How to understand the actual wireless transmission speed

When we purchase wireless products, we will refer to the transmission speed in the product parameters, but we do not know that there is something to circle. Let's take a look at the knowledge about the actual wireless transmission speed and theoretical transmission speed. From 2 M of 802.11 to 802.11 M of 108g +, the speed of wireless devices has been greatly improved over the past few years, and it is already similar to the 10/100 Mbps network for ordinary users. However, we all know that either 11 Mbps of 802.11b, 54 Mbps of 802.11g, or 802.11 Mbps of 108g + is a theoretical speed, and the actual wireless transmission speed cannot reach this point, in a normal environment, how fast is the actual speed of a brick wall or a room? That is to say, how fast can the testing speed of wireless networks be achieved without any wireless interference? Next, let's take a look at it.

◆ 802.11b

The maximum theoretical speed of 802.11b is 11 Mbps. The WLAN wireless transmission speed is generally between 3 and 6 Mbps, which is converted to MB1MB = 8 Mb. That is, the transmission speed per second is about 400KB-800KB. Taking the median kb, it takes about two minutes and a half to three minutes to transfer a MB file. This is different from the wired network. due to interference uncertainty in wireless network transmission, the time cannot be accurate ).

It takes at least 25 minutes to transfer a 1 GB file. For games with more than several gigabytes of video files, HD video files, or hard disk WLAN copies with dozens of gigabytes of hard drives, unless you are patient or impatient, so 802.11b, like a 10 m wired network, is not applicable to copying large-capacity Local Area Network files.

◆ 802.11 GB

Because 802.11a is a mainstream non-market consumer, we will not introduce it here. For the actual wireless transmission speed, refer to the 802.11g standard.

The maximum theoretical speed of 802.11g is 54 Mbps. The WLAN wireless transmission speed is generally between 16 and 30 Mbps, which is converted to MB, that is, the transmission speed is about 2 mb-4mb per second. The median value is 3 MB. It takes about 35 seconds to transfer a MB file. It takes at least 4 minutes to transfer a 1 GB file. This speed is sufficient for General Lan applications.

◆802.11 GB +

The theoretical maximum speed of 802.11g + is 108 Mbps. The WLAN wireless transmission speed is generally between 24-50 Mbps and is converted to MB, that is, the transmission speed is about 3 mb-6mb per second. The median value is 4.5 MB. It takes about 25 seconds to transfer a MB file. To transfer a 1 GB file, it takes at least two minutes and a half. The speed is close to Mbps, and more than enough for most WLAN applications.

From the above introduction, we can see that users who usually use wireless LAN do not actually feel such a fast speed. In terms of basic knowledge, "the actual transmission speed of a wireless LAN is less than half of the maximum transmission speed ".

Of course, the above is just the speed we measure in a better state. The real wireless transmission speed is subject to various obstacles such as distance and wall. Other wireless signals, such as mobile phones and microwave ovens, interfere with the speed; encryption and non-encryption have great impacts. When you stay away from the access point, the signal will become weaker and the speed will also decrease. In addition, when others join the network, the bandwidth is shared.

Next let's take a look at the actual wireless transmission speed of the wireless network adapter:

Wireless Network Interfaces can be divided into GPRS and CDMA.

Actual wireless transmission speed of GPRS: basically the same as the Modem speed of 56 kbps.

The actual wireless transmission speed of CDMA is 153.6 Kbps, which is about four times that of home telephone lines.

The wireless network card is also transmitted through wireless transmission, so its speed will also be affected by various obstacles such as walls; other wireless signals such as mobile phones, microwave ovens, and so on.

Summary:

We can see that all the declared wireless devices are the maximum theoretical values, but they still do not meet this standard in actual application. Generally, they have to make a discount, that is to say, the actual wireless transmission speed is only half of the declared speed. In addition, it is still necessary to set the actual wireless transmission speed based on the actual application environment.