Jarkko Paavola

Aggregated Renewal Markov Processes With Applications in Simulating Mobile Broadcast Systems

For purposes of simulating contemporary communication systems, it is, in many cases, useful to apply error models for specific levels of abstraction. Such models should approximate the packet error behavior of a given system at a specific protocol layer, thus incorporating the possible detrimental effects of lower protocol layers. Packet error models can efficiently be realized using finite-state models; for example, there exists a wide range of studies on using Markov models to simulate communication channels. In this paper, we consider aggregated Markov processes, which are a subclass of hidden Markov models (HMMs). Artificial limitations are set on the state transition probabilities of the models to find efficient methods of parameter estimation. We apply these models to the simulation of the performance of digital video broadcasting-handheld (DVB-H). The parameters of the packet error models are approximated as functions of the time-variant received signal strength and speed of a mobile vehicular DVB-H receiver, and it is shown that useful results may be achieved with the described packet error models, particularly when simulating mobile reception in field conditions.

Development and Applications of a Dynamic DVB-H System-Level Simulator

This article discusses the need for dynamic system-level simulations for Digital Video Broadcast - Handheld (DVB-H), specifically to evaluate the overall system performance perceived by mobile users dynamically over time. Such simulations can be used as a complement of traditional radio coverage planning tools for analyzing quality of service and radio resource management aspects of the DVB-H network. The article describes a general simulation structure, the main models required, and measurement-based validation of a DVB-H physical layer performance model that enables these analyses. The article also provides illustrative applications of the simulator.

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.

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.

Precoding Welch-bound signature sets

In this paper signal-to-interference ratio for precoded Welch-bound signature sets is derived for oversaturated synchronous CDMA system. For this, a novel definition for CDMA precoding is given and a general correlation result is presented. It is shown that the system with precoding outperforms the system without it, assuming that conventional receiver is used.

On the performance and efficiency of Generic Stream Encapsulation combined with LDPC coding for the terrestrial DVB systems

Generic stream encapsulation (GSE) provides a simple and efficient method to encapsulate network layer packets to a format suitable for the physical layer. The performance of GSE is considered in this paper through overhead calculations and simulations over four physical layer configurations. The results are compared to the results of multi-protocol encapsulation (MPE) with Transport Stream multiplex. The combined effect of encapsulation and forward error correction is taken into account also.

Precoding for improved performance of Welch-bound signature sets

Welch-bound signature sets are optimal for oversaturated synchronous CDMA in terms of minimizing the multiple access interference. In this paper, precoding of the sum signal of Welch-bound signatures, in order to maximize the mean signal-to-interference ratio for conventional receivers, is analysed. The gain compared to normal sum signal is calculated, and also the effect on the energy of the sum signal is derived.

Oversaturated Group Orthogonal CDMA in Multipath Channels using Chip Interleaving with Zero Padding

Oversaturated group orthogonal CDMA (GO-CDMA) offers an elegant way of increasing capacity of synchronous DS-CDMA, which allows existence of number of users exceeding signal space dimension. The system provides excellent results in synchronous single-path channels; however, in multipath channels complicated equalizers of big length are required to secure good performance due to significant MAI. In this paper implementation of chip interleaving with zero padding in GO-CDMA system is considered to alleviate the effect of MAI. It is shown that this approach results in bit-synchronous multipath signals at the receiving end. Computer simulations demonstrate that in such a system the usage of the simplest zero-forcing equalizer of moderate length provides performance very close to that of GO-CDMA in an AWGN channel.

Asynchronous Oversaturated Group Orthogonal CDMA Using Chip Interleaving with Zero Padding

In this article we consider usage of chip interleaving with zero padding in oversaturated systems. It is shown that this approach makes user signals at the receiving end bit-synchronous independently of the user delay profile, making thus chip group orthogonal (GO-CDMA) applicable in asynchronous transmission conditions as well. Theoretical calculations and computer simulations demonstrate that at high signal to noise ratio (SNR) values the performance of the system is equivalent to the one operating in synchronous channels.