0, making short guard interval mandatory is emphasized as this was a change from 11ac PHY, which caused the confusion. MU-MIMO is an enhanced form of the MIMO. A preamble of the data unit is. Short Guard Interval. 802. 11n, shorter guard intervals are possible. MU-MIMO is short for Multi-User, Multiple-Input, Multiple-Output. Short Guard interval & Aggregation. 2 µs) GI. MCS: SU MCS/MU. n 802. GI (Guard Interval) is intended to solve the problem based on delays, and Short GI is used to improve the throughput of the wireless network based on the GI in the environment with small delays. You’d be missing a valuable opportunity to improve your network’s performance right from the get-go. Notice the RSSI is -44 and we are just using 64 QAM, you really have to be close and have a clear spectrum to achieve 256 QAM. If you would use mixed mode, always make sure these are disabled, as these features were designed to be used with 802. 4) Alternatively, if your setup has all latest. 11n you can choose between a short guard interval and a long guard interval. Received signal for CP-OFDM, ZP-OFDM and KSP-OFDM. 4/0. . Systems, methods and other embodiments related to single stream wireless communication with a green field preamble using a short guard interval are described. If you would use mixed mode, always make sure these are disabled, as these features were designed to be used with 802. ap (config-if)#end. long Enable 802. With this link speed assuming minimum airtime utilization, client could achieve 750 to 800 MBPS of internet bandwidth. If this field. Hence, in TGaf capable devices shall support both guard interval modes (short and normal). MU-MIMO is an enhanced form of the MIMO. 802. An AP identifies any signal content. 11ac is not directly defined in data rates speed, but is rather a combination of 10 modulation encoding scheme (MCS 0 to MCS 9), a channel width ranging from 20mhz (1 channel) to 160Mhz (8 channels), a number of spatial streams (typically 1 to 4). For normal guard intervals (800 ns): 0 to 32 samples. It is referred as HT (High Throughput) specification. Top. Reply Reply Privately. Other: User entered Guard Interval values between 0 to 1. 8 µs), double (1. The guard interval is at a very basic. 8 μs. This is kind of half right. Fig. Congestion Issue WiFi has no congestion detection, and its mechanism is designed for avoiding collisions. If you would use mixed mode, always make sure these are disabled, as these features were designed to be used with 802. Just starting to mess around with Home Networking. Short Guard Interval. What is the 11n guard interval? Intersymbol interference, also known as ISI, is eliminated by the guard interval. 11n on 5GHz. This interval helps data reception avoid delays due to Inter-Symbol Interference (ISI) and overcome echoes (reflection of sound waves). The guard interval prevents Inter-Symbol and Inter-Carrier Interference (ISI, ICI). These high throughput wireless standards have a large pool of link configuration parameters at the both physical (PHY) and media access control (MAC) layers, which include channel bonding, multiple input multiple output (MIMO) technology, short guard interval, advanced modulation and coding schemes (MCS), frame aggregation,. Data frames will be divided into several symbols when being transmitted. For short guard intervals (400 ns): 0 to 16 samples. You can see the gains that a short guard interval provides in the 802. 220 Mbps – Guard Interval ustawionym na 800ns. Enable or disable use of short (400 ns) guard interval in 20 MHz Megahertz mode. If the short guard interval does not allow enough time for reflections to settle in your mesh deployment, inter-symbol interference values may increase and degrade. . Short GI NSYM Disambiguation — A bit that indicates if an extra symbol is required when the short GI is used. Tail bits: must all be 0. Channels. Let’s take an example connection between an AP and client both capable of 4 spatial streams, 40 MHz channels, 256-QAM 5/6 coding rate, and a Short Guard Interval. Caranya sangat mudah, cukup dengan membuka browser yang biasa kamu gunakan lalu memasukkan IP Adress modem. Otherwise only Downlink performance (AP to STA) will improve. There are a lot of. 11n only, you may. Your ubiquity probably does 2 streams, be happy with 130mbit. Short Guard interval (400ns) - optional (though optional but is widely supported) LDPC (Low density parity check code) - optional STBC (Space time block. 11 OFDM-based communications, Guard Interval is used to ensure that distinct. 4 GHz Spectrum Capabilities 20 MHz Channel Width in 2. The regular guard interval is 800ns. DURHAM, N. Этот интервал помогает при. 2. 4GHz frequency band unlike 11n. Click this checkbox to enable or disable a short preamble for 802. 11 operation is 800 ns. Short guard interval in 20 MHz Megahertz mode. 2. Enable Short Guard Interval : Enabling Short Guard specifies an interval of 400 Nano seconds (ns) as opposed to the standard of 800 ns. 11ax introduces new guard interval options. 11a/g 所做的改进。 射频芯片在使用 OFDM 调制方式发送数据时，整个帧是被划分成不同的数据块进行发送的，为了数据传输的可靠性，数据块之间会有 GI ，用以保证接收侧能够正确的解析出各个数据块。 A shorter guard interval results in a shorter symbol time, which increases the data rates by about 10% and increase throughput greatly. g. Enabling a short guard interval can decrease network overhead by reducing unnecessary idle time on each access point. If necessary, the WLC configuration can be changed to only use the slower long guard interval. Systems, methods, and other embodiments associated with a single stream wireless communication with a greenfield preamble that uses a short guard interval are described. 4 GHz 2x2 MIMO. Set the duration of the transition time (Ttr) in the windowing function. r/wifi. TX Power Control. Use the VLAN pool when available. • Primarily used on AP side to reduce Guard interval between frames to improve performance. TX Power Control. TX PowerWLAN知识点——GI（Guard Interval）. If this option is available, select an option from the drop-down list, otherwise skip to the next step. This is kind of half right. Enable or disable use of short (400 ns) guard interval in 20 MHz Megahertz mode. Systems, methods, and other embodiments associated with a single stream wireless communication with a greenfield preamble that uses a short guard interval are described. Yes — Reduces transmission time to every 400 nanoseconds when communicating with clients that also support the short guard interval. We can see that the host has 2 Spatial streams, is using a Short guard interval , 40 MHz channel and the data rate is 300 – the data rate is the highest capable with these settings. Short GI: disabled – Short Guard Interval decreases the time between data characters being sent wirelessly. Most reflections are received quickly. Enabling a short guard interval can decrease network overhead by reducing unnecessary idle time on each access point. However for office environments, having a Short Guard Interval (SGI), which lowers the interval to 400ns, can give you an increased data rate of 11%. Enable or disable use of short (400ns) guard interval in 20 MHz mode. Short Guard Interval (What is Guard Interval?) Guard Interval is used to avoid signal loss from multipath effect. Channels. 11 OFDM is 800 nanoseconds in duration. Short guard interval in 20 MHz mode. 11n 针对 802. Short Guard Interval (SGI) is a protocol that lowers the guard interval by 400ns and improves the wireless data rate. Guard intervals (GI) are necessary in OFDM to reduce the likelihood of interference between two consecutive _____. client-monitor policy default_Policy problem-type networking trigger-times 3 report-interval 3600. The guard interval is the period in nanoseconds the radio listens between packets. To increase data rate, 802. The Other selection inputs a non-standard Guard Interval value between 0 and 1. Shows high-throughput rate information for a Basic Service Set (BSS). 8 µs Since the subcarrier spacing is reduced by a factor of four, the OFDM symbol duration is increased by a factor of. With the internet connection you have you can max it out by using single stream with a 40MHz wide channel short guard interval enabled since that goes up to 150Mbps. By default, all avail- able channels are enabled. برای حالت اول باید حتماً تیک زده شود و یا فعال شود ( با فعال کردن این گزینه پهنای. The. All other default profiles have ap-country NL. This gives a safe time between transmissions. Description. 11a/b/g used a mandatory 800ns guard interval. Penambahan guard interval wifi dapat menambah konsumsi daya baterai pada perangkat wifi, karena durasi antara sinyal yang dikirim dan diterima. • Helps improve data rate in Up/Down if both AP and STA support Short GI. Systems, methods, and other embodiments associated with single stream wireless communication with greenfield preambles using short guard intervals are described. A short guard interval of 400 nanoseconds (ns) will work in most office environments as distances between points of reflection, as well as between clients, are short. MinstrelHt is 110In various embodiments, this disclosure describes symbol blocking structures and guard intervals (GIs) for example use in connection with single carrier (SC) multiple input multiple output (MIMO) single channel and channel bonding transmission. The first 8 modes correspond to short guard interval disabled and channel bonding disabled. I accessed my fiber modem (It has RouterOS 7. ap. Reveal Solution Discussion 1. Short GI(Guard Interval) 是 802. 2. In an optimal radio environment that could increase throughput but in less than optimal conditions it will instead lead to errors, retransmissions, instability and decreased performance. When turned OFF, the Guard Interval is 800ns. Learn about the benefits of our new ePMP release 4. Short GI(Guard Interval) 是 802. 67 (MCS Index 9) / 3. Any idea how I get the AP to use the NL country code?The guard interval acts as a buffer zone that helps separate the symbols and mitigate ISI. normally you can configure that the access point will use. A guard interval is a period of time between transmissions that allows reflections from the previous data transmission to settle before an AP transmits data again. 7. Short Guard Interval Supported — This field is available only if the selected radio mode includes 802. Short Guard. 3. What would be the downside of having a short GI? 9. 4 GHz (Radio 1) 5GHz:For this IIR channel, a joint design for precoding, power gain control and equalization of cooperative OFDM relay systems is presented. Select to enable the short guard interval. 4. A discussion thread on whether to enable or disable Short Guard Interval (SGI) feature in ddwrt firmware when using Mixed N/G mode for wireless routers. 11n-2. The regular guard interval is 800ns. r/HomeNetworking. 11n only, you may wish to. C. For example, in DVB-T, guard intervals are available as 1/32, 1/16, 1/8 or 1/4 of a symbol period. 室内环境干扰因素小. 5 Mbit/s per MHz and spatial stream, or slightly more than half the advertised bitrate. 例えば電気信号を無線通信など空間を伝搬さ. ao link. The guard interval can be shortened to increase throughput by up to 10 percent. Interval. For HIPERLAN/2, both 1/4 and 1/8 are selections. A guard interval is a period of time between transmissions that allows reflections from the previous data transmission to settle before an AP transmits data again. In an optimal radio environment that could increase throughput but in less than optimal conditions it will instead lead to errors, retransmissions, instability and decreased performance. Picked this up for $60. The short guard interval is enabled for the highest enabled MCS data rate. since 802. Short GI: disabled- Short Guard Interval decreases the time between data characters being sent wirelessly. Single radio/antenna devices do not support mimo and still having trouble with inter symbol interference by multipath, especially in warehouses where barcodescanners are used. 800 ns short guard interval. 2 microseconds of. radio profile radio_ng_ng0 benchmark phymode 11b rate 11 success 60 usage 50. 4). This provides an 11% increase in data rate. 11n data rate. 11ad router in January 2016. Một kỹ thuật được gọi là Short Guard Interval cũng góp phần cải thiện khoảng 10% vận tốc bằng cách giảm khoảng cách giữa các symbol (ký hiệu) từ 4 nano giây xuống còn 3,6 nano giây. cc. Menambah Konsumsi Daya Baterai. For indoor with lot of multi path,its best practice to use long guard interval, as there will be higher possibility of interference from reflections with having it as short. Guard Interval: 800ns: Security Settings: WPA2-PSK/WPA2-Enterprise: WPA Encryption: AES: WIFI 5G. 11ac, the Long Guard Interval (LGI) factor is 4 and Short Guard Interval (SGI) is 3. Short Guard Interval (SGI), 20 and 40 MHz • Primarily used on AP side to reduce Guard interval between frames to improve performance • Helps improve data rate in Up/Down. 900 Mbps (two spatial streams at 80 MHz, short. • Helps improve data rate in Up/Down if both AP and STA support Short GI. • Guard Interval: Choose either Long (800 ns) or Short (400 ns) that the security appliance will retry a frame transmission that fails. 160 MHz channel, 1 spatial stream, short guard interval, VHT, MCS7 (up to 650 Mbps). 38 inches (86 x 86 x 35 mm) Weight 1. 11n specs. 11n added optional support for a 0. On Advanced tab: set Preamble Length to Short. 112 Mbps – Guard Interval ustawionym na 400ns. Short guard interval in 20 MHz mode. 802. The. 11n added optional support for a shorter 0. TX Power (%) If Auto TX Power Control is disabled, enter the TX power in the form of the percentage of the total available power. Systems, methods, and other embodiments associated with a single stream wireless communication with a greenfield preamble that uses a short guard interval are described. Enable or disable use of short (400ns) guard interval in 20 MHz mode. 11n. For each VAP you add you need to increase Beacon Interval by 100. Short Guard Interval RF Architecture Bands Supported Transmit (Tx) Receive (Rx) 2. GI (Guard Interval) is intended to solve the problem based on delays, and Short GI is used to improve the throughput of the wireless network based on the GI in the environment with small delays. Symbol duration 3. are made simultaneously or within a short interval, listing particulars shall be drawn up in accordance with the rules laid down in this Directive in the Member State in which the issuer has its registered office. A guard interval is a period of time between transmissions that allows reflections from the previous data transmission to settle before an AP transmits data again. 3 lb (0. Split usage of 2. This field is available only if the selected wireless radio mode includes 802. Pastikan bahwa perangkat yang kamu gunakan untuk masuk ke halaman konfigurasi modem telah terhubung dengan WiFi. 8 µs 0. These longer guard intervals help to prevent inter-symbol interference in outdoor environments and therefore improve coverage and performance. I recently got a Unifi system, thinking they would be customization since it's enterprise, but there is no way to adjust advanced wireless settings such as "Frame aggregation", "Preamble Length", and "Short Guard Interval". The SGI (Short Guard Interval) defines the time interval between transmitted symbols (the smallest unit of data transmitted at one time). When the classic (long) guard interval of 800ns is used, only 3. 11 set of protocols (which is part of the Wi-Fi networking family), providing high-throughput wireless local area networks (WLANs) on the 5 GHz band. Just out of curiosity, what is your go-to configuration when setting up FortiAP profiles? Do you usually enable WIDS? What about frequency and AP handoff? Short guard interval? Power control? Monitor channel utilization? I know what these things all do, but I'm not sure how these features play together or if the "default" is a good starting point. 4 µs or 0. Short Guard-interval : Select to enable the short guard interval. thecompnerd. How to Use Command Lines. Orthogonal frequency division multiplexing (OFDM) symbols of the data portion are generated using one of (i) a normal guard interval, (ii) a short guard interval and (iii) a long guard interval. Set with class: BooleanValue Underlying type: bool802. Short Guard Interval (400ns), który to parametr tylko w teorii pozwala nam na osiągniecie. undo short-gi. guard-interval (any | long; Default: any) Whether to allow use of short guard interval (refer to 802. IEEE802. However, enabling this parameter can also have a negative impact. Support of the 400ns GI is optional for transmitting and receive. 104 ms Answer (s): AReference: QUESTION: 29 What statement about the beamwidth of an RF antenna is true?The heartbeat interval range is 1 to 20 (100*ms). Scrambler Initialization Range: 0 to 127 Default: 93 Guard Interval (GI) คือ ช่องว่างระหว่าง Channel เว้นไว้เพื่อไม่ให้คลื่นซ้อนทับการ โดยความเข้าใจปกติเราจะคิดว่าคลื่นถ้าส่งด้วยความถี่. Table 8. Be sure the wireless client can support this to avoid compatibility issues. The available channels depend on which IEEE wireless protocol you selected in Band. 11 {a | b} 11nsupport rifs rx {enable | disable} Save your changes by entering this command: save config Short guard interval (SGI) is a new feature of the physical (PHY) layer in High Throughput Wireless Local Area Networks (HT-WLANs), like IEEE 802. — University of Southern Indiana men’s basketball coach Stan Gouard and Duke coach Jon Scheyer. Actual exam question from CWNP's CWNA-107. Packets larger than the size you specify here will be fragmented. By default, all available channels are enabled. 11n and 802. 例えば電気信号を無線通信など空間を伝搬さ. cfgHT = wlanHTConfig(Name,Value) sets properties using one or more name-value pairs. 10 msC. 11ax is the smaller subcarrier spacing (78. 802. With the advantage of tolerating shorter guard interval and noise in the temporal burst processing window, the burst equalization (Burst ANN) enables a short guard interval length that occupies 1/5 of the useful duration in this system. Stick to 1, 6, and 11 (in the USA). Like My Facebook Page ? i have a 10$ Course on Udemy!Short Guard Interval Cyclic-Delay Diversity Space Time Block Code All thees options are OFF right now, i haven't touched them because idk what they do, that's why i'm here. As mentioned 11ac products are available in 5GHz frequency band only and not available for 2. 11n makes the short guard interval an option in 2. 4 μs guard interval. However, for office environments, having a Short Guard Interval (SGI), which lowers the interval to 400ns, can give you an increased data rate of 11%. All clients and access points on overlapping channels talk to each other. 1. See also 802. 11n, interval penjaga telah dikurangi dari 800 ns menjadi 400 ns untuk meningkatkan throughput. Use either the short guard interval (Short GI) of 400 ns or the long guard interval (Long GI) of 800 ns. A method for receiving a beacon frame comprises the steps of: receiving a first beacon frame which contains guard interval type information; determining a second beacon frame which is to be received after the first beacon frame on the basis of the. It is not to be confused with the space between packets, which is the inter-frame space (IFS). Você vai mexer com ajustes wifi de sincronização, de transmissão de pacotes, semáforos, e outras configurações de ajustes avançados do sinal Wi-fi. 11n mode allows for a reduction in this guard interval from the a and g definition of 800 nanoseconds to 400 nanoseconds. There may be a way via the command line, and if anyone knows, please tell. 2. Otherwise only Downlink performance (AP to STA) will improve. 4. Choices: disable; power-save;Use short-gi enable to enable short Guard Interval (GI). Some have mentioned low power small cells. B QUESTION: 28 You are reconfiguring an AP to use the short guard interval. The standard symbol guard interval used in 802. By analyzing the noise sources, this. You, as the designer of an OFDM system, define the length of the CP based on your requirements. 802. A short guard interval of 400 nanoseconds (ns) works in most office environments as distances between points of reflection, as well as between clients, are short. When you add a guard time, the back portion of useful signal time is copied and appended to the front. A guard interval is a period of time between transmissions that allows reflections from the previous data transmission to settle before an AP transmits data again. 11a. The guard interval can be shortened to increase throughput by up to 10 percent. Join. A heartbeat interval of 2 means the time between heartbeat packets is 200 ms. 11n/ac/ax/be Demod Properties > Format tab The Guard Interval is the ratio of the Cyclic Prefix "CP" time to the inverse FFTtime "T (IFFT). 11n bands. 2 ∕ 4 = 250kbps. Cisco supports SGI on a 20MHz channel in the 2. 6/3. • 11 days ago. Configure Multi-SSID 5. • Part of Mixed mode frame format. Longer guard intervals provide improved performance in environments with multi-path and delay spread. Select Channel Width. The SGI allows for more user data by reducing the long GI data area, but SGI is more susceptible to errors caused by delay spread and. Many translated example sentences containing "short guard interval" – Italian-English dictionary and search engine for Italian. disable. 4 GHz mode using short GI. 400 Mbps (two spatial streams at 40 MHz short guard interval) This is a full third faster than the comparable 802. 1 Channelization When the OFDM PHY was introduced to 802. 2 microseconds of data. In this video, i tell about to improve home router network stability. 02 lb (0. Printer-friendly specifications. 2 MinstrelHtWifiManager MinstrelHt (Figure 2), extending the legacy Minstrel model, is based on the Linux implementations of the same name. Một kỹ thuật được gọi là Short Guard Interval cũng có thể góp phần cải thiện khoảng 10% tốc độ. Ajuste o Beacon Interval: O Beacon Interval (Farol) é um quadro (frame) de sincronização enviado em períodos constantes pelo roteador wifi. A sua principal função é a de avisar. When short guard interval is used (400ns GI), a subcarrier carries 312. Some outdoor deployments, may, however require a longer guard interval. IGMP snooping allows. Usage guidelines. • Primarily used on AP side to reduce Guard interval between frames to improve performance. 11b preamble short (Cisco Controller) > (reset system with save). A method for receiving a beacon frame comprises the steps of: receiving a first beacon frame which contains guard interval type information; determining a second beacon frame which is to be received after the first beacon frame on the basis of the guard interval type information; and receiving the second beacon frame, wherein the guard interval type. This would avoid any kind of data loss from wireless interference; Reduce beacon interval to 100 or 200 from default 400. Under Authentication Type choose WPA2-PSK, Cipher type AES. Most reflections are received quickly. The Enable Short Guard Interval and Enable aggregation options can slightly improve throughput. Cyclic-Delay Diversity Cyclic Delay Diversity (CDD) is a diversity scheme used in OFDM-based telecommunication systems, transforming spatial diversity into frequency diversity. Using personal security mode for your. In most cases a 400 nanosecond guard interval is sufficient and is referred to. Short Guard Interval In normal 802. The purpose of a guard interval is to. C. Setelah itu, ada beberapa pilihan dari menu network yang sudah terbuka. Select to enable the short guard interval. Short GI = good, association and signal is robust, so wireless frames use a shorter interval spacing to save time on the channel, thus increasing throughput. In an optimal radio environment that could. According to one embodiment, a wireless communication device includes a receiver configured to receive an orthogonal frequency-division multiplexing (OFDM) signal. The 802. 11n bands. Even at that I must be missing something with the modulation scheme, because the Nyquist max bitrate for 80Mhz and 256 QAM (8 bits per symbol) should be 480Mbps. 11ac is a wireless networking standard in the IEEE 802. INTRODUCTION S INCE its inception, IEEE 802. My mbps used to be at 100 - 300 now it's capped at 65, I tweaked my router settings to 20mhz, short guard interval, Channel 10, to reduce interference, my mpbs was capped still capped at 300, but days later, now its at 65, could this be a settings problem or isp problem? My English is bad sorry保护间隔（Short Guard Interval)：是OFDM符号中用于减少符号间干扰的时间。 ·在多径环境下，后一符号的前端有可能比前一符号的末端更快到达接收机，从而导致符号间产生干扰。Then you can also take advantage of 802. NOTE: The following information displays the MCS rate if the Short guard interval in 20 MHz mode setting in High-throughput SSID profile is either enabled or disabled:This paper, addressed the influence on the throughput of WLAN networks by controlling the SGI (Short Guard Interval) and enabling/disabling IEEE 802. 7), I saw the traffic which has been comunicating my router to and this baffles and concerns me, idk if im compromised or not. When deploying a wireless network in an environment with many obstacles, there will be diffraction, scattering and reflection. Compare the features and options with previous versions and other Fortinet products. Jun 11, 2017. 12-12-2017 10:35 PM. Determine whether the OFDM symbols adopt the short guard interval which is 400ns. HA heartbeat packets consume more bandwidth if the hb-interval is short. 11n specifies two guard intervals: 400ns (short) and 800ns (long). 5 Mbps for 20 MHz and 1147 Mbps for 40 MHz channel in 2. It’s generally recommended that you maintain a short GI. 1 summarizes the most recent records for high SE multicarrier transmission. MU-MIMO is short for Multi-User, Multiple-Input, Multiple-Output. Interval. However, if it’s too short, the amount of ISI will increase, and throughput will decrease. 11 ac/ax explicit transmit beamforming (TxBF)The invention relates to a switching method for a long guard interval and a short guard interval and a module thereof. Enabling the Short Guard Interval increases the Data Rate. SU/MU[0] Coding — A bit field that indicates if convolutional or LDPC coding is used for a single user or for user MU[0] in a multiuser scenario. The long Guard Interval (GI) and short Guard Interval (SGI) are functions built into OFDM that help to mitigate these effects. 11n MCS specification to see how this may affect throughput). 11n 针对 802. 11ac/n" and set "Channel width" to 40 MHz and enable "Short Guard Interval". The switching method comprises the following steps of: receiving first data symbols which comprise a cyclic prefix and valid data; generating second data symbols according to the cyclic prefix, wherein the second data symbols comprise. Support of the 400ns GI is optional for transmitting and receive. 5kbps × 3. 8. 2 of 4 μ s carry actual data, therefore data rate per subcarrier is 312. 25 KHz for 802. Select to enable the short guard interval. 11n amendment added support for an optional 40MHz channel. 11 {a | b} 11nsupport guard_interval {any | long} Configure the Reduced Interframe Space (RIFS) for the network by entering this command:. Short guard interval in 20 MHz mode. I accessed my fiber modem (It has RouterOS 7. So you're limited to 65mbit per spacial stream. An AP identifies any signal content received inside. Short guard intervals are possible with 802. 4. The guard interval prevents Inter-Symbol and Inter-Carrier Interference (ISI, ICI). • Short (400ns) — When an access point communicates with clients which support short guard interval, it will transmit with the use of a 400-nanosecond guard interval. The Beacon Interval value depends on the number of VAPs. Ensure to keep at least 6 dB lower value on 2. We would like to show you a description here but the site won’t allow us. 11n, the different rates are called the Modulation and Coding Scheme (MCS) index value, and the value defines how many streams are used. 11ac or 802. 11a/g radios use a 800 nanosecond guard interval. According to one embodiment, a wireless communication device includes a receiver configured to receive an orthogonal frequency-division multiplexing (OFDM) signal.