Voice over Wi-Fi

With its native support in Apple’s iOS 8.0, Voice over Wi-Fi (aka Wi-Fi Calling) has suddenly gotten a lot of attention. With Voice over Wi-Fi, a mobile phone which used to be only limited to placing and receiving calls and texting when “cellular coverage” was present, can now use Wi-Fi to provide the same service!

Cisco Voice over Wifi Leader

Voice over Wi-Fi Benefits Everybody

Mobile Network Operator (MNO) can not only “offload” their data traffic to Wi-Fi networks but now can do the same with the voice traffic. Voice over WI-Fi allows them to also extend their services further and at much lower cost than with traditional cellular technology that rely on licensed spectrum. With Voice over Wi-Fi, MNO can easily deploy Wi-Fi access point or rely on already existing operational Wi-Fi networks. Businesses can now offer better voice coverage in their buildings by allowing their employees and guests’ phones to “roam” on their Wi-Fi network. You no longer have to take an awkward walk to the nearest window because the cellular coverage is spotty in the conference room, or miss a call because you were in the underground garage. With Voice over Wi-Fi, you can get great voice coverage everywhere you have good Wi-Fi—seamlessly and transparently.

That said, in order to provide a great Wi-Fi Calling voice experience you want a Wi-Fi network that has the technology to handle it properly. A single Wi-Fi call does not place a heavy data load on the network, but latency, jitter, and other applications on the network can affect voice quality.  Furthermore, when a Voice over Wi-Fi user moves from outside to inside a building while talking on his or her mobile device, handoff will occur between Access Points and can affect the user experience.

Cisco Has You Covered

Cisco is the networking leader with the most experience in Voice over Wi-Fi. Not only have we been designing call managers and Voice over Wi-Fi handsets for over a decade, but have also been optimizing our Wi-Fi Access Points, Wireless LAN Controllers, Switches and Routers to provide the best Voice over Wi-Fi experience possible, end to end. By using Cisco’s Wi-Fi Access Points and Wireless LAN Controllers as the infrastructure to handle your Voice over Wi-Fi calls, you are leveraging technology that is designed to deliver a High Definition Voice Experience (HDVX). These are some of the technologies a Cisco WLAN network with Cisco Aironet 3700 or 2700 Access Point Series has integrated in order to provide HDVX:

  • 802.11ac with 4×4 MIMO and 3 Spatial Streams: highest data rate and coverage area
  • ClientLink 3.0: increase Wi-Fi performance and range by up to 60%. Also significantly improve link stability for better call quality and reliability.
  • Optimized Roaming: intelligently assist Wi-Fi enabled phones when roaming between access points or to the cellular network
  • BandSelect: steer dual bands Wi-Fi enabled phones from the 2.4GHz band toward the faster 5GHz band
  • RF Turbo Performance: support a high density of  Wi-Fi devices with no performance degradation
  • CleanAir 80MHz. RF interference detection and mitigation optimized for 802.11ac’s wider channel bandwidths
  • Wi-Fi Multimedia Admission Control (WMM-AC): helps eliminates call drops when Wi-Fi network congestion occurs.

In an upcoming software release, Cisco will be introducing more features to improve even further the Voice over Wi-Fi experience, including:

  • Application Visibility and Control (AVC) for Wi-Fi Calling: automatically set the QoS (Quality of Service) to the highest level when a Voice over Wi-Fi call is detected
  • Call Admission and Control (CAC) for Wi-Fi Calling: for real-time delay-sensitive traffic such as voice, it is better to deny network access under congestion conditions than to allow traffic onto the network to be dropped and delayed, causing intermittent impaired QoS and resulting in customer dissatisfaction. CAC is therefore a deterministic and informed decision that is made before a voice call is established and is based on whether the required network resources are available to provide suitable QoS for the new call
  • 802.11v – BSS Transition management: Cisco WLAN will provide recommendations to the Wi-Fi phone on which Access Points will provide the best speed/stability based on signal strength and environment RF conditions.
  • Microsoft Lync Calls:  In addition to providing visibility of the status of Lync calls, the QoS can also be automatically optimized to enhance the call fidelity and improve the MOS score.

Follow us closely as we drive to expand our solutions and develop more value-added services—such as Voice over Wi-Fi—leveraging the existing WLAN infrastructure!

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Walt Shaw

Director, Product Management

Enterprise Networking Group (ENG)