[Networking Guide] comparison of PLC and ADSL Broadband Access methods

As a broadband network for implementing high-speed Internet, there are currently some practical access methods, such as ADSL, CATV, fiber + LAN Ethernet, and WiMAX wireless access networks, but today we will talk about power line online PLC) and compare it with ADSL to understand it.

PLC is a new "last mile" SOLUTION

Similar to other broadband access methods, PLC is essentially a solution for local telecom or network companies. The "last mile" Wan end access to the user end is called the problem, only through this section is generally within one kilometer, ordinary users can access the wide area network of the telecommunications company, and then access more and more distant Internet.

However, currently, due to technical limitations, it is only possible to connect to low-power grids. Therefore, the commercial PLC solves the "Last one hundred meters" access problem, in the future, when the signal can pass through transformer and other distribution equipment smoothly, the "Last Mile" solution can be implemented completely.

Power Line Communication is a kind of PLC-Power Line Communication Technology. Power Line Communication has a history of decades. It is a technology that can transmit remote data and voice Communication over Power lines. Because the power grid has a huge coverage, people have come up with the idea of using power lines to achieve broadband access.

Power line network applications Power Line Carrier data signal), the low-voltage distribution network as the communication medium to achieve Internet broadband access, home users through the power socket insertion can achieve Internet access.

Network Topology of PLC

Is a typical PLC system application. The PLC main station is installed on the low-voltage outlet end of the distribution transformer. One side of the PLC main station connects the power cable through a capacitor or inductor coupler to inject and extract high-frequency PLC signals.

The other side uses traditional communication methods, such as optical fiber cables, to connect to the Internet. On the user side, the PLC modem directly inserts a wall outlet, extracts high-frequency PLC signals, converts them to Ethernet signals, connects them to the user's computer through the RJ45 port, or adds a small network switch for Small Lan networking.

Comparison between PLC and ADSL

Advantages of power line Internet access:

Power Line Internet access transmits data through power lines. No more lines or other devices need to be added. You only need to insert a modem into a power outlet to connect to the Internet. This is easy to use and low cost. Power lines are spread across cities and villages, and the coverage of existing networks is incomparable. As the power outlets are everywhere, it is very suitable for the construction of LAN, including the internal LAN of the home, the LAN of a unit, and the LAN of a residential area. It is also conducive to the local Internet access of information appliances in the future.

The biggest benefit brought by the PLC broadband network for households is that the network cable is no longer inserted into the home through a wall, which not only saves the household's home from painstaking efforts, but also saves time and effort. Residents no longer need to switch around the fixed network interface in the home, because the PLC mode has already put all the power interfaces in the home to access the Internet. The power line can provide high-speed transmission. The current communication rate varies between MB and MB depending on the specific device ~ Between 45 MB.

Insufficient power line access:

The disadvantages of power line Internet connection are mainly manifested in the noise interference, signal attenuation, low security, and insufficient stability of power lines. Due to these problems, various performance indicators of power line access are relatively low, which are all obstacles to the promotion of power line access. At the same time, the current power line Internet technology is to install the PLC device in the distribution transformer near the user side, the number of users is limited. Therefore, signal transmission via transformer is also an important problem for Power Line Internet access. Only by solving this problem can we make full use of the wide coverage of power lines. In addition, power-line Internet access allows multiple users to share the egress bandwidth, making the user's network speed unstable.

Advantages of ADSL:

ADSL Internet access is the most widely used broadband access method in the world. It has mature technologies, high transmission rates, and stable lines. ADSL uses an existing pair of telephone copper wires to load and reuse devices on the original telephone lines. It makes full use of existing copper wire resources to provide 8 Mbps downstream bandwidth at 640kbps on a pair of twisted wires, generally, household users have exclusive egress bandwidth of 512 KB or 1 Mbit/s, so the user's network speed is relatively stable.

At present, China's telephone network covers most urban and rural areas, and household telephone access has become very popular. As long as the local terminal has a digital user line access multiplexing DSLAM), within the jurisdiction of telephone users can add adsl modem for broadband access. ADSL makes full use of the line resources of the telephone network and reuses the copper line to transmit digital signals. In this way, no special network line is required for accessing the Internet, it is only followed by phone calls, which is easy for users and does not affect the Internet access.

ADSL deficiency:

The ADSL technology has been mature and has been widely used for many years. It is currently a relatively good broadband access method, but the bandwidth provided to users is still small. Due to the bandwidth of the copper wire fully utilized by ADSL technology, there is a high requirement on the line quality. because many of the core diameters of China's copper cables are 0.32mm and 0.4mm, and the quality is not good, it is difficult for some exchange bureaus to activate ADSL on the client. When the line quality is low, it is difficult to have a high bandwidth, and even if you can access the Internet, it is easy to lose the line. Therefore, ADSL can not be installed anywhere. Whether or not ADSL can be installed depends on whether the location is far from the ADSL local device.

Summary:

1. PLC should be better at network coverage than ADSL, but the network company has to pull a large number of optical fiber cables to the residential area until the signal passes through the transformer problem is solved, connect to the network at the low-voltage side of the transformer. However, ADSL uses existing telephone lines to easily achieve the networking of the Last Kilometer. At this stage, the coverage capability is better than that of PLC.

2. PLC because the power cat can access the Internet by inserting a power outlet, it is more convenient to install and networking than ADSL, and PLC does not need to dial, ADSL needs to dial. The installation of ADSL must involve telephone lines, and network wiring must be performed for small local areas in the home.

3. Currently, the PLC can achieve 2 m or a maximum speed of M, but this is the shared bandwidth, and the actual speed of Internet access depends on the number of users. Therefore, at a speed of 2 m, because multiple users share, the actual speed may be lower than that of 1 m single-user single-line ADSL. If a 100 m PLC device is used and the number of users is less, the speed may be slightly higher than that of ADSL.

4. PLC has low requirements on power lines, but ADSL has high requirements on telephone copper lines.

Price comparison between PLC and ADSL

The cost of PLC access is low. The distribution network can be directly used without additional wiring, and the communication speed is faster and faster than that of ADSL. This shows that it is much lower than ADSL in terms of operating costs, and its fast and convenient networking makes it attractive to consumers, but for consumers, the key is how the charges are used.

At present, there is no policy approval for electric power Internet access. Only China Power Grid feihua Corporation runs a large national power line broadband access test network in some communities in Beijing. It is said that there are at least 50 thousand households. Currently, China Telecom uses 12 fixed households or 24 households to share 10 M bandwidth, with a minimum bandwidth of K. Therefore, the fee standard can only be compared with the adsl of the 512K. The price of PLC introduced by China Telecom feihua is as follows:

Billing items		Normal charges	Discount Period Fee
Device Installation		$300	Free of charge
Device Deposit		$400	$200
Internet fee	Yearly subscription	1200 RMB/year	800 yuan/year, 800 yuan at a time, 12 months
	Package for half a year	600 RMB/half year	Pay 480 yuan at a time, use 6 months
	Monthly subscription	Basic monthly fee: 120 RMB	100 RMB/month
	40-hour subscription	The basic fee of 50 yuan is charged for less than 40 hours per month, and the fee of more than 2 yuan/hour	40 hours per month) The basic fee of 35 yuan is charged at a time. The fee is more than 40 hours per month, and the fee is 1.5 yuan per hour.
Note: If the user suspends the PLC broadband service, the company will reclaim the Modem device, and the deposit will be refunded.

The ADSL business standards provided by Beijing Netcom are as follows:

The monthly usage fee is 512 K)

Monthly Usage Fee	Time Limit	Excess
$24.5	20 hours	3 RMB/hour
$49.5	40 hours	3 RMB/hour
$99.5	100 hours	3 RMB/hour
$190	200 hours	3 RMB/hour
$120	Unlimited monthly subscription
Timing	3 RMB per hour (no monthly rent)

The two service pricing standards in Beijing are basically the same. In actual operations, if China Telecom Fei Hua will solicit business fees at a preferential rate of 100 yuan/month, it will be 20 Yuan less than ADSL, and the initial installation fee will be exempted from the monthly rental fee without line, this is obviously attractive to consumers.

Statement:

So far, because power communication has not obtained the permission of basic telecommunications, China Telecom's Apsara stack must also lease the Internet access leased line of China Netcom, which limits the development of power line Internet access. According to the current tariff standards, Power Line Internet access is significantly lower than ADSL.

Once a power line broadband license is applied for, it will pose a threat to telecom operators by virtue of its low access cost, high speed, plug-and-play, and other convenient advantages. China Telecom and China Netcom, which currently have an absolute advantage in the broadband access market, bear the brunt of this problem.

In short, Power Line Internet access is also an expected broadband access method. If it can be improved in terms of network improvement, bandwidth improvement, stable network speed, and preferential charges, because of its wide coverage and ease of networking, users should still be able to pay attention to it.

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