Moumita has Published 175 Answers

What are the IEEE 802.11 Wireless LAN Standards?

Moumita

Moumita

Updated on 09-Jan-2020 07:45:29

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 for connecting the nodes.There are several standards of IEEE 802.11 WLANs. The prominent among them are 802.11, 802.11a, 802.11b, 802.11g, 802.11n and 802.11p. All the ... Read More

The 802.11 Frame Structure

Moumita

Moumita

Updated on 09-Jan-2020 07:41:13

The IEEE 802.11 standard, lays down the architecture and specifications of wireless local area networks (WLANs). WLAN or WiFi 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 ... Read More

Using Aggregate function to fetch values from different tables in SAP

Moumita

Moumita

Updated on 05-Dec-2019 08:04:28

First of all, the example you gave has different description for a fund. So, you should know which one to be kept. If you want to keep any description, you can use the below query using aggregation functionsSELECT    X1."FundName"    , min( X0."Dscription")    , X0."FundId" FROM INV1 X0 ... Read More

Inter – frame spaces (RIFS, SIFS, PIFS, DIFS, AIFS, EIFS)

Moumita

Moumita

Updated on 02-Dec-2019 10:19:09

Inter – frame SpacesInter − frame spaces (IFS) are waiting periods between transmission of frames operating in the medium access control (MAC) sublayer where carrier-sense multiple access with collision avoidance (CSMA/CA) is used. These are techniques used to prevent collisions as defined in IEEE 802.11-based WLAN standard (Wi-Fi).IFS is the ... Read More

Transmission opportunity (TXOP)

Moumita

Moumita

Updated on 02-Dec-2019 10:15:42

Transmit opportunity (TXOP) is a MAC layer feature used in IEEE 802.11-based wireless local area network (WLAN). TXOP defines the time duration for which a station can send frames after it has gained contention for the transmission medium. By providing this contention-free time period, TXOP aims to increase the throughput ... Read More

Extended Inter-Frame Spacing (EIFS)

Moumita

Moumita

Updated on 02-Dec-2019 10:13:52

Extended inter-frame spacing (EIFS), is a waiting period used in MAC layer of IEEE 802.11-based wireless local area network standard (WLAN standard). It is an additional waiting period used in addition to the mandatory DISF technique in case of corrupted frames.DISF (Distributed coordination function inter-frame spacing) is inserted before sending ... Read More

Rate Anomaly in CSMA/CA

Moumita

Moumita

Updated on 02-Dec-2019 10:07:18

Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) is a network protocol for carrier transmission that operates in the Medium Access Control (MAC) layer. CSMA/CA prevents collisions prior to their occurrence and is ideally used in wireless communications.Rate anomaly occurs when the performance of a high speed station is impaired ... Read More

Arbitration Inter-Frame Spacing (AIFS)

Moumita

Moumita

Updated on 02-Dec-2019 10:05:44

Arbitration inter-frame spacing (AIFS), is an optional technique used to prevent collisions in IEEE 802.11e based WLAN standard (Wi-Fi), in the medium access control (MAC) layer. It determines the time interval that a station should wait before it sends its request frame, by prioritizing the stations based upon the Access ... Read More

Short InterFrame Spacing (DIFS)

Moumita

Moumita

Updated on 19-Nov-2019 11:02:21

Short Interframe Spacing (SIFS), is the time interval required by a wireless device in between receiving a frame and responding to the frame. It is used in Distributed coordination function (DCF) scheme, which is a mandatory technique used to prevent collisions in IEEE 802.11-based WLAN standard (Wi-Fi).The duration of SIFS ... Read More

DCF InterFrame Spacing (DIFS)

Moumita

Moumita

Updated on 19-Nov-2019 11:00:15

Distributed coordination function (DCF) is a mandatory technique used to prevent collisions in IEEE 802.11-based WLAN standard (Wi-Fi). It is a medium access control (MAC) sublayer technique used in areas where carrier-sense multiple access with collision avoidance (CSMA/CA) is used.Using DCF technique, a station needs to sense the status of ... Read More

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