Many broadband services are based on multimedia applications, such as voice over internet protocol (VoIP), video conferencing, video on demand (VoD), and internet protocol television (IPTV). The combination "triple-play" is often used with IPTV. It simply means offering voice, video and data. IPTV and others services uses digital broadband networks such as ADSL2+ (Asymmetric Digital Subscriber Line) and VDSL (Very High Rate DSL) to transmit the data. We have formulated a MDP (Markov Decision Process) for a triple-play transmission on DSL environment. In this paper, we establish the relationship between DSL transmission characteristics and its finite-state Markov model for a triple-play transmission system. This relationship can be used for a resource management for multimedia applications delivered through a broadband infrastructure. The solution to our optimization problem can be found using dynamic programming (DP) techniques, such as value iteration and its variants. Our study results in a transmission strategy that chooses the optimal resource allocation according the triple-play traffic requirements, defined in technical report TR-126 (Triple-Play Services Quality of Experience Requirements) from DSL Forum, minimizing quality of service (QoS) violations with respect to bandwidth. Three traffic classes (video, audio, and best effort internet data) are defined and analyzed. Our simulation results show parameters like as blocking probability for each class, link utilization and optimal control policies. The MDP-based approach provides a satisfactory way of resource management for a DSL system.
The Brazilian Amazon has sui generis characteristics that affect strongly the communication technologies, such as high humidity and temperature. These characteristics cause impact in the existent infrastructure, especially in twisted-pair copper lines. At the moment, new services are based on multimedia applications, as voice over internet protocol (VoIP), video on demand (VoD), and internet protocol television (IPTV). Such services use digital broadband networks such as ADSL2+ (Asymmetric Digital Subscriber Line) to transmit the data. Broadband services require data rates which can only be achieved by using relatively high spectrum frequencies. At high frequencies the DSL signal is more susceptible to external noise sources, such as radio frequency interference and impulsive noise. For this purpose, an experimental setup has been built at UFPA that consists of noise generator, traffic generator, real cables, modems and DSLAM (digital subscriber line access multiplexer). This paper aims at characterizing how the noise impacts on triple play services for a broadband system using a DSL loop on Amazon environment. The objective of the noise impact experimentation is to observe the behavior of a DSL system under more realistic but controlled line conditions. Metrics as lost packet, jitter, latency, and throughput are used to characterize the triple play service in a DSL loop under the noise impact. Through the real experiments and controlled loop conditions, this paper allow identify, from application level point of view, how robust DSL system is in respect to noise occurrence. Additionally, it is described a methodology for noise impact measurements using a DSL system.
The increasing trend of triple play traffic transmission (voice, video and data) over internet is a worldwide phenomenon.
However, to get a satisfactory communication, we need study the process on end-the-end way. Into regions with little
infrastructure of telecommunications, one of the concerns is about used technologies of access. This work presents an
analysis based on an IPTV (Television Internet Protocol) transmission generated on two combined technologies of
access, PLC (PowerLine Communications) and ADSL2+ (Asymmetric Digital Subscriber Line), using a combination of
electric network and telephony infrastructure, called of pDSL. This technology is a viable combination for regions with
poor infrastructure of telecommunications. The results are evaluated with intention to present the viability of this kind of
the telecommunication environment and with a simulation for extrapolation study.
Broadband services require data rates that can only be achieved by using relatively high spectrum frequencies. At such
high frequencies, the DSL (Digital Subscriber Line) signal is more susceptible to external noise sources, such as radio
frequency interference and impulsive noise. This paper aims to characterize how the impulsive noise impacts on services
and applications for a broadband system using an ADSL2+ loop. The first approach was to use the impulsive noise
defined in the standards G.996.1 (Test Procedures for DSL Transceivers) from ITU-T and TR-048 (ADSL
Interoperability Test Plan) from DSL Forum. In this approach we have also used a HDSL (High Bit Rate DSL) and white
noise disturbers on the line. The impulsive noises c1 and c2 (defined in G.996.1) are injected into the circuit at the CO
(Central Office) end and CPE (Customer Premises Equipment) end of the loop simulator. Additionally, it was analyzed
the spikes of noise's impact on the ADSL2+ line. In this case, pre-defined models of NEXT (Near-end crosstalk) and
white noise are injected on CO and CPE side, simultaneously. Metrics like packet rate, lost packet count, bandwidth,
short-term average transfer delay, and errored seconds are used to characterize the DSL loop under the noise impairments.
In order to qualify a subscriber loops for xDSL transmission, basic parameters like transfer function, scattering parameter S11 and characteristic impedance should be known. The aim of this paper is to present a test methodology for measurements of these basic parameters. The characteristic impedance is measured by open/short method and it is compared with the terminated measurement method defined in IEC (International Electrotechnical Commission) 611156-1. Transfer function and scattering parameter S11 of DSL loop are also measured on a real cable. The methodology is based on measurements of a 0.4 mm, 10 pairs, balanced twisted-pair cable of 1400 m of length. In order to improve the analysis of results, we compared the measurements from real cable with results from wireline simulators. The measurement of parameters of xDSL copper loop is done in an infrastructure set up in the LABIT (Technological Innovation in Telecommunications Lab) at UFPA (Federal University of Para), that consist of a wireline simulators, a precision impedance analyzer, and a network analyzer. The results show a difference between the measurements performed with real cables and wireline simulators for transfer function parameter. Characteristic impedance obtained by both methods presented quite similar results.
This paper presents methodologies that could be used for characterizing subscriber telephone loops that carry DSL services (ADSL and ADSL2+), by determination and analysis of frequency response, time domain reflectometry, and impulse response of the line. From this analysis, the subscriber loop length, identification and location of impairments such as bridged taps, gauge changes, and open ended termination across the line are carried out. To verify the methodologies presented, results obtained from measurements are drawn and compared to results obtained from computational simulations.