Wireless Standards and Technologies

Frequencies and Range Wireless networks work with certain frequencies, which are primarily 2.4 and 5 GHz. Here is the breakdown of the wireless networks that use each one of them: - 5 GHz(_____,_____,_______,_____) -2.4 GHz(____,____,____,____)

- 5 GHz 802.11a 802.11n 802.11ac 802.11ax - 2.4 GHz 802.11b 802.11g 802.11n 802.11ax NOTE: The 802.11n and 802.11ax wireless networks can work with both 2.4 and 5 GHz frequencies. The range of each of the networks is as follows: 802.11a - 50 feet 802.11b - 150 feet 802.11g - 50 feet 802.11n - 175 feet 802.11ac - 230 feet 802.11ax - 11 feet

Antenna Types Wireless antennas are there in devices with wireless network capabilities. There are essentially two types of wireless antennas: 1)______________, throws the signals in a specific direction. 2)_______________, throws the signals at 360-degree.

1: Directional or Unidirectional 2: Omnidirectional You can use directional or unidirectional antennas to extend the wireless signals into a specific dead zone. For example, if you have a dead zone, you can use a unidirectional or directional antenna to extend the signals into that specific zone. Omnidirectional antennas are used for point-to-point connections.

This runs at 54 Mbps and is not compatible with 802.11b as it operates at the 5 GHz band. This standard was the first amendment of the original legacy IEEE 802.11 standard (1997), improving data rates from up to 2 Mbps of the original standard. It can cover an indoor area ranging from 35m to 125m.

802.11a

also known as WiFi 5, offers a speed of 1.33 Gigabits and a similar range to 802.11n (230 feet). Characteristics of this standard include the introduction of wider channels (80 or 160 MHz compared to 40 MHz for 802.11n) in the 5 GHz band, more spatial streams (up to 8), and the addition of Multi-User MIMO (MU-MIMO). Can transmit data at 1300 Mbps (megabits per second) or 162.5 MBps (megabytes per second).

802.11ac, Despite the speed and range of different wireless standards, they need to be used correctly. For example, if the wireless router or access points are not hardened, then no standard is safe for use.

also known as WiFi 6, is an improvement of its predecessor, which was 802.11ac. Can operate in 2.4Ghz and 5Ghz frequency ranges. It can support up to eight MU-MIMO transmissions. It can provide four times the speed of 802.11ac.

802.11ax

This provides a range of 150 feet and is the oldest standard still in use and supported by wireless routers. Wireless devices widely support this. Provides data rates of up to 11 Mbps using the 2.4 GHz band. This standard provides lower maximum data rates but a greater range than the 802.11a standard since the 2.4 GHz frequencies used are not as readily absorbed by walls and obstacles as the 5 GHz frequencies used in 802.11a are.

802.11b

Today, this is supported by wireless devices and network equipment and is an economical option for buying a wireless access point. Is the same speed as 802.11a. However, it has a longer range of 170 feet and supports the 2.4 GHz, frequency band. Provides data rates of up to 54 Mbps. This functions in the 2.4 GHz band (like 802.11b) but uses the same Orthogonal Frequency-Division Multiplexing (OFDM)-based transmission scheme as 802.11a. A wireless keyboard also operates at the 2.4 GHz band, hence can likely cause interference with the 802.11g network.

802.11g

This is faster than 802.11g, also known as WiFi 4, and is supported by network devices. Has a network speed of 600 Mbps and a maximum range of 230 feet. This standard uses multiple input/multiple outputs (MIMO) and may cause interference with nearby 802.11b/g networks. Has a higher price point than 802.11g.

802.11n

an operating mode in which you have one access point and several wireless clients. When the wireless clients need to connect to the wired network, they must first authenticate themselves with the access point. After the wireless clients are authenticated, they can communicate with the clients on the wired network. Since there is only one access point, the mobility of the wireless clients is not supported. With the use of an access point, this mode is also known as the infrastructure mode. It can work only in a limited area depending upon the signal spread of the access point.

Basic Service Set (BSS)

Each channel in wireless has a certain throughput. To increase the throughput, you can configure channel bonding, which requires you to combine two adjacent channels into one channel. The new combined channel has the throughput of both the channels, but you can only create channel bonding if both the channels are adjacent to each other. For example, if you are using 802.11n, which uses 20 MHz channels, you can combine two channels and create a channel bonding of 40 MHz.

Channel Bonding

works similarly but with a slight difference. Instead of one access point, it has a physical subnet that has more than one access point. After a wireless client authenticates with one access point, it can roam around and connect with different access points. The access points are configured so that they can share information of the authenticated wireless clients. There can be several access points. Each one of them needs to have the same SSID. The name of the access point, known as BSSID, can be different, however. For example, let's assume that there are four access points with the same SSID. Each can have a unique BSSID, such as BSSID1, BSSID2, BSSID3, and BSSID4. With several access points, a larger surface area can be covered, and many users can be supported.

Extended Service Set (ESS)

If you have ever connected your mobile phone with another one using Bluetooth, you have created an ad-hoc wireless network. It is also called the Independent Basic Service Set (IBSS) that requires no access point or router in between. In an ad-hoc or IBSS, both devices communicate with each other without any controller in between. A wireless router or access point is required to authenticate the wireless clients.

Independent Basic Service Set (IBSS), Other than IBSS or ad-hoc network, it is also known as a peer-to-peer network. With the invention of high-speed wireless networks, this type of network is now rarely used. However, it can still be used in situations where you need to transfer files from a mobile device to another mobile device or a tablet.

The 802.11n and 802.11ac wireless standards have a feature named Multiple input multiple output or MIMO. When a signal is being sent out, it is broken into several streams, which are delivered using different antennas on the wireless router or the access point. The recipient, on the other side, recombines the streams into the original signal. This method is called spatial multiplexing. However, to use this feature, both the sender and recipient devices need to have this capability. A Single User MIMO or SU-MIMO is capable of serving one device at a time. Multi-User MIMO or MU-MIMO works similarly with one significant difference - it can simultaneously serve more than one device. MU-MIMO was introduced in 802.11ac standard but was able to cater only to the downlink connections. With the recent launch of 802.11ax, also known as WiFi 6, it can now support uplink connections. An important fact to note is that it works only with the 5GHz frequency band.

Multiple Input Multiple Output (MIMO) and Multi-User MIMO (MU-MIMO)

It is possible to configure roaming for wireless clients. When we use the term, the wireless clients can move from one access point to another while keeping a persistent connection. The access points need to be configured with the same SSID.

Roaming, In the roaming process, there is a handoff process that needs to be completed. The handoff process includes three key steps: 1. Scanning: A wireless client finds another access point when the connection is lost or has moved away from one access point. 2. Authentication: The client device sends an authentication request to the access point. The access point verifies the client's device and authenticates accordingly. 3. Association: The client device sends the association request to the newly found access point. After the association process is completed, the new access point sends a message with the disassociation packet to the old access point. After the old access point dissociates from the client, the new access point updates the routing tables. You need to set up two or more access points with the same SSID for the roaming process.