLUTO has since its start in 2006 explored the use of diversity to improve coverage in these difficult situations. The purpose of this paper is to investigate the performance of transmit and receive diversity gains with two antennas to improve the reception of DVB-T/H systems operating in different realistic propagation conditions through a series of tests using the Spirent dual channel emulator