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Computer Network Articles
Page 33 of 122
Complementary Code Keying (CCK)
Complementary Code Keying (CCK) is a modulation technique deployed in wireless local area networks (WLANs) that follow the IEEE 802.11b specification. CCK came into use in 1999 whereby it replaced the Barker code in wireless networks. CCK helps in attaining data rates higher than 2 Mbps, though at the cost of shorter ranges. CCK uses mathematically related code pairs called complementary sequences to encode data more efficiently than its predecessor. This technique enabled the significant speed improvements that made 802.11b networks commercially viable for business applications. How CCK Works CCK operates by using shorter chipping sequences of ...
Read MoreUpgrade your computer for free to windows 10
People who have been using Windows operating systems typically encounter persistent messages to upgrade to Windows 10. The good news is that upgrading to Windows 10 was initially offered as a free upgrade for eligible users. However, this free upgrade period had specific time limitations that users needed to be aware of. Microsoft took a different approach compared to Apple, which allows its users to upgrade to the newest operating system for free at any point. Windows users who missed the free upgrade window would need to purchase a license, which could cost around $119 or more depending on ...
Read MoreHow to build a wireless home network without a router
Setting up a wireless internet connection without a router is usually done using an ad-hoc network. This is a peer-to-peer network configuration where devices connect directly to each other without requiring a central access point. Small businesses and home users often establish ad-hoc computer-to-computer networks when they don't have access to a traditional router. What is an Ad-hoc Network An ad-hoc network allows devices with wireless capabilities to connect directly to each other, creating a temporary network without infrastructure. If you have Windows Vista, Windows 7, Windows XP, or newer systems, you can build your own wireless network ...
Read MoreMultiple Input Multiple Output (MIMO)
In wireless communications, when multiple antennas are used both at the transmitting end as well as the receiving end, the configuration is said to be Multiple Input, Multiple Output (MIMO). MIMO helps in sending and receiving multiple data signals simultaneously over the same radio channel by exploiting spatial diversity and multiplexing. MIMO is a smart antenna technology that significantly improves wireless communication performance. Other related technologies include Multiple Input, Single Output (MISO) and Single Input, Multiple Output (SIMO). MIMO System Configuration Transmitter ...
Read MoreThe 802.11 MAC Sublayer Protocol
IEEE 802.11 standard, popularly known as WiFi, lays down the architecture and specifications of wireless LANs (WLANs). WiFi or WLAN uses high frequency radio waves instead of cables for connecting the devices in LAN. Users connected by WLANs can move around within the area of network coverage. The 802.11 MAC sublayer provides an abstraction of the physical layer to the logical link control sublayer and upper layers of the OSI network. It is responsible for encapsulating frames and describing frame formats, managing channel access, and implementing collision avoidance mechanisms specific to wireless communication. MAC Sublayer Frame Format ...
Read MorePoint Coordination Function (PCF)
Point Coordination Function (PCF) is an optional medium access control (MAC) technique used in IEEE 802.11-based WLAN standards including Wi-Fi. It works alongside the mandatory Distributed Coordination Function (DCF) to provide collision-free access to the wireless medium through centralized polling. PCF operates at the access point (AP) level, where a Point Coordinator (PC) manages channel access by polling stations in a round-robin fashion. This eliminates the contention-based access used in CSMA/CA, providing more predictable and efficient medium utilization. Key Features of PCF Centralized control − The Point Coordinator in the AP manages all medium access ...
Read MoreNetwork Allocation Vector (NAV)
The Network Allocation Vector (NAV) is a virtual carrier sensing mechanism that forms an important part of the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol. It is implemented in wireless network protocols like IEEE 802.11 and IEEE 802.16, operating at the Medium Access Control (MAC) layer to prevent collisions in wireless networks. NAV addresses the hidden terminal problem in wireless networks by providing a virtual mechanism to reserve the wireless medium, ensuring that stations defer transmission even when they cannot physically detect ongoing transmissions. How NAV Works The Network Allocation Vector operates as a countdown ...
Read MoreVirtual channel sensing using CSMA/CA
Virtual channel sensing or virtual carrier sense is a mechanism to predict future traffic in wireless networks that uses Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA). It is implemented in wireless network protocols like IEEE 802.11 and IEEE 802.16, operating at the Medium Access Control (MAC) layer. In virtual channel sensing, a timer mechanism is used based on information about durations of previous frame transmissions to predict future traffic in the channel. It uses the Network Allocation Vector (NAV), which acts as a counter that counts down to zero. How Virtual Channel Sensing Works The virtual ...
Read MoreWhat are beacon frames?
In computer networks, beacon frames are management frames used in IEEE 802.11 based wireless local area networks (WLANs). A beacon frame contains essential network information that a station needs before it can transmit data. These frames serve two primary purposes: announcing the presence of devices in a WLAN and synchronizing devices and services across the network. Beacon frames are integral to the operation of Basic Service Sets (BSS). In infrastructure BSS mode, access points (APs) act as wireless routers forming base stations. All devices communicate through these APs, which transmit beacon frames periodically to inform stations about network status ...
Read MoreAutomatic Power Save Delivery (APSD)
In IEEE 802.11 wireless LANs, Automatic Power Save Delivery (APSD) is a mechanism that aims to reduce power consumption by the devices connected in the network. It was originally introduced to IEEE 802.11e in 2005 to address the growing need for energy-efficient wireless communications. How APSD Works APSD is generally deployed in infrastructure BSS (basic service set). In infrastructure BSS, there are access points (APs) which are basically wireless routers forming the base stations for access. All the wireless devices (clients) communicate with each other through the APs. When a client has frames to send, it sends the ...
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