High Bit Rate Digital Subscriber Line - Overview (2023)

HDSL is a scheme that uses two pairs to provide bidirectional transport (DS1) at 1.544 Mb/s to cover the entire CSA area.

Von:Visual Communication Manual, 1995

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demodulator
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Whitham D. Reeve, emEncyclopedia of Physical Science and Technology (Third Edition), 2003

VIII High Bitrate Digital Subscriber Line

O originalhigh bit rate digital subscriber line(HDSL) was implemented on the public network in the early 1990s and carries the user's DS-1 speed signal over two bidirectional twisted-pair loops, each operating at 784KB/s. With a technique calleddouble duplex transmission, each of the two loops carries half of the total payload at 768 kb/s plus 8 kb/s DS-1 frame and additional 8 kb/s HDSL overhead. HDSL was designed to allow rapid deployment of DS-1 speed services without the high engineering and loop installation costs associated with repeated T1 carrier. Unlike T1 carrier, HDSL can be used on bridged tap loops, which are unterminated wire pairs connected to the live wire pairs used for HDSL service. Development of a standard for an improved version called HDSL2 was completed in the late 1990s. HDSL2, or second-generation HDSL, requires only one pair of wires but offers the same DS-1 speed interface as HDSL. Both HDSL and HDSL2 are only used for peer-to-peer applications.

HDSL was originally conceived as a repeaterless technology, but manufacturers have developed line repeaters to double and triple the loop length to 24,000 and 36,000 feet from the original maximum of 12,000 feet. The HDSL2 was designed from the ground up to use a line booster or two to extend range up to 36,000 feet. If anything 26-ga. If the cable is present on HDSL loops, the range will be reduced to up to 9,000 feet per repeated segment.

Figure 17shows how HDSL endpoints are implemented.Figure 18shows a typical HDSL application. HDSL2 can be used in the same applications as HDSL, but HDSL only requires half as much external equipment to do the same job. The HDSL terminal equipment (HTU-R) normally receives electrical power from the HDSL central terminal equipment (HTU-C). On the network side, the HTU-C provides a standard signal that is compatible with existing digital signal DSX-1 cross-connect equipment in central offices and is therefore transparent to the network. The HTU-R can be programmed to provide a DSX-1 compliant signal or an industry standard digital signal rate signal to the user's DS-1 network interface. The latter uses a slightly different pulse pattern that detects the different types of wiring encountered in the user's premises. With HDSL2, the two end devices are referred to as H2TU-C and H2TU-R.

High Bit Rate Digital Subscriber Line - Overview (1)

High Bit Rate Digital Subscriber Line - Overview (2)

The HDSL loopback interface uses the 2B1Q line code, which is identical to that used on the ISDN digital line described earlier. When user data is presented to the HTU-C or HTU-R, it is encoded and interleaved with the (upper) bits of the O&M channel and then combined with the synchronization bits, as in the digital ISDN line.

The shape and width of the pulses on the loop interface are identical to the ISDN BRI digital line, but the pulse width is different to accommodate the higher signaling rate. With HDSL, the pulse width is given in a unit interval of 2.55 µs. The basic pulse shape is the same for all quat values, the only difference being the polarity and voltage of the pulse. The HDSL line rate of 784 kb/s on each of the two loops corresponds to a symbol rate of 392 kbaud. Since each of the two HDSL loops is bidirectional, 2- to 4-wire hybrid couplers and echo cancellers are required to prevent the transmitted signal from interfering with the received signal. The techniques are identical to those described for the ISDN BRI digital trunk.

HDSL2 digital loopback also uses echo cancellers and hybrid couplers; however, it is unique in its application of a one-dimensional, trellis-coded, 16-level pulse-amplitude-modulated (TC-PAM) line code. The HDSL2 pulse characteristics are controlled by controlling the power spectral density (PSD) of transmitted signals using programmable filters. Although HDSL2 offers symmetric transmission, upstream and downstream PSD are different but overlap (Figure 19). Controlled PSD is required to control crosstalk interference between digital loops that share the same twisted pair cable. Spectrum compatibility and crosstalk control are critical to the compatibility of old and new loop technologies. Basic TC-PAM techniques have also been adopted for SHDSL, which is a faster and adaptable version of HDSL2, but the PSD masks are slightly different. The modulation techniques used by HDSL2 result in much more complex interface equipment (integrated chipset) than the original HDSL.

High Bit Rate Digital Subscriber Line - Overview (3)

Trellis coding is a form of Forward Error Correction (FEC) that encodes transmitted signal points in a convolutional fashion (the term "trellis" refers to the appearance of the path diagram representing encoder state changes). A trellis encoding algorithm adds redundancy when acceptingSubwayBits of data as input and generationSubway+1 bit as output. It is useful on channels with limited bandwidth as it provides FEC without increasing bandwidth requirements. In the case of HDSL2, three bits of data are input into the trellis encoder and four bits are sent (Figure 20).

High Bit Rate Digital Subscriber Line - Overview (4)

Trellis encoding combines FEC modulation/encoding and FEC demodulation/decoding into an integral operation that effectively increases the minimum spacing between the signals most likely to be confused in the decoder at the other end of the loop. The sequences of symbols encoded in the trellis are constrained to certain valid patterns. These patterns are chosen to have a large minimum distance between them so that corrupted sequences can be corrected, thus reducing the likelihood of errors in the decoded signals.

The four trellis encoder bits are assigned one of 16 specific levels by the PAM line encoder, as shown inTable X. Each mapping level corresponds to one of 16 PSD masks (numbered 0 to 15), separated by 1 dB. The total power in mask 0 is about +16.5 dBm, which corresponds to a voltage level of about 2.5 volts, and in mask 15 is +1.5 dBm, which corresponds to a voltage level of about 2.5 volts of about 437 mV. The HDSL2 line rate is 1.552 Mb/s and the symbol rate is 1552 ÷ 3 = 517.33 kb/s.

(Video) Last mile technologies: Dial-up & DSL

TABLE X. HDSL2 line code assignment

Binary bit groups	*attribution levelx(Subway)*
0000	−15/16
0001	−13/16
0010	−16.11
0011	-16/09
0100	−7/16
0101	−5/16
0110	−3/16
0111	−1/16
1100	+1/16
1101	+3/16
1110	+5/16
1111	+7/16
1000	+9/16
1001	+11/16
1010	+13/16
1011	+15/16

A high internal digital signal processing load, e.g. B. With HDSL2 and SHDSL, it increases the loop transmission latency. Latency, as applied to digital loops, is the delay introduced when a user bit enters the DSL interface at one end and when it leaves the associated DSL interface at the other end. All digital network nodes increase latency when transporting user data from one end to the other. Real-time applications such as voice and live video are very sensitive to delay. HDSL2 specifies a latency of no more than 500 µs and SHDSL specifies no more than 1.2 µs; the latter recognizes additional SHDSL signal processing. Although these values may seem small, they increase the latency of many other nodes in any end-to-end digital connection. Speech is particularly sensitive to delay when an echo is present. Delayed echo makes conversation difficult and annoying when the round-trip delay exceeds about 8ms.

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Video Communications Technologies I: Narrowband Transmissions

LF Chang, TR Hsing, envisual communication manual, 1995

13.2.5 High bit rate digital subscriber line

With the advancement in high-speed digital signal processing and VLSI technology, we can now usehigh bit rate digital subscriber line(HDSL) technology [7] to transmit high-speed digital data over the existing copper loop system. HDSL is a scheme that uses two pairs to provide bidirectional transport (DS1) at 1.544 Mb/s to cover the entire CSA area. To reduce deficiencies caused by NEXT and cable losses, a "full duplex" architecture was adopted. This architecture requires two pairs of copper wires (as in the case of Digital Loop Carrier (T1) lines). Using echo cancellation, each pair can transmit 784 kb/s in full duplex transmission. This system was originally intended as a rapid deployment vehicle for enterprise DS1 services. Given the high demand for 1.5 Mb/s in the commercial space, it is expected that a system that offers capacity equivalent to T1 technology, but uses existing wire pairs without special engineering, will fill an important market need. Since T1 repeaters are avoided, cost savings are realized. The client interface is the same as the traditional T1.

One of the main goals of HDSL technology is to provide a seamless replacement for a T1 line, and several phone companies are conducting field trials. HDSL is envisioned as a transitional technology that will support the ubiquitous availability of DS1 services as fiber penetration accelerates.

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500 ksps and 600 ksps ADCs meet the needs of high-speed applications

Kevin R. Hoskins, emAnalog Circuit Design, Volume Three, 2015

important applications

The features of the LTC1278 benefit at least four distinct application areas: telecommunications, communications, PC DAQ cards, and high-speed multiplexed DAQ.

Telecommunication digital data transmission applications such asHigh bit rate digital subscriber line(HDSL) with its fast T1 data rate benefits from the low power dissipation of the LTC1278, as these telecommunications systems normally derive their power from the telephone line. While the LTC1278's 500 ksps conversion rate easily handles T1 data rates, the LTC1279's 600 ksps conversion rate is ideal for HDSL's faster E1 data rates. In addition, these applications use noise and echo cancellation, which require excellent sample-and-hold dynamic performance from the ADC. The LTC1278 meets this requirement as demonstrated by the excellent dynamic performance of the device shown in theFigure 357.1.

Communications applications also benefit from the high input bandwidth and downsampling capability of the LTC1278/LTC1279. The app is displayedFigure 357.2uses the LTC1278 to downsample (to 227.5 ksps) an IF frequency. 455 kHz. amplitude modulated by a 5 kHz sine wave.Figuras 357.3A e 357.3Beach shows the IF of 455 kHz. The carrier and recovered 5 kHz sine wave resulting from a 12-bit DAC reconstruction.Figure 357.2also shows that this simple setup only requires 0.43 inches using surface mount devices²real estate circuit board.

High Bit Rate Digital Subscriber Line - Overview (5)

High Bit Rate Digital Subscriber Line - Overview (6)

PC data acquisition cards are another wide application area. The LTC1278's high sample rate, simple and comprehensive setup, small package design and low cost make this converter ideal for these applications. In addition, the LTC1278's internal synchronized conversion clock minimizes conversion noise that occurs when the conversion clock and sample command are out of sync. This internal clock and sample synchronization overcomes what can be a cumbersome task in PC environments.

High-speed, single-channel multiplexed data acquisition systems benefit from the dynamic conversion performance of the LTC1278/LTC1279. Conversion times of 1.6 µs and 1.4 µs and S/H acquisition times of 200 ns and 180 ns allow the LTC1278/LTC1279 to convert at 500 ksps and 600 ksps, respectively.Figure 357.4shows a 500 ksps 8-channel data acquisition system. The high input impedance of the LTC1278 eliminates the need for a buffer amplifier between the multiplexer output and the ADC input.

High Bit Rate Digital Subscriber Line - Overview (7)

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Transport solutions for optically enhanced networks

Werner Weiershausen, Malte Schneiders, enOptically Enhanced WDM Networks, 2011

11.2.1.1 Access Networks

The current private access networks provide fixed and mobile telecommunications services, the latter dominating the total traffic capacity. DifferentDigital subscriber line (DSL) technologies, such as asymmetric DSL (ADSL) and very high bit rate DSL (VDSL), require a maximum data traffic of up to 50 Mbit/s per subscriber. DSL backhaul is already done with FTTC (Fiber to the Cabinet) solutions, where the cabinets are placed on the streets of urban and suburban regions. In addition, Fiber to the Building (FTTB) and Fiber to the Home (FTTH) deployments have begun in Europe and will provide further bandwidth growth fueled by future consumer broadband services.

As operators move from DSL to FTTB/H, they will look to reduce operating costs, which is particularly important for incumbent European operators. As a result, many branches will eventually close. Typical scenarios show a trend of closing 90% of sites, which means that only 10% of active sites will remain.

The long distance that must be bridged between FTTx access nodes and the remaining 10% of active exchanges for backhaul creates serious problems for network operators when using passive optical network (PON) solutions that include gigabit PON (GPON) and Ethernet -Use PON (EPON ) with tree topology. The problem is a combination of long distances of more than 40 km and a high PON split rate to cover a large area with many houses and buildings scattered around small central offices. Furthermore, in combination with a high bandwidth requirement, large distances and high split ratios cannot be managed with classic GPON/EPON technologies.

Amplifier extenders can expand the power budget of PON networks with high splitter and fiber transmission losses. These extenders are placed in semi-active locations using simple outdoor enclosures with limited space, without air conditioning or staff. In this way, the desired reduction in operating costs can be achieved. But even PON tree networks based on a single wavelength will not be able to take on the entire problem space. An alternative is color systems such as WDM-PON or hybrid systems such as Time Division Multiple Access (TDMA) PON color channels in a WDM system. These WDM-PON systems must be amplified by optical amplifiers (EDFA). Usually the EDFA is followed by a WDM splitter, e.g. a demultiplexer (DEMUX). It is important that both DEMUX and EDFA can be placed in outdoor cabinets without air conditioning. You must be very tolerant of temperature changes; hence, athermally arrayed (AWG) waveguide grid filters are used for DEMUX filters.

In addition to star and tree topology for WDM-PON, ring topology is also possible. WDM rings with fixed optical add-drop multiplexers (OADM, Fixed OADM [FOADM], simple filters) can be used to collect traffic from different access sides and forward it to a common hub node (Hub & Spoke for the Metro network) to put . The benefit is efficient use of the existing fiber plant and these rings allow for easy 1+1 or 1:1 protection using both ring directions. Since the transport costs of transit traffic through OADM nodes are relatively low, this is an interesting alternative for stars and trees. To support the ring loss budget, optical amplifiers (EDFA) must be used for this architecture. They can be placed in the multiplexer/demultiplexer/OADM locations.

Inexpensive EDFAs are preferred in relatively small access rings with comparatively little signal-to-noise ratio (OSNR) degradation. The very cheap passive Coarse Wavelength Division Multiplexing (CWDM) technology is not suitable for the application because the distances for purely passive rings are too long. However, this argument applies to the scenario with the very small number of exchanges mentioned above.

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Distributed and cooperative systems FBMC

Martin Haardt, ... Eleftherios Cofidis, umOrthogonal waveforms and filter banks for future communication systems, 2017

(Video) Methods Used To Achieve High Data Rates With DSL Systems - Presentation

16.3.2 Multi-user channel estimation based on SNR

16.3.2.1 Introduction

Preamble-based channel estimation was discussed in Section16.3.1. It is based on the assumption that the channels remain constant over the duration of the packet. Depending on the mobility in the system and the length of the packets, some additional tuning of the channel estimate may be required in many scenarios. Most estimation methods for this purpose in multicarrier communication systems are based on pilots.[20]. However, in the case of FBMC/OQAM, the complicated structure of interference that occurs in the receiver makes the use of pilots a bit difficult and requires additional techniques such as pair of pilots (POP) or auxiliary pilots.[23]. All these techniques are presented in more detail in the chapter11.

In this section, we present another estimation method that no longer uses pilots. It is suitable for channels that change slowly in time and has the advantage of being applicable in a distributed scenario. It is based on applying various well-designed perturbations of the transmitted signals. Changes in SNRs observed at different receivers caused by this interference are measured and relayed to the base stations. Information from various interferences is collected at the base station and used to perform channel estimation periodically during data transmission. With this method, receivers simply estimate their SNR in the normal way and need not be aware of the generated interference. It has the advantage of requiring little overhead (only the SNRs need to be fed back). Interference, on the other hand, affects normal data transmission and must be kept small enough to allow continuous transmission. Similar methods have already been presented in connection with very high bitrate digital subscriber lines (VDSL) with discrete multitone transmission (DMT).[24]o for multi-cell OFDM systems[25]. This section shows how the method can be applied to the more complicated case of FBMC/OQAM with different configurations.

16.3.2.2 System model and pre-coding

We consider a distributed MIMO environment using FBMC/OQAM modulation. The model considered is similar to the one in the previous section and is shown inFigure 16.5. However, for simplicity, the model here is restricted to the case where the number of base stations equals the number of users. There isnorteBase stations (transmitters) on the system andnorteEach node is equipped with a single antenna (however, the method can easily be generalized to multiple antennas). Base stations cooperatively transmit their signals (similar to a single transmitter with multiple antennas) to transmitnorteindependent information flows to thenorteIt is considered as a linear precoder. It is assumed that the channel is very selective and that the number of subcarriers is sufficient for the channel to be considered flat within each subcarrier. Therefore, interference between subcarriers is negligible. All operations can be applied independently per subcarrier, so thatin this section only a certain subcarrier m is considered. The channel is also assumed to change slowly with time, so it can be assumed to be constant over the duration of several measurements. This is a pretty strong assumption that limits the use of this method to low mobility systems.

The actual information symbols to be conveyed to the different users $EU = 0, 1, \dots, norte - 1$ on the subcarrier of interestSubwayImmediatelynorteare marked with $D_{Subway, norte}^{EU}$ . They are grouped into a vector. $D_{Subway, norte} = {[\begin{matrix} D_{Subway, norte}^{0} & \dots & D_{Subway, norte}^{norte - 1} \end{matrix}]}^{T}$ . The variance of the symbols is denoted by ${Page}_{D}^{2}$ and is considered the same for all symbols. The information is pre-coded by different base stations and sent over the channel. Receivers only have access to symbols received on their own antenna. It is assumed that each receiver (independently) applies a zero-strength equalizer per subcarrier. The array of interesting channelsHcorresponds to the precoding combination, the channel $H_{Subway}$ on the subcarrier of interest and on the set of independent equalizers per user. this is a square $norte \times norte$ Headquarters. The method presented here aims to estimate this matrix. For the remainder of this section, it will be referred to as the blended channel matrix. It is interesting to note that in a tracking scenario (i.e. when some estimates have already been made based on the preamble), it can be assumed that the current precoding provides adequate user-to-user interference rejection andHis close to the identity matrix. Considering the particular interference structure resulting from FBMC/OQAM modulation and assuming that the channel is flat within each subcarrier, the general transmission model can be written as[13,26]

(16.12) ${\bar{D}}_{Subway, norte} = H D_{Subway, norte} + J H \sum_{{Subway}^{'} = Subway - 1}^{Subway + 1} \sum_{{norte}^{'} = norte - 3}^{norte + 3} T_{Subway, {Subway}^{'}} (norte - {norte}^{'}) D_{{Subway}^{'}, {norte}^{'}} + {\bar{Subway}}_{Subway, norte},$

Wo ${\bar{D}}_{Subway, norte}$ stacks the equalizer outputs of the different users, where $C_{Subway, {Subway}^{'}}^{norte, {norte}^{'}} = J T_{Subway, {Subway}^{'}} (norte - {norte}^{'})$ denotes the transmultiplexer response of the filterbank, as in chapter11, responsible for the complex interference that occurs in the receiver by FBMC/OQAM modulation, and where ${\bar{Subway}}_{Subway, norte}$ denotes the vector of noise samples. The variation of noise samples for the userEUis marked with ${Page}_{Subway, EU}^{2}$ .

16.3.2.3 Estimation method based on small perturbations

To illustrate, consider estimating the combined coefficients of the index channel matrix $(EU, norte)$ , that is, the estimate of $H_{EU norte}$ for a specific userEU(the element $(EU, J)$ HeadquartersHis described as $H_{EU J}$ ). The basic principle behind this method is to add a small amount of interrupt to the victim user's icons.EUuser data flownorte. The impact of this small disturbance on the user's SNREUobserved and from the corresponding changes in SNR, the combined channel matrix coefficients of interest can be estimated.

First, the SNR is calculated during normal transmission with all users active (including the usernorte).⁵The SNR observed at the receiverEUduring normal transmission is given through

(16.13) $\frac{1}{{SNR}_{EU, 0}} = \sum_{of \neq EU} H_{EU of, R}^{2} + \frac{{Page}_{Subway, EU}^{2}}{{Page}_{D}^{2}} + \sum_{{Subway}^{'}} \sum_{{norte}^{'}} \sum_{of} T_{Subway, {Subway}^{'}}^{2} (norte - {norte}^{'}) H_{EU of, EU}^{2},$

Wo $H_{EU of, R} = ℜ {H_{EU of}}$ j $H_{EU of, EU} = ℑ {H_{EU of}}$ .

After this first SNR measurement, a second situation is considered in which the usual data symbol is transmitted instead. $D_{Subway, norte}^{EU}$ for the userEU, a noise is added proportionally to user symbolsnorte. The transmitted symbols are now

(16.14) $D_{Subway, norte}^{EU} (1) = D_{Subway, norte}^{EU} + ϵ_{EU norte} D_{Subway, norte}^{norte},$

where the coefficients $ϵ_{EU norte}$ they are real coefficients with small amplitude so as not to disturb the normal transmission too much. The new SNR for the userEUcan be approximated

(16.15) $\begin{matrix} \frac{1}{{SNR}_{EU, 1}} = & {[H_{EU norte, R} + ϵ_{EU norte}]}^{2} + \sum_{of \neq EU; of \neq norte} H_{EU of, R}^{2} + \frac{{Page}_{Subway, EU}^{2}}{{Page}_{D}^{2}} \\ + \sum_{{Subway}^{'}} \sum_{{norte}^{'}} \sum_{of} T_{Subway, {Subway}^{'}}^{2} (norte - {norte}^{'}) H_{EU of, EU}^{2} . \end{matrix}$

As can be seen, the interference affects the SNR by modifying the apparent combined coefficient $H_{EU norte}$ . From the receiver's point of view and because of the failure, everything happens as if the coefficient had changed to the new value $H_{EU norte} + ϵ_{EU norte}$ . All other coefficients are unaffected.

A third SNR measurement is needed to obtain the full normalized matrix coefficient (real and imaginary parts) using a second perturbation. In this third situation, slightly modified noise is added to the symbols. The new transmitted symbols are

(16.16) $D_{Subway, norte}^{EU} (2) = D_{Subway, norte}^{EU} + ϵ_{EU norte} T_{Subway, Subway} (1) D_{Subway, norte - 1}^{norte} .$

Observe that $D_{Subway, norte - 1}^{norte}$ is used here instead $D_{Subway, norte}^{norte}$ as well as an additional coefficient $T_{Subway, Subway} (1)$ , the purpose of which we will see below. In this case, it is easy to see that everything proceeds as if the combined channel coefficient $H_{EU norte}$ is replaced by $H_{EU norte} + J ϵ_{EU norte}$ . The SNR in the second perturbation is satisfactory

(16.17) $\begin{matrix} \frac{1}{{SNR}_{EU, 2}} = & {[H_{EU norte, EU} + ϵ_{EU norte}]}^{2} T_{Subway, Subway}^{2} (1) + \sum_{of \neq EU} H_{EU of, R}^{2} + \frac{{Page}_{Subway, EU}^{2}}{{Page}_{D}^{2}} \\ + \underset{({Subway}^{'}, {norte}^{'}, of) \neq (Subway, norte - 1, norte)}{\sum \sum \sum} T_{Subway, {Subway}^{'}}^{2} (norte - {norte}^{'}) H_{EU of, EU}^{2} . \end{matrix}$

Based on these three measurements, it is now possible to obtain the combined channel coefficients $H_{EU norte, R}$ j $H_{EU norte, EU}$ (real part and imaginary part). After some calculations, the following estimators are obtained:

(16.18) ${\hat{H}}_{EU norte, R} = \frac{1}{2 ϵ_{EU norte}} (\frac{1}{{SNR}_{EU, 1}} - \frac{1}{{SNR}_{EU, 0}}) - ϵ_{EU norte} / 2 .$

Similar,

(16.19) ${\hat{H}}_{EU norte, EU} = \frac{1}{2 ϵ_{EU norte} T_{Subway, Subway}^{2} (1)} (\frac{1}{{SNR}_{EU, 2}} - \frac{1}{{SNR}_{EU, 0}}) - ϵ_{EU norte} / 2 .$

These equations provide an estimation method for the real and imaginary parts of the combined channel matrix coefficient. It also applies when other users are present, as long as their power remains constant during all three SNR measurements. It only requires the three SNR measurements described above for a value of $ϵ_{EU norte}$ , which can be chosen arbitrarily. To make the estimate as accurate as possible, $ϵ_{EU norte}$ should be chosen as large as possible so that a significant influence on the SNR can be measured. On the other hand, if $ϵ_{EU norte}$ is too large, there is a risk that the SNR will be excessively reduced and the normal transmission of data symbols will be impeded.

16.3.2.4 Simulation Results

To illustrate the power of the method, we present some simulation results in this section. A system with five users and five base stations is considered and, for simplicity, only a given subcarrier is examined. Different situations of noise and interference power (corresponding to different accuracies or different levels of channel tracking) are studied. A large number of simulations (5000) are performed for each situation. The channel matrix is randomly generated for each simulation according to a log normal model and satisfies noise and interference constraints. disturbance coefficients $ϵ_{EU J}$ are selected according to the rule developed in[27]. The variance of channel coefficient estimates is calculated by averaging all simulations. Rather than plotting the variance estimate itself, the results are plotted with the most significant value of the resulting signal-to-interference ratio (SIR). Offersan assessment of how well the precoder obtained reduces interference between users in terms of signal strength.Figure 16.9shows the SIR obtained based on the number of blocks $k_{mi}$ used for each measurement, expressed as the total time spent (in the number of FBMC symbols). Three situations of noise and interference are presented in which interference between users predominates. An additional situation (denoted Add N) is presented where additive noise is dominant. Also shown in circles is the predicted performance achieved with the results shown in[27]. As can be seen, the proposed method can improve the channel estimation and therefore reduce the residual interference between users by several dB. However, this requires sufficient time and therefore a time-slow channel.

High Bit Rate Digital Subscriber Line - Overview (8)

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(Video) Very-high-bit-rate digital subscriber line

A survey of smart metering and smart grid communications

Yasin Kabalci, sou meistenComments on renewable and sustainable energy, 2016

4 communication technologies used in smart grid

One of the most important achievements of the smart grid is the AMI system, which is used to measure, collect and analyze data on the energy consumption and energy quality of each consumer. Each SM with AMI infrastructure implies a facility to communicate with on-demand meters[56]. Two-way communication is performed between the utility provider and the consumer to enhance the provider's maintenance, demand management, and planning capabilities.

Figure 5illustrates a block diagram of the wired and wireless communication architecture used in the smart grid. Data management is one of the very important tasks in smart grid as measured billing data plays an important role. The middle part ofFigure 5it consists of a measurement data management system (MDMS) that handles data storage and processing tasks. The components of an MDMS are the Outage Management System (OMS), the Geographical Information System (GIS), the Consumer Information System (CIS) and the DMS, with each system dedicated to interoperating with the communication and sharing management systems.[56].

High Bit Rate Digital Subscriber Line - Overview (9)

The OMS system requires data to be collected when power quality or related indicators are exceptional for a customer. Regular measurements obtained at high frequencies are unrelated to the operating characteristics of the OMS and are filtered out in the signal processing steps. This subsystem allows MDMS to detect any abnormal situation in order to intervene immediately. GIS and CIS systems need to collect data such as utility location, consumption rates and billing information about SM and the consumer. The DMS can be operated as a plant-wide monitor, observing power quality and load demand rates for management and forecasting. Central operations center can be extended to multiple distributed operations centers planned in the same MDMS framework[56].

The communication between the operations center and the SM can be in different protocols using two ways, for example B. wired and/or wireless applied. Wired communication is done through transmission lines, and the widely known method is PLC. The central idea is based on the use of transmission and distribution lines as a means of communication, thus addressing any additional communication channel requirements. While aging feedline losses are the main disadvantage of this method, the transmission channel reduces overall installation costs by eliminating additional system requirements.[10,51]. On the other hand, PLC applications offer data rates of up to 200 Mbit/s for a single-phase system. You can also use different wireless communication methods based on the IEEE 802.22 Wireless Regional Area Network (WRAN) protocol or the IEEE 802.15.4 Wireless Personal Area Network (WPAN) protocol. There are numerous studies on wireless smart grids in the literature, some of which are presented in the next section.[65–71]. Digital communication methods are significantly used to improve wireless networks including ZigBee, Wi-Fi and Bluetooth to solve the lack of PLCs in high frequency applications.

The smart grid communication architecture is defined by the IEEE 2030-2011 standard, which is important to understand applications and infrastructures in a hierarchical arrangement.[70]. The standard aims to build consensus on the many confusing descriptions by clearly specifying a logical structure for smart grid networks spanning three subnets. The first networks related to customer properties are called private networks, including HANs, Industrial Area Network (IAN) and Building Area Network (BAN). The second network in the distribution layer is called the WAN and consists of the Neighbor Area Network (NAN) and the Field Area Network (FAN). These networks are equipped with various control and monitoring systems such as B. remote terminal units, AMIs and PMUs to manage the various functions.[69,70]. The last type of network described by the standard is the core network to serve sections such as the generation and transmission layers. The core network includes broadband communication architectures such as Local Area Network (LAN), Virtual Private Network (VPN), Voice over Internet Protocol (VoIP) and GIS.[71–75]. Smart grid communication technologies are described as narrowband and broadband in terms of bandwidth characteristics. The following sections are devoted to a brief presentation of these technologies.

4.1 Wired communication technologies

Wired communication, mostly preferred by service providers, is used to carry out data communication through power lines, as the name suggests.[66,69,71]. The most important advantage of wired communication is its reliability and interference immunity. While PLC is the most common wired communication technology, others, such as optical fiber and digital subscriber line (DSL), are becoming pervasive on telephone lines. Digital communication methods can support high-speed data transmission between 10 Mbps and 10 Gbps over DSL, or between 155 Mbps and 160 Gbps over coaxial and fiber optic cables.[66,71,76].

The PLC faces several engineering challenges due to the unexpected propagation characteristics of transmission and distribution lines. These spurious effects and interference are usually concentrated in electromagnetic environments such as transformers.[71,77,78]. Although various methods have been implemented to eliminate spurious effects on wired lines, there are two main PLC technologies that operate at different bandwidths.[71]These are narrowband PLC (NB-PLC) and wideband PLC (BB-PLC). The NB infrastructure was proposed in its early stages for transmissions ranging from a few bps to a few kbps. The resulting bandwidths are further scaled from 1 bps to 10 kbps and up to 500 kbps, operating at precisely 500 kHz transmission frequencies. The NB-PLC can be used on low voltage and high voltage lines with a transmission length of up to 150 km or more. Another PLC infrastructure, BB-PLC, works with a significantly higher bandwidth of up to 200 Mbit/s and higher frequency bands from 2 MHz to 30 MHz.[71,73]. The success of the NB-PLC spurred the progress of the BB-PLC, which was specifically designed for Internet services and HAN applications. In 1997, major Internet applications focused on Internet access and service delivery by PLCs were observed in Europe. However, the results frustrated the idea of a PLC-based Internet access. Therefore, interest shifted to industrial communications and home applications in the early 2000s, accelerated by various industry alliances such as the HomePlug Powerline Alliance (HomePlug), Universal Powerline Association (UPA), High Definition PLC (HD-PLC) Alliance, and HomeGrid. Forum[73]. Several standards for organizing implementations have been described in the last decade, such as: B. TIA-1113, ITU-T G.hn, IEEE 1901 FFT-OFDM and IEEE 1901 Wavelet-OFDM.[73,78–80]. While the various products have been enhanced to operate at physical layer (PHY) bandwidths of 14 Mbit/s (HomePlug 1.0), then 85 Mbit/s (HomePlug Turbo) and then 200 Mbit/s (HomePlug AV, HD- PLC, UPA ), none of them are able to work together. On the other hand, BB-PLC, which can be described as an addition to the home Wi-Fi network, has yet to capture any significant market share.[73]. Other wired communication systems besides PLC consist of optical methods and DSL communication, which offer higher data rates compared to PLC. The main advantages of optical communication are its ability to transmit Gbps data packets over several kilometers and its resistance to electromagnetic interference.[71,73]. These properties make it suitable for high voltage lines. In addition, a special type of cable called an optical power ground wire allows high data rates to be transmitted over long distances.

Another wired communication technology used in the smart grid is DSL, which allows digital data to be transmitted over telephone lines. This infrastructure thus avoids additional costs of installing the means of communication, since the exchanges are connected to the control centres. The types of DSL technologies are asymmetrical DSL (ADSL) with a data download speed of 8 Mbit/s, ADSL2+ with a maximum download speed of 24 Mbit/s and very high bit rate DSL (VDSL or VHDSL) with data transmission of up to 52 Mbit/s over copper cables.[71]. The standards, data rates, advantages and disadvantages of wired and wireless communication technologies are presented inTable 1.

Table 1. Complete list of communication technologies used in the smart grid.

Technology	Standards	data speed	distance	Rot	Advantage	Disadvantage
wired technologies
ANONYMOUS SOCIETY	● NOTA-SPS: ISO/IEC 14908-3,14543-3-5, CEA-600.31, IEC61334-3-1, IEC 61334-5 (FSK) ● BB-PLC: TIA-1113 (HomePlug 1.0), IEEE 1901, ITU-T G.hn (G.9960/G.9961) ● BB-SPS: HomePlug AV/Ext., PHY, HD-SPS	● NB-PLC: 1-10 kbps for low PHY data rate, 10-500 kbps for high PHY data rate ● BB-PLC: 1-10 Mbit/s (up to 200 Mbit/s over very short distances)	● NB-PLC: 150km or more ● BB-PLC: ca. 1,5km	● NB-PLC: NAN, FAN, ONE, Großformat ● BB-PLC: HAN, BAN, IAN, small-scale AMI	● Extensive already configured communication infrastructure ● Ability to physically separate from other networks ● Lower operating and maintenance costs	● Increased signal loss and channel interference ● Interference from electrical devices and other electromagnetic interference ● Difficult to transmit higher bitrates ● complex routing
fiberglass	● AON (IEEE 802.3ah) ● BPON (UIT-T G.983) ● GPON (UIT-T G.984) ● EPON (IEEE 802.3ah)	● AON: 100 Mbps up/down ● BPON: 155–622 Mbit/s ● GPON: 155-2448 Mbps up, 1.244-2.448 Gbps down ● EPON: 1 Gbit/s	● AON: bis 10 km ● BPON: up to 20-60km ● EPON: up to 20 km	● BLASS	● remote communication ● ultra high bandwidth ● Robust against electromagnetic and radio interference	● Higher setup costs (PONs are lower than AONs) ● Edge device costs ● Not suitable for measurement and update applications
ADSL	● DE G.991.1 (HDSL) ● G.992.1 OUTPUT (ADSL), G.992.3 OUTPUT (ADSL2), G.992.5 OUTPUT (ADSL2+) ● G.993.1 OUTPUT (VDSL), G.993.1 OUTPUT (VDSL2)	● ADSL: 8 Mbit/s Download/1,3 Mbit/s Upload ● ADSL2: 12 Mbit/s down/3.5 Mbit/s up ● ADSL2+: 24 Mbps down / 3.3 Mbps up ● VDSL: 52–85 Mbit/s down/16–85 Mbit/s up ● VDSL2: até 200 Mbit/s up/down	● DSL: up to 5 km ● ADSL2: has a distance of 7 km ● ADSL2+: has a distance of 7 km ● VDSL: up to 1.2 km ● VDSL2: 300 m–1,5 km	● FRIENDS, IN, FANS	● Extensive already configured communication infrastructure ● The most used broadband	● Communications operators can charge utilities high prices for the use of their networks ● Not suitable for network backhaul (fern)
wireless technologies
WPAN	● IEEE 802.15.4 ● ZigBee, ZigBee Pro, ISA 100.11a (IEEE 802.15.4)	● IEEE 802.15.4: 256 kbit/s	● ZigBee: Hasta 100m ● ZigBee Pro: up to 1600m	● HAN, BAN, IAN, NAN, FAN, AMI	● Very low power consumption, low cost implementation ● Fully compatible with IPv6 based networks	● low bandwidth ● Limitations when building large networks
W-lan	● IEEE 802.11e ● IEEE 802.11n ● IEEE 802.11s ● IEEE 802.11p (ONDA)	● IEEE 802.11e/s: até 54 Mbps ● IEEE 802.11n: até 600 Mbps	● IEEE 802.11e/s/n: höchstens 300 m ● IEEE 802.11p: bis 1 km	● HAN, BAN, IAN, NAN, FAN, AMI	● Inexpensive network implementations ● cheapest devices ● High flexibility, suitable for various applications	● High Interference Spectrum ● Too high power consumption for many smart grid devices ● Simple QoS support
WiMAX	● IEEE 802.16 (fixed and mobile wireless broadband access) ● IEEE 802.16j (Relais-Multisalto) ● IEEE 802.16m (interface aérea)	● 802.16: 128 Mbps down/28 Mbps up ● 802.16m: 100Mbps for mobile, 1Gbps for landline users	● IEEE 802.16: 0–10km ● IEEE 802.16m: 0–5 (optional), 5–30 acceptable, 30–100 km low	● NAN, FAN, WAN, AMI	● Supports large concurrent user groups, distances greater than Wi-Fi ● A connection-oriented control of channel bandwidth ● More demanding QoS than 802.11e.	● Managing complex networks is ● Edge device costs ● Demand for Licensed Spectrum
G/M	● 2G-TDM, IS95 ● 2,5G HSCSD, GPRS ● UMTS-3G (HSPA, HSPA+) ● 3.5G HSPA, CDMA-EVDO ● 4G LTE, LTE-Advanced	● 2G: 14,4 kbit/s ● 2,5 G: 144 kbps ● HSPA: 14.4 Mbit/s down/5.75 Mbit/s up ● HSPA+: 84 Mbit/s down/22 Mbit/s up ● LTE: 326 Mbit/s down/86 Mbit/s up ● LTE-Advanced: 1 Gbit/s/500 Mbit/s	● HSPA+: 0–5km ● LTE-Advanced: ideal 0-5 km, acceptable 5-30, 30-100 km (reduced performance)	● HAN, BAN, IAN, NAN, FAN, AMI	● Supports millions of devices ● Low power consumption of end devices ● High flexibility, suitable for various applications, ● open industry standards	● High prices for using service provider networks ● Higher costs due to licensed spectrum
Satellite	● LEO: Iridium, Globalstar, ● MEO: New ICO ● Geo: Inmarsat, BGAN, Swift, MPDS	● Irídio: 2,4–28 kbps ● Inmarsat-B: 9,6 bis 128 kbps ● BGAN: 1 Mbps speed	● 100–6000 km	● WAN, AMI	● Fern ● extremely reliable	● Edge device costs ● high latency

4.2 Wireless communication technologies

The National Institute of Standards and Technology (NIST) has proposed wireless technologies as important networks for GS. Demand management, the main characteristic for delivering SG efficiency and reliability, is based on the selection of the most appropriate communication technologies to streamline management. The main criteria for selecting the exact technology are related to economic and technological feasibility.[81-83]. Wireless communication networks are one of the most researched topics in power systems involved in the SG concept. While wireless networks have brought many advantages in terms of deployment and range, the main shortcoming is their vulnerability to limited bandwidth and interference.[81].

Wireless networking consists of hierarchical mesh networks that use wireless LANs to interact with electrical devices. The most suitable AMI infrastructures are NANs and HANs for wireless deployment due to their low installation costs.[81,82]. Internet-based communication infrastructures and Data Management Points (DMPs) can be installed wired or wireless, with communication between NAN and DMP covering several kilometers. Each DMP can connect and manage hundreds of SMs, allowing you to configure a large coverage area with mesh networks or broadcast DMPs. Innovative studies on SG applications are based on highly scalable and pervasive communication networks that can be easily built using Wireless Sensor Networks (WSN). Furthermore, WSNs must provide reliable infrastructure reducing latency according to demand requirements.[82,83]. OpenSG latency requirements are less than 1s for NANs, which is easier compared to high-bandwidth commercial communications. HANs configured to perform power management and demand planning have a smaller footprint compared to NANs. HANs generally allow for less than 5 seconds of latency, which is also much simpler compared to NANs.[82].

The excellent communication technologies used in NANs are based on the Global Interoperability for Microwave Access (WiMAX), Universal Mobile Telecommunications System (UMTS)/Long Term Evolution (LTE) and IEEE 802.22 standards. In addition, Wi-Fi and WPAN technologies based on IEEE 802.11 and IEEE 802.15 are also used in wireless SGs. WiMAX, which is an implementation of the IEEE 802.16 standard for metropolitan area networks (MANs), is the key technology to provide connectivity between DMP and SM. WiMAX uses Orthogonal Frequency Division Multiple Access (OFDMA), the multi-user adaptation of the regular OFDM digital modulation scheme. The multiuser structure is achieved in OFDMA by organizing the subsets of different subcarriers into individual consumers, which allows simultaneous transmission of data from a large group of consumers at low data rates.[82,84-86]. WiMAX's multi-user subcarrier-based structure eliminates interference between consumer data and increases the spectral efficiency of the entire system. Although the structure of WiMAX is not very complicated compared to cellular standards, it is not widely used as a wireless platform in SG applications. However, this situation does not limit your chances against competing platforms due to your DMP interactions.[82].

The IEEE 802.15.4 standard, ie WPAN, is the benchmark that defines the PHY layer for low data rate, low power consumption and cost-effective networking. The WPAN base PHY layer provides a data rate of 256 kbps in the coverage area from 10 m to 1600 m in star topology for single-hop, cluster tree and mesh topology for multi-hop. In each type of topology there is a PAN coordinator that manages the entire network. Furthermore, mesh and tree topologies contain additional router nodes as an interface between the coordinator and devices to establish multi-hop connections. Several industry standards are based on the IEEE 802.15.4 standard for monitoring and control applications. The most prominent standards in this classification are ISA 100.11a, Wireless-HART and ZigBee, which among others is the most prominent as they are used in industrial control processes. However, ZigBee is widely used in industrial and commercial applications due to its advanced network management features.[71,82].

Cellular technologies such as UMTS and LTE, based on the Global System for Mobile Communications (GSM), offer multiple options for NAN coverage. The main advantage of GSM-based technologies is the larger coverage areas compared to other wireless networks. Evaluation of cellular networks is very fast and the latest technologies support wider data bands. UMTS, the most popular standard in 3G technology, provides data communication at up to 168 Mbit/s on the downlink and up to 22 Mbit/s on the uplink. The latest cellular technology is 4G, based on LTE and LTE Advanced standards, which extend UMTS capabilities.

It offers higher bandwidth and a wider frequency band, facilitates interaction between different networks, better macrocell to femtocell network support, and advanced mobile network features. Although satellites allow for wireless communications with varying bandwidth and latency, it is a very expensive technology in itself.

The satellites are in orbits known as Low Earth Orbits (LEO), Medium Earth Orbits (MEO) and Geostationary Earth Orbits (GEO) to provide communications for networks installed in rural or far-reaching locations where they are outside cellular coverage. . . . It is anticipated that the lower cost of smaller satellite stations could be an opportunity to integrate this technology into SG applications and AMI networks.[71,82]. Wireless network of multimedia sensors and actuators to be introduced[84]It is intended to transmit image and voice data of various physical structure information such as temperature, humidity and similar telemetry data.

A new wireless technology that aims to correct insufficient frequencies is Cognitive Radio (CR). Smart grid users are defined in CR applications as primary and secondary users, which allows assigning the communication channel to any user who needs it at the precise moment.[87]. As CR can reduce the need for licensed spectrum, this topic has attracted more attention to this technology. On the other hand, CR promoted the high radio bandwidths needed to deliver large volumes of multimedia data, including power monitoring and control units.[88]. SG security and traffic management issues are explored extensively in relation to both wired and wireless networks. Cybersecurity threats to communication systems are divided into four types related to availability, protection, integrity and authenticity.[89,90]. Security concepts considered in SG applications are presented in the following sections.

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(Video) Cable vs DSL vs Fiber Internet Explained

FAQs

What is very high bit rate digital subscriber line? ›

VDSL or VHDSL (Very High Bitrate DSL) is a DSL technology providing faster data movement. This works over a single flat untwisted or twisted pair of copper wires. These fast speeds mean that VDSL can move data for digital television, as well as telephone services (Voice over IP) and Internet.

What does high bit rate digital subscriber line HDSL uses two twisted pairs to achieve? ›

HDSL uses two twisted pairs (one pair for each direction) to achieve full-duplex transmission.

What is the most common form of Digital Subscriber Line with much higher download speed? ›

Most types of DSL service are asymmetric, or ADSL. Typically, ADSL offers higher download speeds than upload speeds, which is usually not a disadvantage because most households download more data from the internet than they upload. Symmetric DSL maintains equal data rates for both uploads and downloads.

Is high bit rate good? ›

A higher bitrate means better video data, which allows for visual effects artists to more precisely eliminate that color green, and that color green only. When they do, they can replace it with visual effects that look much more convincing because they're built on a good foundation of digital visual information.

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Is higher bit rate always better? ›

As one might expect, a higher bitrate improves the quality of a video. Higher bitrate correlates with higher image quality, while lower bitrate results in a lower quality. Twitch streamers want to strive for a higher bitrate, as it means that their stream's video quality will be better.

What is the advantage of HDSL? ›

HDSL eliminates engineering time and reduces the cost and provisioning time associated with conditioning T-1 lines. Since HEIST automatically adjusts to gauge changes and bridged taps, it eliminates the rearrangement of local loop facilities.

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How does HDSL work? ›

How Does DSL Work? DSL utilizes old copper telephone lines to transfer digital data, including internet downloads and uploads and VoIP calls, together with conventional phone signals. It runs at different frequencies than phone signals, but dial-up internet inhibits phone signals from utilizing the connection.

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What is the meaning of HDSL? ›

A technology for high-speed network or Internet access over voice lines. There are various types, including asymmetric DSL (ADSL), high-bit-rate DSL (HDSL), symmetric DSL (SDSL) and very-high-bit-rate DSL (VDSL). The whole group is sometimes referred to as “xDSL.”

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What are the two types of digital subscriber line? ›

Common types of DSL are symmetric digital subscriber line (SDSL, with matching upload and download speeds); asymmetric digital subscriber line (ADSL), featuring faster download speeds than upload speeds; and very high-rate digital subscriber line (VDSL, featuring much faster asymmetric speeds).

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How does digital subscriber line work? ›

DSL (Digital Subscriber Line) is a modem technology that uses existing telephone lines to transport high-bandwidth data, such as multimedia and video, to service subscribers. DSL provides dedicated, point-to-point, public network access.

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What is the maximum distance for DSL? ›

The maximum distance from a DSL modem to a DSL access multiplexer (DSLAM) is 18,000 feet. This limitation stems from a procedure that telephone companies have used for decades to change the impedance of telephone lines.

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What causes poor network connection? ›

Poor network quality may occur due to the following: Network congestion Routers or other network equipment are overloaded with too much traffic. This could occur on your home network, your Internet service provider (ISP), or your company's local area network (LAN).

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What determines the speed of a digital subscriber line DSL? ›

The speed potential of an ADSL line depends on how far away the subscriber is from the central office. The greater the distance, the lower the data rate. For even the longest runs from 12,000 to 18,000 feet, data rates of up to about 2 Mbps are possible.

How can I improve my DSL line? ›

How to Boost DSL Internet? Improve your Internet Speed

Check for Malware or Viruses. ...
Test your DSL Internet Speed. ...
Reboot your Router. ...
Get a POTS Splitter. ...
Get a DSL Filter. ...
Check Software and Hardware. ...
Minimize Interferences. ...
Get a Wireless Repeater.

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Mar 7, 2022

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What does high bitrate mean? ›

Bitrate is the amount of data encoded for a unit of time, and for streaming is usually referenced in megabits per second (Mbps) for video, and in kilobits per second (kbps) for audio. From a streaming perspective, a higher video bitrate means a higher quality video that requires more bandwidth.

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Should bit rate be high or low? ›

A higher bitrate generally means better audio quality. “Bitrate is going to determine audio fidelity,” says producer and engineer Gus Berry. “You could have the greatest-sounding recording of all time, but if you played it with a low bitrate, it would sound worse on the other end.”

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What bitrate is good enough? ›

Recommended Encoding Settings

Quality	Resolution	Video Bitrate
High	960x540 / 854x480	1200 - 1500 kbps
HD 720	1280x720	1,500 - 4,000 kbps
HD 1080	1920x1080	4,000-8,000 kbps
4K	3840x2160	8,000-14,000 kbps

2 more rows

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What happens when you lower bitrate? ›

Lower bitrate means less data is transferred and, thus, smaller file sizes. It's also possible to encode a video using Constant Bitrate or Variable Bitrate. Constant Bitrate maintains a consistent rate for the duration of the video.

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How does the bit rate work and why is it important? ›

It's typically measured in bits per second (bps) or kilobits per second (kbps). It measures how much data is being transferred from one place to another in a given amount of time. Bitrate is important because it affects the quality of your video and audio streams.

What is the difference between HDSL and VDSL? ›

VDSL is nearly ten times faster than ADSL and is over thirty times faster than HDSL. In the tradeoff for increased speed loop length: VDSL has a shorter reach in the loop.

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What are the primary uses of digital subscriber line and cable modems? ›

Digital subscriber line (DSL) technology is a modem technology using existing twisted-pair telephone lines to carry high-bandwidth applications, such as multimedia and video.

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What data rate is possible both upstream and downstream by HDSL? ›

HDSL: “High bit rate DSL”, is the first DSL technology started in the early 1990s, technically it is a division of the digital trunk into pairs of wires (T1 (US) into 2 pairs and E1 (EU) inti 3 pairs). With HDSL we can reach a bandwidth between 1.5 and 2 Mbps in both senses (downstream and upstream).

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What is the fastest DSL speed? ›

Speeds on your DSL network will vary depending on your provider and plan, as some DSL plans can go as low as . 5 Mbps. But DSL internet service providers (ISPs) offer many plans at 25 Mbps and above. Generally DSL can reach max speeds of around 100 Mbps.

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What is difference between DSL and HDSL? ›

HDSL essentially operates in the same way as ADSL except that it is always symmetrical, which means the data speeds are the same both up and downstream. HDSL can carry both voice and data over a single communication link.

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Is digital subscriber line the only internet connection? ›

Digital Subscriber Line (DSL) is the only Internet connection option available for a small office in the middle of nowhere. Which type will provide speeds above 1.544 megabits per second? Fiber optic cable from a service provider can be delivered directly to the end user.

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What does VDSL mean for internet? ›

VDSL stands for Very High Bitrate Digital Subscriber Line. VDSL is the new generation of broadband internet that uses your copper telephone line but offers faster connection speeds. Like ADSL, the speed of this technology depends on the length of the copper cable from your home to the network equipment.

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What is the most popular form of Digital Subscriber Line? ›

The most common form of DSL technology is ADSL, or Asymmetric digital subscriber line, where the bandwith used in either direction is different.

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What is the data rate of DSL? ›

The bit rate of consumer DSL services typically ranges from 256 kbit/s to over 100 Mbit/s in the direction to the customer (downstream), depending on DSL technology, line conditions, and service-level implementation.

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What type of Internet connection is DSL? ›

DSL is a wireline transmission technology that transmits data faster over traditional copper telephone lines already installed to homes and businesses. DSL-based broadband provides transmission speeds ranging from several hundred Kbps to millions of bits per second (Mbps).

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How is DSL delivered? ›

DSL is high-speed internet delivered via copper phone lines. In the United States, DSL is the primary service available in many rural areas since it can use existing phone lines without needing significant upgrades to infrastructure.

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What happens when landlines go digital? ›

Will any existing devices or services connected to my analogue line continue to work? Changing to a digital phone line means that all of the devices and services connected to your existing phone line will need to be able to work via a router and your service provider may need to provide you with a new one.

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Which speed typically lists DSL speed? ›

The typical speed for a DSL connection is 6 Mbps, compared to the 100 Mbps top speeds offered by many cable companies. The midrange cable Internet plan likely promises 25-50 Mbps.

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Can old phone lines slow down DSL? ›

Old wiring and interference from other devices can slow your DSL connection to a crawl. Spending a bit of time and money to improve your wiring can make a huge difference.

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Does DSL run over telephone line? ›

DSL internet works by running an internet signal over copper phone lines and delivering it to your home, much like older dial-up connections do. But unlike dial-up, DSL offers much faster speeds and won't tie up your phone line. DSL was the first viable broadband internet option available to many people.

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Can I have 2 DSL lines? ›

If you need more bandwidth and faster connection speeds, you can easily bond two separate DSL lines to form a single ultra-fast pipe.

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How do I fix poor network signal? ›

Restart your device.

Restart your device. It might sound simple, but sometimes that's all it takes to fix a bad connection.
If restarting doesn't work, switch between Wi-Fi and mobile data: Open your Settings app and tap Network & internet or Connections. ...
Try the troubleshooting steps below.

How do I fix network connection problems? ›

Try these common fixes first.

Restart your router. This fix works so often that it's always worth trying first. ...
Switch Wi-Fi bands (2.4 GHz and 5 GHz) ...
Test your Wi-Fi on different devices. ...
Try a different Ethernet cable. ...
Improve the position of your device and/or router.

Dec 15, 2022

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What does high-speed DSL mean? ›

The exact definition of DSL is a high-speed internet connection that works through your existing telephone line. It's one of several types of broadband internet connections. Broadband refers to high-speed transmission technologies, including not just DSL but also fiber, cable and others.

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How can I check my DSL speed? ›

Here's how to check your home internet speed:

Connect to your computer to your router using an Ethernet cable.
Open your web browser.
Navigate to www.speedtest.net.
Tap “Go.”

Aug 18, 2018

How do you check your DSL speed? ›

Run a speed test on your computer, phone or tablet

There are plenty of apps and websites that will test the speed of your connection. Some more popular speed test services include Speedtest.net, Fast.com or CloudFlare.

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Will a better router improve DSL speed? ›

Routers can affect internet speed and are responsible for processing and managing every device on your home network. A quality, new router can help maximize your internet speed, while an older one can slow down your connection.

How can I speed up my slow DSL connection? ›

Now let's learn how to increase your internet speed.

Get closer to your router or move the router closer to your computer. ...
Close unnecessary background programs and applications. ...
Clear your browser's cache and your browsing history. ...
Update your computer, especially network drivers & router firmware.

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Jun 3, 2022

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Why does my DSL keep disconnecting? ›

Make sure your modem and router have the latest firmware

Your modem and router need regular firmware updates to function properly with your ISP. If your equipment is running on outdated firmware, your internet may periodically disconnect due to glitches or registration issues.

What is the highest bitrate? ›

There is no best bitrate, only the right bitrate.

Audio CD bitrate is always 1,411 kilobits per second (Kbps). The MP3 format can range from around 96 to 320Kbps, and streaming services like Spotify range from around 96 to 160Kbps.

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What is a good max bit rate? ›

For 1080p videos, the ideal bitrate ranges from 3,500 to 6,000 Kbps. If you're using a standard frame rate (30fps), aim for the lower end of the range, between 3,500 and 5,000 Kbps. If you have a high frame rate (60fps), aim for a bitrate of 4,500 to 6,000 Kbps.

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What is a max bit rate? ›

Recommended maximum bitrate: 4000 Kbps (4 Mbps) Recommended audio bitrate: 96 Kbps or 128 Kbps.

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Which DSL provides the highest data rate? ›

VDSL (very high bit-rate digital subscriber line) is the fastest DSL service. It offers downstream rates of up to 52 Mbps and upstream rates of up to 2.3 Mbps over a single copper wire.

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Is High bitrate good for video? ›

A higher bitrate means better video data, which allows for visual effects artists to more precisely eliminate that colour green and that colour green only. When they do, they can replace it with visual effects that look much more convincing because they're built on a good foundation of digital visual information.

View Details ›

What is an example for bit rate? ›

For example, a network may have a baud rate of 1,200 bauds and a total bit rate of 2,400 bps. When multiple users interact with the network, they share the same 1,200 bauds to transmit data each second and send 2,400 bits each second.

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Is high bitrate good for streaming? ›

A higher bitrate takes up more of your Internet bandwidth. The higher the bitrate, the better the stream quality. So, the higher the bitrate, the faster and more stable your connection needs to be. If you lack a fast internet connection, your stream wanes, leaving your viewers with a pixelated stream.

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Is lower or higher bitrate better? ›

The higher the bitrate, the better the video quality and resolution will be. But it requires more bandwidth and ensures better video quality. In this case, with an optimal bandwidth, streaming with a low bitrate might be a better option.

Read The Full Story ›

How do I lower my bit rate? ›

Reduce the bitrate of the video.

Import and prepare your video in video editing software.
During the Export/Render/Share step, look for a Bitrate setting. ...
Select Variable Bitrate, or VBR, if that option is available.
You may be given the choice between 1 pass encoding or 2 pass encoding when choosing VBR.

Jan 31, 2022

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What is the best DSL type? ›

SHDSL, this type of DSL transmits data at much higher speeds than older types of DSL. It enables faster transmission and connections to the internet over regular copper telephone lines than traditional voice modems can provide.

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What are the 2 types of DSL connection? ›

The most common forms of DSL are asymmetric DSL (ADSL) and symmetric DSL (SDSL).

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How fast is high-speed DSL? ›

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