Mobile VoIP
an attack on the mobile business value chain?
Since the danger that VoIP poses for the fixed network operators’ existing business models has finally been recognised, it seems just a matter of time before the increasing data transmission capabilities of wireless networks lead to a similar development in this market. Wireless LANs in hotels, at airports, on company premises and at home offer wireless data access with high bandwidths independent of cellular networks. The transmission costs per megabit using GPRS and UMTS are falling; HSDPA and EDGE are providing additional capacity. New broadband access methods with low latency, such as WiMax, Flash OFDM and also UTRAN TDD are already available on the market. Success for mobile VoIP at the same time poses a potential threat to the main source of income for mobile network operators.
Success factors for mobile VoIP
The increasing availability of DSL connections in the last one or two years has woken VoIP out of its slumber and pushed it into the limelight of public interest. The removal of the ‘last mile’ bottleneck provided a necessary precondition for the acceptance of VoIP as a real alternative for voice communication. This makes clear that besides the cost advantage, more factors determine the success of a mobile VoIP service offer. These factors include:
> Quality of Service – Quality and efficiency of the digital voice coding, protection against transmission errors, control and limitation of transmission delays, prioritisation of real time data in relation to background services in the access and transport network.
> Security aspects – prevention of fraud and illegal interception.
> Regulatory aspects – emergency functions, lawful interception, number plans for VoIP connections, geographic calling numbers.
> User friendliness – use of the available telephone infrastructure, "Plug&Play" of new infrastructure, availability, simple and transparent billing, additional services such as unified messaging or address books.
The challenges for mobile VoIP are greater than those facing VoIP using wired access. The existing radio transmission capacities are generally shared by a number of users, which means that additional measures are required for efficient transmission and to ensure the quality of service. High latencies, varying signal quality and interferences must be dealt with. Further complications come into play due to the handover of connections between different wireless protocols to enable widespread provision of the service. The problem of having to provide handsets which are attractive in both price and technical terms is also to be considered.
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