11n and 802. 6, or 3. In order to dissect the Guard Interval it is important to think of the signal transmissions from the viewpoint of the Time domain rather than the frequency domain. 4Ghz long guard interval. it enables the support of a short guard interval for the first station. Default. 4 GHz (30%) and 5 GHz (70%) Avoid low transmission rates (802. Jun 11, 2017. 11n amendment added support for an optional 40MHz channel. 27,538. 802. . Masukkan URL admin Indihome 192. A shorter DTIM interval could theoretically make your wireless devices use up their batteries faster, because they'd have to wake up more often for multicasts. Wi-Fi beacons are relatively short, regular transmissions from access points (APs) with a purpose to inform user devices (clients) about available Wi-Fi services and near-by access points. 8 µs—or even 1. Dengan memposisikan routers di tempat yang strategis, maka jangkauan wifi juga akan lebih maksimal. 11a/g. Use either the short guard interval (Short GI) of 400 ns or the long guard interval (Long GI) of 800 ns. 2 microsecond guard interval with the data packet area being increased 4x, or up to 12. Devices that take advantage of the phase 2 parameters (8 spatial streams, 160 MHz of bandwidth and 256-QAM 5/6 with a short guard interval) can achieve almost 7 Gbps. Generally, high-end wireless LANs offer the RTS threshold in radio network interface cards (NICs) and access points — the function is not available in SOHO or inexpensive home products. Router manufacturers support different versions of 802. 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. Note that option htmode should be set to either HT40+ (for channels 1-7) or HT40- (for channels 5-11) or simply HT40 . Dec 16, 2021. Guard Interval (GI) refers to the amount of time in between the transmission of frames. There are four options to append samples in the guard time. 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. Enabling a short guard interval can decrease network overhead by reducing unnecessary idle time on each AP. Figure 1-2 High-density and high-bandwidth scenarios. : Step 2 : Select the 11n Mode check box to enable 802. 8 μs. Use the VLAN pool when available. 64 QAM. 8 μs. 802. 1. 11n guard interval. 11n/ac/ax/be, the Guard Interval selection is 1/4, 1/8, or 1/16. So you're limited to 65mbit per spacial stream. Этот интервал помогает при. MU-MIMO only worked in . 11g, the Channel pulldown menu is displayed. 168. 11ac as the next WLAN standard, 802. 47 Gbpsのデータ. By reducing idle time in environments that aren’t very noisy, turning on SGI can increase wireless data rate by 11%. The available channels depend on which IEEE wireless protocol you selected in Band. 4GHz, tendrás peor rendimiento ;. 5. In another embodiment, the disclosure defines the guard interval for single channel transmission channel bonding and for MIMO transmission. 11b/g radios. A data frame, or simply called a “ frame ” is a package of data exchanged between wireless devices. MIMO configuration up to 4 x 4 can be employed. , Sub-carrier secara orthogonal dapat dilihat dengan dua cara, dalam domain waktu dan frekuensi. 400 ns long guard interval. 11be, dubbed Extremely High Throughput (EHT), is the next amendment of the IEEE 802. 11n only, you may. Gartner Glossary Information Technology Glossary G Guard Interval. It will build upon 802. 11ax, the sub-carrier spacing is reduced four times. 4Ghz long guard interval. OFDM. Date to Enable Radio (week days): This field defines the dates the wireless network is enabled. GI模式配置为short <AC> system-view [AC] wlan [AC-wlan-view] radio-5g-profile name default [AC-wlan-radio-5g-prof-default] guard-interval-mode short: 无线信号在空间传输会因多径等因素在接收侧形成时延，若数据帧之间间隔太短，容易和前后的数据帧形成干扰，而GI就是用来规避这个干扰的。Short GI: disabled – Short Guard Interval decreases the time between data characters being sent wirelessly. 11n outlined the idea of a short guard interval, decreasing. Indeed, the shorter guard interval evidently results in intersymbol interference (ISI) and intercarrier interference (ICI), but the gain offered by shortened guard interval may exceed the loss caused by interference. 11g network and the reported connection speed also fluctuates wildly,. 2. (ISI). Enter the following information: • Guard Interval: Choose either Long (800 ns) or Short (400 ns) that the security appliance will retry a frame transmission that fails. Best WI-FI Settings. 11ac tutorial covers WLAN 802. • AP Isolation Feature - If you want to confine and restrict all wireless devices connected to the network from interacting with each other, but still able to access the internet, enable AP. 11n data rate. tx_pkt_preamble. 93 Gbps ( using 160MHz bandwidth, 8 spatial streams, MCS9, 256QAM, with short guard interval) and coverage range of approx. Short GI for 80 (1 bit) and Short GI for 160 & 80+80 (1 bit) These fields are each set to 1 if the transmitter can receive frames transmitted using the short guard interval with the indicated channel bandwidth. 29_XIIA_KD . 125 KHz, compared to 312. 11ax technology. 11n added optional support for a 0. Guard Interval (T GI )Time Calculation The following table shows. The 802. 11 standard defines a few different interframe space periods that provide a safety. WiFi 101 Blog Asset Management Asset Management Tool. 11n you can choose between a short guard interval and a long guard interval. In normal 802. 11n, modulation and coding schemes (MCS) are used to determine the data rate of a wireless connection using high-throughput orthogonal frequency division multiplexing (HT-OFDM). cushion between frames. This better reduces the multipath effect and boosts Wi-Fi coverage. 2 - Mixed Preamble. ガードインターバル. an 80 MHz transmission sent at 256QAM with three spatial streams and a short guard interval delivers 234×3×5/6×8 bits/3. 11ac/n" and set "Channel width" to 40 MHz and enable "Short Guard Interval". Otherwise said, you should set a relatively short amount of time between the transmission of. About This Document. 11, the channel bandwidth was 20MHz with later amendments adding support for 5 and 10MHz bandwidths. IEEE 802. Guard Interval. 802. 11ax has three types of GI – the normal GI (0. 11a/g的GI时长为800ns，而Short GI时长为400ns，在使用Short GI的情况下，可提高10%的速率。 另外，Short GI与带宽无关，支持20MHz、40MHz带宽。 保护间隔（Short Guard Interval)：是OFDM符号中用于减少符号间干扰的时间。 There are three modes of wfb_rx: Local receiver -- I. 4GHz como para la banda de 5GHz. The available bands depend on the selected platform. RouterOS wireless complies with IEEE 802. 11n on 5GHz. 11n and 802. In the screen shot above you will notice that Short Guard Interval and Aggregation are both disabled. Enable/disable WiFi multimedia (WMM) call admission control to optimize WiFi bandwidth use for VoIP calls. A guard time is a short time interval that is added between the TDMA slots. 11ax has three types of GI – the normal GI (0. Better resiliency in outdoor environments is expected. I think the following command should force long/short guard intervals on the Device transmissions: iw [options] dev <devname> set bitrates [legacy-<2. 11acは、Wave1とWave2の2つの規格に細分できます。. Top. Version:V200R019C00. Guard Interval (GI) refers to the amount of time in between the transmission of frames. I forgot to mention enabling long preamble, which really helps with mobile wifi clients as they spin up from low radio power modes. UWB (Ultra Wide Band) is the PHY defined in IEEE 802. Wi-Fi 6 is higher density. In most of the cases clients negotiate with SGI-False (LGI) flag. The purpose of a guard interval is to introduce immunity to propagation delays, echoes, and reflections to which digital data is normally very sensitive. It has the following characteristics: Type: Control ( wlan. , Long Term Evolution (LTE), WiFi, etc. Example: Device (config)# ap dot11 5ghz dot11n rifs rx: Configures the Reduced Interframe Space (RIFS) for the network. 11n added optional support for a shorter 0. Using guard time requires extra time and energy, which is critical in wireless sensor networks operating on limited energy. 4GHz, but this is still often left as the long guard interval since some older devices have issues with a shorter guard interval. Namun, ada beberapa istilah yang berbeda. (config)# ap dot11 5ghz dot11n guard-interval long: Configures the guard interval for the network. type == 1) Sub-Type: 2 ( wlan. 15. 11n protocols is plot- ted for MCS values 1 to 8 for short and long GI in Figures 3 and 4 with channel. 4GHz,. 400 Mbps (two spatial streams at 40 MHz short guard interval) This is a full third faster than the comparable 802. 4GHz band supported channel bandwidths: 20MHz Y N 5 GHz band supported channel bandwidths: 20 MHz Y Y 5 GHz band supported channel bandwidths: 40 MHz Y Y 5 GHz band supported channel bandwidths: 80MHz Y Y Short/Long Guard Interval (400ns/800ns) Y Y 11ac Data rates – Up to 433. Use the guard-interval configuration mode command to configure the The 802. Setelah itu, ada beberapa pilihan dari menu network yang sudah terbuka. 802. Lebih lengkapnya, setelah memasang wifi tanyakan kepada teknisinya. 11 operation, the guard interval is 800 ns. The slower Wi-Fi devices can be slow from either long physical distance, weak signal strength, or simply being a. 11n you can choose between a short guard interval and a long guard interval. The 802. For example, wlanHTConfig('GuardInterval','Short') specifies a 400 nanosecond guard interval (cyclic prefix) duration. Nv2 wireless protocol supports short guard interval. This is a small but essential utility for any user of a Wi-Fi network, as long as they want to keep it safe. 8 μs. However, it will the take a long time for WLAN terminals to scan for Access Points in the area and to update RSSI and load information for already found Access Points. 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. 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). Wi-Fi 6. 11b 11nSupport guard_interval ? any Enable 802. 8 μs, to increase data rate 802. See Guard Interval for more details. You should be able to see it in a packet capture of the beacon. Like My Facebook Page ? i have a 10$ Course on Udemy!4. In order to dissect the Guard Interval it is important to think of the signal transmissions from the viewpoint of the. Jun 11, 2017. 2 µs) GI. Thereafter, forget SSID on WiFi clients and then test 5 GHz clients’ behavior. Short GI: disabled- Short Guard Interval decreases the time between data characters being sent wirelessly. OFDM. Go to solution. #2. 当设计802. 11n guard interval: Long (I can select Short but I thought to minimize interference and have it on Long). 11ax features. Lalu pilih menu Network > Wifi Control. N = short guard interval not used in the VHT-Data field. Al habilitar el Short Guard Interval, el Tiempo de Guarda se reduce a la mitad: 400 nanosegundos, con lo que la protección contra reflexiones se. Click Wireless > Advanced Settings. Higher the level, less sensitive the radio is and smaller the receiver cell size. Guard interval wifi hanya berfungsi untuk memperkuat sinyal wifi pada jarak dekat, namun tidak efektif dalam mengatasi interferensi gelombang wifi. Titik Penempatan Router yang Strategis. Systems, methods, and other embodiments associated with a single stream wireless communication with a greenfield preamble that uses a short guard interval are described. 11ac as long as additional features like WPA, WEP, AES encryption, Wireless Distribution System (WDS), Dynamic Frequency selection (DFS), Virtual Access Point, Nstreme and NV2 proprietary protocols and many more. (Cisco Controller) >config 802. any Enable 802. 11nsupport guard_interval {any | long} Configure the Reduced Interframe Space (RIFS). The guard interval in a typical 802. Wi-Fi radio test subcommands. 11n in its Draft 2 form in June 2007. - Change Radio 2 Band to "802. You should be able to change that by setting up steering on your AP/WiFi router. In your router setup. That interval can be reduced to 400ns by turning on SGI. Posted. 11n-2. The shortest interval (1/32) provides the lowest protection and the highest data rate; the longest interval (1/4) provides the highest protection but the lowest data rate. 11 {a | b} 11nsupport guard_interval {any | long} Configure the Reduced Interframe Space (RIFS) for the network by entering this command: config 802. 6 posts. In IEEE 802. ChannelsThe shortest interval (1/32) provides the lowest protection and the highest data rate; the longest interval (1/4) provides the highest protection but the lowest data rate. 256 QAM. The info I get from you are very reliable and on point. This gives a safe time between transmissions. The 802. MenuChoose Wireless > 802. e. 802. In IEEE 802. 11a/g的GI时长为800ns，而Short GI时长为400ns，在使用Short GI的情况下，可提高10%的速率。 另外，Short GI与带宽无关，支持20MHz、40MHz带宽。 保护间隔（Short Guard Interval)：是OFDM符号中用于减少符号间干扰的时间。There are three modes of wfb_rx: Local receiver -- I. 11n radio: ap#config terminal. WPA Encryption. 11n-2. Following are the major changes made in the 802. The purpose of a guard interval is to introduce immunity to propagation delays, echoes, and reflections to which digital data is normally very sensitive. (with short/long guard interval (GI)), 1 MHz channel bandwidth. 1. Default: Enabled. 4µs). Long Symbol Duration and Guard Interval A key characteristic of WiFi 6 is the narrower subcarrier spacing (78. The ratified version includes support for features such as short guard interval and frame aggregation. Short Inter-frame Spacing (SIFS), is the time interval required by a wireless device in between receiving a frame and responding to the frame. Jika sudah, maka pilih menu network yang ada di bagian layar Anda. Wi-Fi radio test subcommands. 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. Also used in TDMA transmissions. Beginning in privileged EXEC mode, follow these steps to set the 802. When the wireless radio is configured for 802. Change the wireless channel. Setting the 802. Pilih Wi-Fi control untuk masuk dalam pengaturan Wi-Fi yang Anda inginkan. 11a, 802. cfgHT = wlanHTConfig(Name,Value) sets properties using one or more name-value pairs. 11n guard interval: Long (I can select Short but I thought to minimize interference and have it on Long)Download A Field Guide to Secure Wi-Fi — Observations From Your Laptop and keep yourself up-to-date on ways to secure your Wi-Fi airspace 24/7 from unauthorized. Step 9: ap dot11 {5ghz | 24ghz} dot11n rifs rx. 11n specifies two guard intervals: 400ns (short) and 800ns (long). Powered by NRC7292 System-on-Chip from Newracom, SX-NEWAH is industry’s first IEEE 802. 11, the channel bandwidth was 20MHz with later amendments adding support for 5 and 10MHz bandwidths. 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 throughput. Enable or disable use of short guard interval (400 ns) in 40 MHz mode of operation. WPS (Wi-Fi Protected Setup) can help you to quickly and securely connect to a network. Você vai mexer com ajustes wifi de sincronização, de transmissão de pacotes, semáforos, e outras configurações de ajustes avançados do sinal Wi-fi. Ensure to keep at least 6 dB lower value on 2. Single radio/antenna devices do not support mimo and still having. Tunggu beberapa saat hingga Anda dihubungkan dengan tab menu yang baru. By using different SCS in 5G NR, different slot durations and TTIs are configurable. 11b/g used a longer guard interval than 802. The higher the MCS index is, the more throughput is supported by the corresponding modulation schema. When Short GI is enabled, the guard interval will be set as 400ns and this function will boost the performance about 11%. Pilih Wi-Fi control untuk masuk dalam pengaturan Wi-Fi yang Anda inginkan. 11 ac - Very High Throughput 2. 8 µs), double (1. 11a/b/g used a mandatory 800ns guard interval. Table 8. 11ac Wave2 (limited) 2. 11 guard interval The standard symbol guard interval used in IEEE 802. The invention relates to a switching method for a long guard interval and a short guard interval and a module thereof. By reducing the overhead of extra idle time between transmissions of two successive symbols, SGI helps to enhance the. I picked up a WRT-160N wireless router hoping to use it relieve the stuttering when streaming HD content over my WRT54G network. 11n, the guard interval has been reduced from 800 ns to 400 ns to boost the throughput. normally you can configure that the access point will use. เช่น WRT54GL Wireless G สัญญาณไปได้ไกลกว่า Router N หลาย ๆ ยี่ห้อในตลาดปัจจุบัน. Wireless Reliability - Guard Intervals. 4µs ลดเวลารอครึ่งนึง ทำให้ส่งข้อมูลได้มากขึ้นในระยะเวลาที่. Enable/Disable Short guard interval (GI) while transmitting the packet. 8 µs. Topic: Forcing Short and Long Guard Intervals. The shorter guard interval results in a. 25. Every client and access point on the same channel competes for time to talk. 125 KHz, compared to 312. 6 µs ,4x HE-LTF + 3. 11 standards, it provides complete support for 802. Configuring your beacons properly has a significant impact on how your network performs. 802. Umumnya, untuk mengatur jarak wifi bisa dilakukan dengan merubah persentasenya. 11n: A Survival Guide的第三章。 注释 6: 关于纠错码（Error-Correcting Codes）的更多信息, 参见802. The guard. Wi-Fi 6 isn’t faster than Wi-Fi 5. connecting using wireless, less than 2 meters away with direct line of sight, i got 20-60 mbs, varies from test to test. 11ac for different channel bandwidth and spacial streams. 802. The shorter guard interval results in a higher packet error rate when the delay spread of the channel exceed the guard interval and/or if timing synchronization between the transmitter and receiver is not precise. 11a/g radios use an 800 nanosecond guard interval (GI) between OFDM symbols. Deployments in the last couple of years are more likely to enable a short guard interval on 2. 11ax is no exception. These longer guard intervals help to prevent inter-symbol interference in outdoor environments and therefore improve coverage and performance. Remote forwarder -- Only capture a packets. 11 standards, it provides complete support for 802. Using guard time requires extra time and energy, which is critical in wireless sensor networks operating on limited energy. A Wi-Fi Alliance interoperability certificate indicates that a device is a/b/g/n certified. 11a/b/g requires guard interval (GI) to be 800 ns. This gives less time between. 11b/g/n > Network to open the Global Parameters page. การพิจารณาออกแบบ Wireless LAN (6) ทางเลือกสำหรับมาตรฐานต่างๆ การใช้งาน Guard Interval Guard Interval ซึ่งเป็นส่วนหนึ่งสัญญาลักษณ์ OFDM เป็นห้วงเวลาที่ถูกใช้เพื่อลดการ. 11ac物理层帧结构时，协议设计者会列出新的成帧需求。Disclosed are a method and a device for transmitting and receiving a frame using a short guard interval. • Enable Short GI - It is recommended to enable this function, for it will increase the data capacity by reducing the guard interval time. Occasional Visitor. 11ah Wi-Fi Solution for IoT Devices. 3. Fitur ini berguna untuk komputer yang dikonfigurasikan untuk memasuki mode tidur karena pesan DTIM akan memberi tahu klien bahwa router wireless memiliki informasi yang harus dikirim. 11 standard requires a guard interval (GI), a period of 800 nanoseconds, between each OFDM symbol that is transmitted to protect against ISI. UWB devices operate in license-free. Industry’s First 802. Wi-Fi 6 technology is all about better and more efficient use of the existing radio frequency medium. RxSOP determines the Wi-Fi signal level in dBm at which an access point's radio demodulates and decodes a packet. JP2016536910A JP2016540942A JP2016540942A JP2016536910A JP 2016536910 A JP2016536910 A JP 2016536910A JP 2016540942 A JP2016540942 A JP 2016540942A JP 2016540942 A. 11b/g/n /ax > Network to open the Global Parameters page. Previous. A scheme could be developed to work out whether a short guard interval would be of benefit to a particular link. This is a technical white paper that covers the features that are included in the emerging Wi-Fi Standard, 802. Wi-Fi 6 can also send the same amount of data to more devices at once. since 802. This should only be a temporary configuration change. Wi-Fi beacons consume airtime and erode the capacity of your network. Edit htmode options in the file /etc/config/wireless and restart the Wi-Fi AP to test various channel widths. 125,640. Choose Wireless > 802. orange pi voron. I am trying to configure 802. protected by a Guard Interval (short or long)* Note: The wider the channel, the more sub-channels available however, range is reduced because the same amount of poweris now spread across wider spectrum–so receiver has to work harder to hear the weaker signal. In this case study, we apply a formal approach to compute optimal safe guard times, i. 11n standard amendment was the introduction. Support of the 400ns GI is optional for transmitting and receive. If the beacon interval is long, maximum capacity in the Access Point is achieved. 8µs) and short GI (0. 11n supports using two guard intervals (short = 400 ns or long = 800 ns). In this video you will learn why and when to use wifi short guard interval in your FortiAP to increase throughput up to ten percent , but use it carefully as it can also decrease throughput in places where you have many physical obstacles . 802. Auto is the default channel setting, and it displays the. 11n you can choose between a short guard interval and a long guard interval. 3A Other languages German (de) French (fr) Other versions. Beacon Interval - Sets the amount of time between beacon transmissions in milliseconds. For 802. 1 Channelization When the OFDM PHY was introduced to 802. The CPE disconnected with control frame timeout and does not connect again. We would like to show you a description here but the site won’t allow us. 4 GHz and 5 GHz) and Wi-Fi 6E (6 GHz), is an IEEE standard for wireless local-area networks and the successor of Wi-Fi 5 . Yes, 802. 11n does not only support an 800 nanosecond guard interval, but also support a shorter 400 nanosecond guard interval. This example shows how to set a long guard interval on a 2. 25 KHz for 802. 1. In the capsman config that's being provisioned out just set the one ssid and vlan mode tagged with the base vlan for the default clients. In two radio devices, both radios cannot use the same band. config wireless-controller wtp-profile edit guest_prof config platform set type 220B. 11n/ac, where the value of the guard interval is set to 400ns instead of general 800ns. I assume you mean Short Guard Interval (SGI) when you say GI? If so, with other vendors that I've worked, I've been able to enable/disable SGI across all of their APs that I've worked with (which is more extensive with some vendors that others). Following table describes 802. Menambah Konsumsi Daya Baterai. 11n dan TDMA. By Daniel E. Short guard interval time is 400ns, which is half of what it was previously. The guard interval is the period in nanoseconds the radio listens between packets. 15. 11ac, short guard interval ( 400 ns) is introduced, while the default value of GI is still set as 800 ns. 1 Insight managed wifi 6 ax1800 dual band access point 1 Models 1 User manual 3 Contents 8 1. Two settings are available: short (400ns) and long (800ns). In Wi-Fi 6 or 802. 2. PLCP preamble field, composed of 10 repetitions of a "short training sequence " and two repetitions of a "long training sequence" preceded by a guard interval (GI). As discussedDoes anyone know where you can configure short/long Guard Interval (SGI / LGI) on SmartZone controlled APs?. This is horses for courses as it depends on your situation - remember the 2. 11ac as long as additional features like WPA, WEP, AES encryption, Wireless Distribution System (WDS), Dynamic Frequency selection (DFS), Virtual Access Point, Nstreme and NV2 proprietary protocols and many more. Wireless radio configuration. Monte Carol simulations are applied to evaluate. 11a/n /ac or 802. Header part consists of 24 bits which is always BPSK modulated. Mode. Otherwise said, you should set a relatively short amount of time between the transmission of. Maximum Number of Total Space Time Streams (Nsts,total)In a Wifi 802. The first 8 modes correspond to short guard interval disabled and channel bonding disabled. 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%. 4Ghz any to allow either short or long guard interval long Enable 802. I picked up a WRT-160N wireless router hoping to use it relieve the stuttering when streaming HD content over my WRT54G network. Spatial Streams VHT MCS Index Modulation Coding Rate 20 MHz Data Rates (Mb/s) 40 MHz Data Rates (Mb/s) 80 MHz Data Rates (Mb/s) 160 MHz / 80+80 MHz Data Rates. 11ac will include*Edit: Preamble Type: Long, unless your devices are very close to the router/extender/mesh node they're attached to, then try Short. This is kind of half right. 11 {a | b} 11nsupport rifs rx {enable | disable} Save your changes by entering this command: save config Short guard interval vs long? : r/HomeNetworking View community ranking In the Top 1% of largest communities on Reddit Short guard interval vs long? Which is better? I saw. 3 Gbpsのデータレートをサポートします。. Figure 33: 800 nanosecond GI (long guard interval) Long Guard Interval – 802. RE: Short Guard Interval - 20MHz. Table 1: RSSI Reference Values. Regards, ParikshithA silent guard interval would likely increase PAPR (peak to average power), which requires a sender capable of more dynamic range (without clipping or generating power supply noise, etc. e. These longer guard intervals help to prevent inter-symbol interference in outdoor environments and therefore improve coverage and performance.