Tero Jokela

The Performance Analysis of MPE-FEC Decoding Methods at the DVB-H Link Layer for Efficient IP Packet Retrieval

DVB-H is a new broadcasting standard, which offers reliable high data rate reception of IP packets for mobile handheld battery-powered devices. A link layer with multiprotocol encapsulation (MPE), including Reed-Solomon forward error correction (FEC) combined with a cyclic redundancy check (CRC), is defined in the standard to work on top of the DVB-T physical layer. For error correction in the receiver the DVB-H standard suggests to use erasure decoding based on the CRC information. Yet, the decoding method is not strictly determined in the standard. This paper investigates the performance of five different Reed-Solomon decoding schemes for the DVB-H link layer forward error correction called MPE-FEC. They differ on utilization strategy of existing erasure information. The performance of different decoding methods are evaluated analytically in an binary symmetric channel (BSC) and with simulations in the additive white Gaussian noise (AWGN) and a mobile fading channel. For the simulations in the fading channel a packet channel model based on actual measurements is designed. It is shown that more sophisticated decoding methods than the one suggested in the standard are required for efficient retrieval of IP packets

Robustness analysis of physical layer signaling transmission in DVB-T2

Second generation terrestrial video broadcasting standard DVB-T2 is intended for delivery of HDTV services to users in the terrestrial broadcasting networks. In this paper the robustness of the DVB-T2 physical layer signaling is compared to the robustness of the application data and a method for selecting proper transmission parameters for the signaling is proposed.

Reed-Solomon Decoding Algorithms and Their Complexities at the DVB-H Link-Layer

DVB-H (digital video broadcasting for handheld terminals) is a data broadcasting standard based on DVB-T (digital video broadcasting - terrestrial) that enables delivery of various Internet protocol (IP) based services to mobile receivers. To combat the effects of mobility, a forward error correction (FEC) scheme called MPE-FEC is introduced at the link layer. Different mechanisms for decoding the link layer MPE-FEC based on Reed-Solomon (RS) code have been suggested, but their effect on the decoding complexity as compared to the standard solution has not been analyzed so far. Yet, the complexity is still a crucial issue in battery powered portable devices. In this paper, complexities of different RS decoding algorithms together with their application in DVB-H are analyzed.

Agile methods in embedded system development

Examines three cases on applying agile practices into embedded system development.Visibility of work and system-wide understanding increased.Improved communication diminished the need for internal documentation.Slow hardware development and specialization of team members challenged agile methods.If not possible to present working product, visualize the progress in other ways. Agile methods are widely utilized in software development but their usage in embedded system development is often limited to software. A case study of three industrial cases was carried out to understand how to tailor agile methods effectively including also hardware development.Agile practices, mostly derived from Scrum, were tailored to fit the needs of each team and the method development was closely followed. Surveys conducted in the beginning and in the end of the cases were compared and complemented with interviews to understand the new working methods and their effects.Case evidence shows that interdependencies between work of each developer were taken into account better, visibility over the whole product increased and need for internal documentation diminished due to improved communication, but dividing hardware tasks into iterations was experienced difficult. With some tailoring, agile practices are beneficial also in the embedded system development.To successfully adopt agile methods into embedded system development, the team must consist of all the project members, the natural cycle lengths of different disciplines and different knowledge between the developers must be accepted and built upon, and the progress of the product must be presented or visualized in the end of each iteration.

Performance evaluation of 4×2 MIMO schemes for mobile broadcasting

The utilization of multiple antennas in transmitters and receivers (MIMO) in communication systems allows for increased robustness of the received signal or increased bit rate. These both are important factors in the design of communication systems. The introduction of MIMO for broadcasting systems is currently considered for DVB-NGH (Digital Video Broadcasting - Next Generation Handheld). In this paper the performance of selected Space Frequency Block Codes (SFBCs) is investigated in mobile environment with four transmitter and two receiver antennas. In addition, the effect of having a strong forward error correction code on top of SFBC is investigated by studying the effect of MIMO schemes on DVB-T2 (Second generation Terrestrial) based system.

Performance Analysis of Different Reed-Solomon Erasure Decoding Strategies at the DVB-H Link Layer

DVB-H is a new broadcasting standard, which offers reliable high data rate reception for mobile handheld and battery-powered devices. A link layer, including Reed-Solomon error correction combined with cyclic redundancy check (CRC), is defined in the standard to work on top of the DVB-T physical layer. The DVB-H suggests to use an erasure decoding method based on CRC information. Yet, the decoding method is not strictly determined in the standard. This paper investigates the performance of four different Reed-Solomon erasure decoding schemes for DVB-H link layer forward error correction

Suitability of ITU-R P.1546 propagation predictions for allocating LTE SDL with GE06

The compatibility of Geneva 2006 frequency plan (GE06) assignments and allocations for digital terrestrial television (DTT) is determined using ITU-R P.1546 propagation prediction method. The aim of this paper is to study the suitability of using ITU-R P.1546 propagation predictions for allocating Long Term Evolution (LTE) Supplemental Downlink (SDL) to broadcast Audiovisual Media Services (AVMS) in the UHF TV band. This paper presents a field measurement campaign to study the accuracy of P.1546 propagation predictions for LTE base station signals in the close vicinity of the LTE base station, where DTT reception interference and overloading events are most likely to occur. The ITU-R P.1546 prediction signal strength in general was higher than the measured field strength, which means that using ITU-R P.1546 propagation predictions could thus overestimate the probability of interference events to DTT reception. The paper also studies use of more sophisticated site-specific propagation prediction methods, but the considered short-range propagation paths were found to be very difficult to predict regardless of the used method. The location-by-location analysis indicates that the propagation predictions are less accurate in the locations where the line-of-sight (LOS) or first Fresnel zone are obstructed.

Interference measurements for Licensed Shared Access (LSA) between LTE and wireless cameras in 2.3 GHz band

This paper presents interference measurements for spectrum sharing between Long-Term Evolution (LTE) network and wireless cameras in the 2.3-2.4 GHz band under the new Licensed Shared Access (LSA) concept. The introduction of wireless broadband (WBB) communications services in this band is currently under study in European regulation and standardization. If the band cannot be cleared, a potential implementation option is the LSA approach, which maintains the protection of the current incumbents while introducing WBB as an additional licensed system within the band. Defining the incumbent protection criteria is critical and will require field measurements. The incumbents operating on the band in Finland and many other European countries are Programme making and special events (PMSE) wireless cameras. This paper presents results from an interference measurement campaign conducted in Ylivieska, Finland, where the aim was to study the interference from real LTE WBB system to a professional level wireless camera link on the 2.3 GHz band using the Finnish LSA trial environment. The measurements were planned to reproduce the cordless camera link scenario in ECC report 172, which provides compatibility studies with respect to the potential usage of the 2.3 GHz band for WBB systems. The results indicate that coexistence between LTE and wireless camera link can be feasible in the measured cordless camera link scenario in adjacent or larger separation channels. The measurement results are slightly less restrictive than the theoretical results in the ECC report, which came to the same conclusion about the feasibility. However, further study is required to derive actual incumbent protection criteria.

Evaluation of the distributed MISO gain for mobile broadcast planning in real scenarios

This paper analyzes the impact produced by the use of distributed MISO diversity techniques on the network planning for mobile broadcasting services, compared with the rest of variables considered in the design of these networks. In order to do that, we have evaluated the results obtained from the simulation of a wide variety of real cases of study, where different deployment topologies and different types of service scenarios have been considered. For all the cases analyzed, the results show evidence that the use of distributed MISO techniques does not provide a significant improvement in the coverage and a low impact compared to the rest of variables considered in the network design.

A computationally efficient simulation chain for OFDM-based wireless systems

We present a method for modeling OFDM transmission over time- and frequency-selective fading channels using finite-state hidden Markov models. The proposed approach has improved fading autocorrelation accuracy compared to previous related models. Also, we present a way of producing log likelihood ratio values as output of the finite-state model for any signal constellation. As a case study, we configure the proposed model according to the second generation terrestrial digital video broadcast system operating over a typical urban mobile channel.