In a wireless network environment, typical transmission distances can reach up to 300 meters in open spaces and 100 meters indoors. However, the practical transmission range is approximately 50 meters, which may decrease depending on environmental conditions. There are many factors affecting wireless signal coverage, such as building blind spots, structures, and antenna positioning. When using wireless network products, issues like weak signals, slow connection speeds, intermittent connections, and frequent disconnections often arise, leading to unstable connectivity—even when the computer is right next to the router (or base station, AP). This article by Master Mantou will briefly outline how to address the aforementioned issues.
The following are the factors affecting wireless networks:
Signal interference is not easily encountered in typical office or open spaces; it is more common in home environments. When this occurs, check the surrounding environment for objects that emit strong electromagnetic waves, such as microwaves or induction cookers. If found, it is recommended to keep the wireless router or computer away from such objects to effectively avoid signal interference.
In a wireless environment, signal reception can be affected by building structures, antenna orientation, router positioning, and data load, which can lead to poor wireless transmission quality. When encountering these situations, consider the following suggestions:
- Change the Router's Position: Ensure that there are not too many obstacles between the wireless router and the computer. Ideally, the computer should have a clear line of sight to the router. The more barriers there are, the weaker the signal. Metal materials greatly impact this, such as reinforced concrete walls or iron doors.
- Antenna Adjustment: First, check the antenna's position to see if any objects block the signal. If so, adjust the antenna to a position where both the router and computer can effectively receive signals. Note that antennas come in omnidirectional and directional types. Most wireless routers use omnidirectional antennas; if adjusting does not improve reception, consider replacing or adding an external antenna.
- Replace or Add Antennas: Signal range can be extended by replacing the antennas to increase transmission distance. Note that changing the antenna can only increase distance, not improve penetration through obstacles.
- Omnidirectional Antennas: These do not require a specific directional placement and emit signals in a 360-degree horizontal pattern, providing a wide coverage area but a shorter transmission distance.
- Directional Antennas: These require a specified direction, with a horizontal signal emission angle of about 10 to 30 degrees, providing narrow coverage but longer transmission distances.
- Increase the Number of Routers: If the distance between two connection points is too long, or if there are barriers between floors, adding more routers can extend the distance and improve signal transmission. However, keep in mind potential bottlenecks and the materials between floors.
The signal penetration ability can degrade depending on the type of medium. Metal can nearly completely block signal transmission. Therefore, in wireless configurations, avoid placing obstacles between the router and the computer to ensure smoother wireless transmission.
The 2.4GHz frequency band in the ISM band is widely used (e.g., by microwaves and Bluetooth), which can interfere with Wi-Fi and slow down speeds. The 5GHz band has less interference. Dual-band routers can operate on both 2.4GHz and 5GHz, but devices (computers, tablets, smartphones) can only use one frequency band at a time.
Before planning a wireless network, it is essential to understand the types of wireless network chips used in routers, which refers to the types of Wi-Fi.
Currently, Wi-Fi is divided into six generations, described as follows:
- First Generation: 802.11, based on the original IEEE 802.11 standard established in 1997, only uses the 2.4GHz operating frequency and achieves a maximum speed of 2Mbit/s. It has been phased out of the market.
- Second Generation: 802.11b, only uses the 2.4GHz operating frequency with a maximum speed of 11Mbit/s. It has been phased out of the market.
- Third Generation: 802.11g/a, operating at 2.4GHz and 5GHz frequencies respectively, with a maximum speed of 54Mbit/s. It has been phased out of the market.
- Fourth Generation: 802.11n, can operate at 2.4GHz or 5GHz, achieving speeds of 72Mbit/s and 150Mbit/s under 20 and 40MHz bandwidths, respectively. It is gradually being phased out of the market.
- Fifth Generation: Based on IEEE 802.11ac, known as Wi-Fi 5, with bandwidths of 20MHz, 40MHz, 80MHz, 80+80MHz, and 160MHz, operating on the 5GHz frequency band, with up to 8 spatial streams and a maximum modulation of 256-QAM, achieving speeds of up to 6.9 Gbit/s. The certification program is "Wi-Fi CERTIFIED ac."
- Sixth Generation: Based on IEEE 802.11ax, known as Wi-Fi 6, supporting bandwidths of 20MHz, 40MHz, 80MHz, 80+80MHz, and 160MHz, operating on both 2.4GHz and 5GHz frequencies, with up to 8 spatial streams and a maximum modulation of 1024-QAM, achieving speeds of up to 9.6 Gbit/s. The certification program is "Wi-Fi CERTIFIED 6."
As the first and second generations have been completely phased out, we will start the introduction from the third generation.
The 802.11g standard, formally known as IEEE 802.11g-2003, is a revision of the original 802.11 standard at the physical layer. It operates on the 2.4G channel and has a physical layer speed of up to 54Mbps. This standard has been widely applied globally. Relevant modifications have been integrated into IEEE 802.11-2007 and subsequent versions, becoming part of the 802.11 protocol.
The 802.11g standard operates on the 2.4G ISM frequency band and utilizes Orthogonal Frequency Division Multiplexing (OFDM) modulation, unlike the original 802.11 and 802.11b standards, which is similar to the 802.11a standard, allowing for a maximum speed of 54Mbps. In terms of medium access control, the standard adopts Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA), similar to other standards. Considering the overhead of the CSMA/CA protocol, the maximum throughput between 802.11g devices can reach 31.4Mbps. However, since products like microwaves, Bluetooth devices, and ZigBee operate in the ISM band, 802.11g devices may be subject to interference from other devices.
Due to the market demand for high-speed wireless transmission, 802.11g devices were widely deployed in January 2003, even before the official release of the 802.11g standard. 802.11g devices are backward compatible with 802.11b networks. However, the presence of 802.11b devices can slow down the entire 802.11g network's throughput.
IEEE 802.11n-2009 is a revision of the IEEE 802.11-2007 wireless LAN standard. Its goal is to improve the shortcomings of the previous two wireless standards, including 802.11a and 802.11g, in network traffic. Its maximum theoretical transmission speed is 600Mbit/s, a significant increase from the previous 54Mbit/s, with extended transmission distances. In January 2004, the IEEE announced the formation of a new unit to develop the new 802.11 standard, which was officially approved in September 2009.
Subsequent research on 802.11n is being conducted under the IEEE 802.11ac draft, expected to be officially released in February 2014, promising 8xMIMO, a maximum bandwidth of 160MHz, and a theoretical speed of up to 866.7Mbit/s.
802.11n can operate on both 2.4GHz and 5GHz, with a maximum speed of 72Mbit/s and 150Mbit/s under 20 and 40MHz bandwidths, respectively. However, some devices may only allow 40MHz bandwidth to be used under 5GHz, such as MacBook. If a user purchases a router that only supports 2.4GHz, they will only achieve 72Mbps, which is the maximum speed under 20MHz bandwidth.
IEEE 802.11ac, commonly known as 5G Wi-Fi (5th Generation of Wi-Fi), is a wireless LAN communication standard that operates through the 5GHz band. Theoretically, it can provide a minimum bandwidth of 1Gbps for multi-station wireless LAN communications or at least 500Mbps for single connection transmissions.
At the end of 2008, the IEEE 802 standards organization established a new group to create a new standard to improve the 802.11-2007 standard, which includes establishing standards to enhance wireless transmission speeds, allowing wireless networks to provide transmission performance comparable to wired networks.
802.11ac is the successor of 802.11n, adopting and expanding the air interface concepts derived from 802.11n, including wider RF bandwidth (up to 160MHz), more MIMO spatial streams (increased to 8), multi-user downlink MIMO (up to 4), and high-density modulation (reaching 256QAM).
Protocol Frequency (GHz) Bandwidth (MHz) Rate per Stream (Mbit/s) MIMO Support 802.11b 2.4 20 1, 2, 5.5, 11 N/A 802.11g 2.4 20 6, 9, 12, 18, 24, 36, 48, 54 N/A 802.11n 2.4/5 20 7.2, 14.4, 21.7, 28.9, 43.3, 57.8, 65, 72.2 4 40 15, 30, 45, 60, 90, 120, 135, 150 802.11ac 5 20 Max 87.6 8 40 Max 200 80 Max 433.3 160 Max 866.7
Wi-Fi 6 is a significant upgrade over previous generations. While users may not immediately notice a difference, the changes introduced by Wi-Fi 6 consist of many incremental improvements that collectively add up to a substantial upgrade.
IEEE 802.11ax is the wireless LAN standard known as Wi-Fi 6, also referred to as High Efficiency Wireless LAN (HEW).
The Wi-Fi Alliance launched the Wi-Fi CERTIFIED 6 certification program on September 16, 2019, and on January 3, 2020, it designated IEEE 802.11ax operating in the 6GHz band as Wi-Fi 6E.
802.11ax supports all ISM bands from 1GHz to 6GHz, including the currently used 2.4GHz and 5GHz bands, and is backward compatible with a/b/g/n/ac. The goal is to support indoor and outdoor scenarios while improving spectrum efficiency. Compared to 802.11ac, it offers a fourfold increase in actual throughput in dense user environments, a 37% increase in nominal transmission rates, and a 75% reduction in latency.
Faster Wi-Fi means that Wi-Fi 6 can provide greater bandwidth, thereby accelerating upload and download speeds (or throughput). As file sizes continue to grow and streaming high-quality videos and large amounts of data for online gaming demand more data, transmission speeds are becoming increasingly important. Gamers who stream live on Twitch while playing need considerable bandwidth and a reliable, stable connection.
As a result, many gamers and content creators still connect directly to the router or network switch via Ethernet cables rather than relying on the flexibility offered by wireless networks. Wi-Fi 6 brings wired and wireless signals closer to parity, allowing more users to break free from the constraints of fixed wired connections to their modems.
So how fast is Wi-Fi 6? While it’s crucial to consider numbers, Wi-Fi 6 can theoretically offer maximum throughput of up to 9.6 Gbps across multiple channels (compared to Wi-Fi 5's 3.5 Gbps). However, this is only the theoretical maximum; actual speeds may not reach these figures due to various factors, including the overall internet connection speed, which can impact overall performance. Nevertheless, devices equipped with Wi-Fi 6 can still enjoy relatively fast speeds.
If you use a Wi-Fi router with a single device, the maximum potential speed of Wi-Fi 6 should be about 40% higher than that of Wi-Fi 5. Wi-Fi 6 achieves these increased data transmission speeds through various technologies, including more efficient data encoding and the ability to reasonably utilize wireless spectrum with more powerful processors.
Wi-Fi 6 also enhances speeds by handling large amounts of network traffic more efficiently. For gamers, this means faster game downloads, better upload speeds for streaming games, up to 75% less latency, and more reliable media multitasking.
Compared to five years ago, it is clear that most households now have more Wi-Fi-enabled devices. From smartphones and tablets to TVs and IoT devices such as smart thermostats and doorbells, almost everything can connect to a wireless router today. Wi-Fi 6 allows for better communication with multiple devices that simultaneously need data, managing traffic prioritization more efficiently among these devices. One of the methods for achieving this is through the use of Orthogonal Frequency Division Multiple Access (OFDMA). OFDMA divides channels into subcarriers, allowing multiple endpoints (devices) to transmit simultaneously. Wi-Fi 6 routers can transmit different signals within the same transmission window, enabling a single transmission to communicate with multiple devices without each device having to wait for the router to service other data in the network before processing its own.
In older Wi-Fi versions, devices attempting to connect to the network followed a "listen before talk" protocol, meaning all devices had to "listen" for any noise on the channel before transmitting data. If there was any noise on the channel, even from a distant network, these devices had to wait until the channel was clear before transmitting to avoid potential interference. OBSS (Overlapping Basic Service Set) allows access points to utilize "colors" to identify networks. If they detect other traffic on the channel but with a different network color, the device can ignore that traffic and continue with its own transmission. This helps to enhance reliability and improve latency. OFDMA, combined with OBSS, facilitates more effective communication in crowded networks. As more devices utilize Wi-Fi, these strategies will help maintain connection speeds and stability.
Another technology enhancing Wi-Fi 6 is beamforming. This sophisticated-sounding data transmission method is relatively straightforward. Rather than broadcasting data in all directions, routers detect where requesting devices are located and send localized data streams in that direction. Beamforming is not a new feature for Wi-Fi 6, but its effectiveness has improved in this generation. When combined with other technologies such as OFDMA and OBSS, beamforming helps make Wi-Fi 6 faster.
Wi-Fi Protected Access (WPA) is a common Wi-Fi security protocol that uses passwords for encryption. Anytime someone wants to log into a Wi-Fi network, they must enter a password—that's WPA at work. WPA2 has long been the standard, but with the advent of Wi-Fi 6, things are changing. One of the most significant improvements is the implementation of the Dragonfly Key Exchange system (also known as Simultaneous Authentication of Equals, SAE) to enhance password security. This authentication method utilizes a more complex approach to establishing a handshake with the Wi-Fi network, making passwords more difficult to crack. This additional security layer, combining stronger encryption methods, means that Wi-Fi now offers more robust security options than ever before.
This extra security layer is an excellent example of how Wi-Fi 6 enhances operations without negatively impacting the user experience.
Another forward-looking development incorporated into Wi-Fi 6 is Target Wake Time (TWT), which has the potential to increase battery life for certain devices. This technology enables better communication between routers and devices regarding when to enter sleep or wake states. By effectively communicating with the device's Wi-Fi radio and only activating it when needed, your devices will spend less time and power searching for wireless signals, thus enhancing battery life.
Wi-Fi 6 provides significant enhancements, so you may wonder what you need to take advantage of this new communication protocol. The most critical upgrade you need is to purchase a Wi-Fi 6 compatible router. Most manufacturers now offer routers with Wi-Fi 6 capabilities, providing many options.
You will also need devices that support Wi-Fi 6. While Wi-Fi 6 is backward compatible with older 802.11ac (Wi-Fi 5), you still need devices that support Wi-Fi 6 to fully benefit from all the features listed above. As Wi-Fi 6 becomes standard in the coming years, newer devices will begin to incorporate this technology and become the norm.
Wi-Fi 6 will significantly impact how we interact with wireless devices. Faster speeds, better traffic prioritization, and enhanced security collectively represent a significant step forward in wireless network technology. Whether you're gaming, working, or simply streaming videos, upgrading to Wi-Fi 6 is worth considering.
The following are suggested key points for wireless network planning.
The emission range of wireless network signals is vertical to the antenna. For typical single-story homes, the antenna should be vertical to the horizontal plane. For multi-story buildings, the antenna can be placed parallel to the horizontal plane to cover wireless signals to other floors.
The ideal antenna emits signals evenly in all directions, providing equal signal strength at the same distance. Unfortunately, current technology cannot produce such antennas.
Another commonly used antenna is the dipole antenna. Compared to the ideal antenna, the dipole antenna exhibits varying signal strengths at the same distance. In some areas, the signal strength may be higher, while in others, it may be lower. Based on the dipole antenna's strongest signal point (belly) compared to the ideal antenna, it is found that the dipole antenna's signal strength is 1.6 times stronger, equivalent to a gain of 2.15dBi (i.e., compared to the ideal antenna). In other words, a dipole antenna has a gain of 2.15dBi.
High dBi antennas can expand signal range; the higher the dBi, the better the effect. If the antenna of the wireless router you're using is underperforming, consider replacing it with a higher dBi antenna.
In the 2.462GHz band, there are a total of 11 channels, each spaced approximately 5MHz apart. Although there are ±22MHz energy limits according to spectral shielding standards, which mean that transmitted signals weaken with different frequency bands, there is still some interference. To maintain good connections, it's best to stagger channels among the 11 options, preferably using channels 1, 6, and 11.
Enabling the QoS filtering mechanism can affect the performance of wireless routers, reducing the number of packets transmitted per unit of time. If you have multiple computers, tablets, or mobile devices using wireless networks, it is advisable to disable QoS filtering or use a router with a more powerful (higher-grade chip) performance.
This is an interesting point; theoretically, it should not be faster, but testing shows otherwise, contrary to general perception. The reason is that consumer wireless routers are often very cheap, and many activate Wi-Fi functions indiscriminately, leading to an abundance of wireless base stations that cause congestion in the 2.4GHz band. 802.11n can operate in the 5GHz band, which is less congested due to its higher cost and lower prevalence. However, the prerequisite is that other wireless network devices (computers, tablets, smartphones) must also support 5GHz operation.
Most weak electric boxes on the market are made of metal, and placing a wireless router inside will reduce performance, as metal can interfere with wireless signals. If you cannot avoid placing the wireless router inside the weak electric box, at least extend the antennas outside the box.
蘊藏許多助人的知識與智慧。