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Network and Infrastructure

Enhancing Wi-Fi to Better Serve the Campus Community

by S K Tsui

City University of Hong Kong has full Wi-Fi coverage in the entire campus, powered by over 2,800 Access Points (APs).  These APs are all Wi-Fi 5 (802.11ac Wave2) compatible.  Subsequent to a recent Internet bandwidth upgrade, the individual bandwidth control is unleashed.  In other words, users using Wi-Fi 5 compliance devices on campus can now enjoy much faster campus network and Internet connection when they are connected with CityU’s Wi-Fi service.  For a modern notebook computer equipped with two spatial streams (2 + 2), an average of 300 Mbps upload / download speed can be reached:

Wi-Fi-1.jpg

Moving Foward

Wi-Fi 6, also known as 802.11ax, is the latest generation of the Wi-Fi standard.  This new standard has many new features and improvements over the Wi-Fi 5.  The Computing Services Centre (CSC) has installed a few Wi-Fi 6 access points for evaluation and will use it for new deployment, particularly in crowded areas such as Lecture Theatres and classrooms.  Table below summarized the features of Wi-Fi 6 and its improvements over Wi-Fi 5.

  • Higher data rates – it delivers better throughput.  The maximum theoretical speed for Wi-Fi 6 is 9.6 Gbps as compared to the 3.5 Gbps on Wi-Fi 5 Wave 2.
    Wi-Fi Standard Maximum theoretical speed Frequency Bands
    802.11b 11Mbps 2.4 GHz
    802.11a 54Mbps 5 GHz
    802.11g 54Mbps 2.4 GHz
    802.11n (Wi-Fi 4) 600Mbps 2.4 GHz and 5 GHz
    802.11ac (Wi-Fi 5) 3.5 Gbps 5 GHz
    802.11ax (Wi-Fi 6) 9.6 Gbps 2.4 GHz and 5 GHz
  • Better performance in crowded areas – it uses OFDMA (Orthogonal Frequency Division Multiple Access) technology to serve multiple clients at once within a single channel and supports full-duplex MU-MIMO (multi-user, multiple input, multiple output) to allow several clients to perform uploading and downloading simultaneously. 
    Wi-Fi-2.jpg

    This is a major improvement over Wi-Fi 5 which allows only one client to send data to the AP at any one time.

  • Lower power consumption for Wi-Fi 6 devices – its new “target wake time” (TWT) feature enables wireless access points and devices to negotiate when to wake up their Wi-Fi radio and when to go to sleep.  This feature enables devices to significantly conserve power and improve battery life, especially useful for IoT devices.

  • Better network security - supports new security encryption using WPA3.  WPA3 provides a 192-bit security suite which greatly enhances Wi-Fi network security and makes it harder for hackers to break into the network.

Outdoor Wi-Fi Coverage

In addition to the performance enhancements, the CSC will be installing outdoor APs to improve and strengthen Wi-Fi coverage in outdoor areas, including:

  • Chinese Garden
  • Sky Garden of LAU and LI buildings
  • University Circle
  • Pathway between TYB and YEUNG buildings
  • Other selected open areas

The CSC dedicates to improve the University’s Wi-Fi service by accommodating the latest technology and, as always, to improve campus experience.  If you experienced any Wi-Fi connectivity issues on campus, you are most welcome to inform us the time and location via csc.servicedesk@cityu.edu.hk for our investigation and improvement actions.