Push to Talk Implementation, Operations and Technology Supporting

Push to Talk Implementation and Operations

Implementing and operating PTT is not a simple issue as there are many issues that must be considered and ultimately resolved/managed for optimal success including:

Voice Quality: The use of IP technology for PTT inherently ads the issue of voice quality of service (QoS), just as QoS is an issue with VoIP on fixed networks

Call-Set-up Time: The duration of time from the instance of selecting a user to engage in a PTT session to the time that one is able to initiate a conversation.

PTT Interoperability: Currently, PTT implementations are strictly proprietary based, creating a situation in which there is little or no opportunity for interconnection between PTT systems and thus no inter-carrier PTT communication for end-users.

Numbering Issues: For example, one decision point is to use of a single number (for both normal cellular and PTT) or a separate number for PTT calling.

Technology Supporting Push to Talk

At the core of PTT is an IETP standardized protocol known as Session Initiation Protocol (SIP) used for IP communications and Wireless Softswitch network infrastructure.

Being that it uses IP as a transport/bearer, PTT is highly dependent on the roll-out, expansion and improvements of 2.5G and 3G technology and infrastructure.

The Open Mobile Alliance (OMA) is working to standardize Push-to-Talk over Cellular (PoC) – see PTT Standardization (below).

Benefits of Deploying and Operating Push to Talk

Incremental Revenue

PTT represents incremental revenue to the wireless carrier, as it is an additional service that does not replace normal cellular mobile communications service, but rather is a VAS add-on to existing service.

Differentiation

Being a VAS, PTT represents a significant differentiator for both carriers that implement and optimize early as well as those that find clever ways to integrate PTT with other VAS services in ways that maintain differentiation even after PTT is more mature (for example: even after inter-carrier PTT is in place and optimized).

Cost Savings

Perhaps one of the greatest benefits that wireless carriers enjoy from PTT is the network cost efficiencies that are realized in at least two ways. Use of the underlying IP-based network with half-duplex transmissions has the advantage of both requiring less bandwidth (e.g. network and facility savings) as well as avoiding interconnection to the PSTN (e.g. savings against interconnection charges).