What is wlan?

C&T RF Antennas Inc
https://ctrfantennasinc.com/ https://lcantennas.com/ http://www.ctrfantennas.com/
coco@ctrfantennasinc.com
Please Contact us for more information, thank you.
 Coco Lu (+86)13412239096
What Is WLAN?
WLAN definition
WLAN is the abbreviation of Wireless Local Area Network, which refers to the application of
wireless communication technology to interconnect computer equipment to form a network
system that can communicate with each other and realize resource sharing.
A Wireless Local Area Network (WLAN) wireless LAN is a wireless computer network that links
two or more devices using wireless communication to form a local area network within a limited
area such as a home, school, computer laboratory, campus, or office building.
The essential feature of a wireless local area network (WLAN) is that it no longer uses a
communication cable to connect the computer to the network, but connects it wirelessly, which
makes the construction of the network and the movement of the terminal more flexible.
It is a very convenient data transmission system. It uses radiofrequency (RF) technology and uses
electromagnetic waves to replace the old-style twisted-pair copper wire (Coaxial) in the local area
network. It communicates in the air and makes a wireless local area network. It can be easily
used.
WLAN started in 1997. In June of that year, the first wireless LAN standard IEEE802.11 was
formally promulgated and implemented, providing a unified standard for wireless LAN technology,
but the transmission rate at that time was only 1~2 Mbit/s.
Subsequently, the IEEE committee began to formulate new WLAN standards, which were named
IEEE802.11a and IEEE802.11b. The IEEE802. llb standard was first formally promulgated in
September 1999, and its rate is 11 Mbit/s.
The improved IEEE 802.11a standard was officially promulgated at the end of 2001, and its
transmission rate can reach 54 Mbit/s, which is almost 5 times that of the IEEE 802.11b standard.

C&T RF Antennas Inc
 Coco Lu (+86)13412239096
Nevertheless, the application of WLAN has not really started because the entire WLAN
application environment is immature.
After more than two years of development, wireless network products and applications based on
the IEEE802. llb standards have been quite mature, but after all, the access rate of 11 Mbit/s is far
from being able to meet the application requirements of actual networks.
WLAN Pros and cons
WLAN advantage
⑴ Flexibility and mobility.
In a wired network, the placement of network equipment is restricted by the location of the
network, while a wireless local area network can be connected to the network at any location
within the wireless signal coverage area.
Another biggest advantage of wireless local area network is its mobility. Users connected to the
wireless local area network can move and stay connected to the network at the same time.
⑵ Easy to install.
A wireless local area network can eliminate or minimize the workload of network wiring.
Generally, as long as one or more access point devices are installed, a local area network covering
the entire area can be established.
⑶ Easy to carry out network planning and adjustment.
For wired networks, changes in office locations or network topology usually mean rebuilding the
network. Rewiring is an expensive, time-consuming, wasteful and trivial process. Wireless LAN
can avoid or reduce the occurrence of the above situations.
⑷ Easy to locate the fault.
Once a physical failure occurs in a wired network, especially a network interruption caused by a
poor line connection, it is often difficult to find out, and a high price is required to repair the line.
The wireless network is easy to locate the fault, and the network connection can be restored by
replacing the faulty device.
⑸ Easy to expand.
There are a variety of configuration methods for wireless local area networks, which can quickly
expand from a small local area network with only a few users to a large network with thousands
of users and can provide features that cannot be achieved by wired networks such as roaming
between nodes.
Because of the many advantages of wireless local area networks, its development is very rapid.
Now, wireless local area networks have been widely used in enterprises, hospitals, shops,
factories, and schools.
WLAN insufficient
While wireless local area networks can bring convenience and practicality to network users, they
also have some shortcomings. The shortcomings of wireless local area network are reflected in
the following aspects.
⑴ Performance.
Wireless local area networks rely on radio waves for transmission. These waves are transmitted

C&T RF Antennas Inc
 Coco Lu (+86)13412239096
through wireless transmitters, and buildings, vehicles, trees, and other obstacles may hinder the
transmission of electromagnetic waves, which will affect the performance of the network.
⑵ Speed.
The transmission rate of the wireless channel is much lower than that of the wired channel. The
maximum transmission rate of wireless local area network is 1Gbit/s, which is only suitable for
personal terminals and small-scale network applications.
⑶ Security.
In essence, radio waves do not require the establishment of a physical connection channel, and
wireless signals are divergent. In theory, it is easy to monitor any signal within the radio wave
broadcast range, causing communication information to leak.
WLAN topology
The wireless local area network based on the IEEE802.11 standard allows the use of the 2.4GHz
or 5GHz radio frequency band in the ISM frequency band that does not need to be authorized for
wireless connection in the local area network environment. They are widely used, from homes to
businesses to Internet access hotspots.
Simple home wireless WLAN
In the most common and cheapest example of home wireless LAN, a device acts as a firewall,
router, switch, and wireless access point.
Usually, the basic module provides Wi-Fi for 2.4GHz 802.11b/g operation, while the higher-end
module will provide dual-band Wi-Fi or high-speed MIMO performance.
Wireless bridging
When wired to Ethernet or need to establish a second redundant connection for the wired
connection as a backup, wireless bridging allows wireless connections between buildings.
802.11 devices are usually used for this application, as well as wireless fiber optic bridges. Basic
802.11 solutions are generally cheaper and do not require direct visibility between antennas, but
are much slower than fiber optic solutions.
802.11 solutions typically operate in the range of 5 to 30mbps, while fiber optic solutions operate
in the range of 100 to 1000mbps.
Medium WLAN
Medium-sized companies traditionally use a simple design, they simply provide multiple access
points to all facilities that require wireless coverage. This particular method is probably the most
versatile because of its low entry cost, although it becomes difficult to manage once the number
of access points exceeds a certain limit.
Large WLAN
Switching wireless local area networks is the latest development in wireless networking, and
simplified access points are controlled by several centralized wireless controllers.
Another benefit of switching wireless LANs is low-latency roaming. This allows delay-sensitive
applications such as VoIP and Citrix. The switching time will occur within approximately 50
milliseconds, which is usually not obvious.
Requirements for setting up a wireless network

C&T RF Antennas Inc
 Coco Lu (+86)13412239096
Since wireless local area networks need to support high-speed and burst data services, it is also
necessary to solve problems such as multipath fading and crosstalk between subnets for indoor
use. Specifically, the wireless local area network must meet the following technical requirements.
Reliability
The packet loss rate of the wireless LAN system should be lower than 10-5, and the bit error rate
should be lower than 10-8.
Compatibility
For indoor wireless LAN, it should be as compatible as possible with the existing wired LAN in the
network operating system and network software.
Data rate
In order to meet the needs of LAN traffic, the data transmission rate of wireless LAN should be
above 54Mbps.
Communication confidentiality
As data is transmitted in the air through wireless media, wireless local area networks must take
effective measures at different levels to improve communication confidentiality and data
security.
Mobility
Support full mobile network or semi-mobile network.
Energy-saving management
When there is no data transmission and reception, the site machine is put in a dormant state,
and then activated when there is data transmission and reception, so as to achieve the purpose
of saving power consumption.
Miniaturization and low price
This is the key to the popularization of wireless local area networks.
Electromagnetic environment
The wireless local area network should consider the influence of electromagnetic on the human
body and the surrounding environment.
When setting up a wireless local area network, it is often necessary to carefully consider many
detailed factors to successfully build a wireless local area network and ensure its high working
performance.
1. When connecting to a remote LAN through a wireless LAN, the building where the remote LAN
is located should be as visible as possible. If the wireless LAN needs to pass through obstacles
such as tall buildings or dense trees, the transmission performance of the built wireless LAN will
be affected. Impact, after all, those obstacles will directly affect the normal transmission of
wireless LAN data signals.
2. When the distance between the remote network and the local area network is relatively long,
the network transmission bandwidth can be appropriately reduced to achieve the purpose of
long-distance data transmission.
If you really need to carry out long-distance wireless transmission, you might as well try to set up
a wireless LAN relay transfer station in the middle, so that the Internet signal can bypass

C&T RF Antennas Inc
 Coco Lu (+86)13412239096
obstacles.
In a wireless local area network, when network signals are transmitted in short distances, in
order to ensure that the maximum transmission bandwidth can be obtained, several wireless
network bridges must be integrated with each other, and the antenna height of the wireless local
area network is basically not affected.
3. It is also very important to properly set the antenna height of the wireless local area network.
If the antenna height of the wireless local area network device is not set appropriately, simply
relying on methods such as increasing the antenna gain or increasing the power amplification will
result in very limited wireless transmission effects.
Then you can consider arranging the antenna of the wireless node device on the top floor of the
building and try to use a small antenna to ensure the relative concentration of radio waves, which
is beneficial to effectively avoid interference from other wireless LAN signals.
4. Although the frequency hopping technology is used for wireless LAN transmission, the
frequency carrier of the Internet signal is difficult to be detected. Therefore, only when both
parties wirelessly set the same network ID number, can the wireless Internet signal be safely
transmitted.
If you want to further ensure the operational safety of the wireless local area network, you can
also encrypt the wireless Internet signal.
Networking mode
Combining several devices in the WLAN can form a multi-level, wireless, and wired computer
network. Generally speaking, there are two networking modes for wireless local area networks,
one is a WLAN without a fixed base station, and the other is a WLAN with a fixed base station.
A WLAN without a fixed base station is a self-contained network, which is mainly suitable for a
peer-to-peer network formed between computers with wireless network cards.
A WLAN with a fixed base station is similar to the mechanism of mobile communication. The
computer with a wireless network card is connected to the network through a base station
(wireless AP or wireless router).
This kind of network is widely used and is usually used to extend the coverage of a wired LAN or
as broadband access method of wireless Internet.
WLAN without a fixed base station
A WLAN without a fixed base station is also called a wireless peer-to-peer network and is the
simplest type of wireless local area network structure. The WLAN structure without a fixed base
station is a centerless topology.
The communication relationship between the devices connected through the network is equal,
but it is only suitable for a small number of computer wireless connection methods (usually 5
hosts, or within the device).
This networking mode does not require fixed facilities, it can be achieved only by installing a
wireless network card in each computer, so it is very suitable for the formation of some
temporary networks.
WLAN with fixed base station

C&T RF Antennas Inc
 Coco Lu (+86)13412239096
When the number of computer users in the network reaches a certain number, or when a stable
wireless network platform needs to be established, the AP-centric networking mode is generally
adopted.
The AP-centric networking mode is also the most common networking mode for wireless local
area networks. In this mode, an AP is required to act as a central station, and all sites' access to
the network is controlled by the center.
Hardware equipment
1. Wireless network card.
The role of the wireless network card is basically the same as that of the network card in the
Ethernet. As the interface of the wireless local area network, it can realize the connection and
communication between the clients of the wireless local area network.
2. Wireless AP.
AP is the abbreviation of Access Point. Wireless AP is the access point and wireless gateway of
the wireless local area network. Its function is similar to the hub in the wired network.
3. Wireless antenna.
When the network devices in the wireless network are far apart, as the signal weakens, the
transmission rate will drop significantly so that the normal communication of the wireless
network cannot be realized. At this time, the received or transmitted signal must be enhanced
with the help of the wireless antenna.
User Management
The content of the user management of the wireless local area network includes the emphasis on
the management of the files and change records of mobile phone users and the management of
the user data of the exchange in the mobile communication;
User management in broadband ADSL network emphasizes user authentication management and
billing management, and of course also includes user information management;
The distributed system emphasizes the establishment, deletion, permission setting, registration,
connection, and accounting of users.
But all user management is nothing more than the main content that usually includes system IP
address allocation, user database management, user registration, user level management, user
authority settings, user logs, and system working status monitoring.
After introducing a new generation of Internet protocol IPv6, the user management of wireless
local area networks mainly deals with the following aspects.
IP address allocation
The wireless local area network from the user to the wireless access point is a wireless link, so
there is no IP address allocation problem, but once it enters the access network, the AP that
accesses the network will assign a temporary IP to the user.
This IP will be used during the communication between the user and the network until the user
leaves the network, the IP is automatically released.
IP address allocation and management in IPv6 networks mainly include passive allocation and
active acquisition. The active acquisition is calculated through the relevant protocols of the IPv6

C&T RF Antennas Inc
 Coco Lu (+86)13412239096
protocol suite and is mainly obtained through the MAC address of the network card using a
specific algorithm. Passive allocation is obtained by requesting a DHCPv6 server in the network.
Database
The user database is set up to save the user's basic personnel information such as name, gender,
etc., and its purpose is to force the user to register with the real name, and to check whether the
personal information entered during the user registration is correct.
When a user logs on to the website for the first time for user registration, the entire registration
process can only be completed when the entered personal information is consistent with the
content stored in the database, otherwise, the registration cannot be successful.
This part belongs to the content of application layer management and does not require much
change after being combined with IPv6.
Registered
User registration is the basis for the classification and hierarchical management of end users to
ensure the orderly operation of the system. User registration information is the basis for the
system to determine whether a visiting user is a registered user.
To prevent employees with ulterior motives from registering under false names, the client's IP
address and user name, user password, and other personal information can be bundled for
verification.
After being combined with IPv6, the IPv6 protocol itself provides good security, and we can make
full use of some of the advantages of IPv6 to make user registration more complete.
Sign in
When the terminal accesses the network, the network can automatically obtain the IP address of
the visiting client and compare the IP address with the record in the user registration database to
determine whether the visitor is a registered user.
If the client’s IP address-related information is not found in the database, indicating that it is a
terminal that has not been registered, it will be guided to register as a user;
If the IP address registration information exists in the user registry, it indicates that the client has
already been registered, and the user will be prompted to enter his personal information, name,
password, etc., and then compare it with the record in the user registry to verify the user’s
password and confirm the user’s identity.
The confirmed user will be automatically given an identity by the system, and the user’s identity
information whose life cannot be obtained and changed on the terminal can be controlled by the
system.
Level setting
Users usually have a clear and fixed job position in units and organizations, belonging to a certain
department and group, and located at a certain administrative level. Different levels of users are
set by the system administrator based on personnel information and user registration
information.
After this part is combined with IPv6, there is basically no change, that is, there will not be much
change in the access WLAN network in the next-generation all-IP network.

C&T RF Antennas Inc
 Coco Lu (+86)13412239096
Permission settings
In order to prevent users from unauthorized access and arbitrary information publishing activities,
user rights must be restricted. Of course, this has nothing to do with the specific network
protocol, so there is no change in the next-generation IPv6 network.
Log
The user log is the first-hand data to record the click-through rate of the user activity statistical
information column and analyze and improve the network utilization.
The user log is saved in the database, which is convenient for future statistical analysis. The user
log information can be used for statistical analysis such as the information published by the site
and the column browsed by the user during the login time.
This part belongs to the operation of the application layer. After the introduction of IPv6
technology, no changes are required.
The typical application scenarios of WLAN are as follows.
Between buildings
It is simple and cheap to build a network connection between buildings, instead of dedicated
lines.
Catering and retail
The catering service industry can use wireless local area network products, directly from the table
to input and transmit the content of the guests’ order to the kitchen and counter. Retailers can
use wireless local area network products to set up temporary cashier counters when promoting
sales.
Medical treatment
Using portable computers with wireless local area network products to obtain real-time
information, medical staff can avoid delays in treating patients, unnecessary paperwork, delays in
document circulation, and misdiagnosis, and improve the quality of care for patients.
Enterprise
When employees in the enterprise use wireless local area network products, no matter where
they are in any corner of the office, they can send e-mails, share files and browse the Internet at
will.
Warehouse management
General warehouse staff can input the latest data into the computer warehouse system
immediately through the application of a wireless network.
Container terminal
In general, the bridge crane trucks in the container terminal can transmit real-time information
back to the office when the containers are mobilized, so as to facilitate the line-by-line operation
of related operations.
Monitoring system
Generally located in a remote place where the site needs to be monitored, due to the difficulty of
wiring, the remote image can be transmitted back to the main control station through the
wireless network.

C&T RF Antennas Inc
 Coco Lu (+86)13412239096
Exhibition venue
Such as the general electronic exhibition, computer exhibition, because the network demand is
extremely high, and the wiring will make the venue appear messy, so if you can use a wireless
network, it is a better choice.
You may also be interested in the below articles.
2.4GHz/5.8GHz WiFi Antenna Principle And Parameters
5G Millimeter Wave
Secrets of RF Circuit Design
RF Circuit Design Tutorial
Antenna Design Wifi
About Wi-Fi, You Did Not Know

What is wlan?

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to What is wlan?

Similar to What is wlan? (20)

More from Antenna Manufacturer Coco

More from Antenna Manufacturer Coco (20)

Recently uploaded

Recently uploaded (20)

What is wlan?