Cellular and WiFi networks have sometimes been seen as competitors, primarily in the wireless data market. However, they may be viewed as complementary services or even as a way to enhance coverage. Coverage continues to be a key reason cellular customers complain and switch service providers. Recently, wireless usage has increased due to competitive pricing and new entrants within the telecommunications industry.
In the context of this specification, the term cellular is used to denote wireless networks and services associated with 1G, 2G, 2.5G, 3G, and 4G networks such as CDMA, TDMA, GSM, UMTS, and others. The term cellular is also used to distinguish one form of wireless networks from other wireless networks such as WiFi. WiFi denotes IEEE 802.11 wireless networks.
Service providers that offer wireless services have increased the number of minutes included in voice plans and encouraged customers to “cut the cord” by moving away from their local exchange carrier to an all-cellular service for their mobile and in-home voice services. Programs that entice customers with free long distance service and unlimited usage plans on weekends and after 7 p.m. have clearly driven in-home usage of cellular voice services.
At the same time of cellular service increases, there has been a rapid growth of WLAN (Wireless Local Area Network) deployments within enterprises, hotspots, and homes, along with improvements in VoIP over WLAN access to provide high-quality voice service. Now, combined with the introduction of dual-mode handsets (Combo Phones) that can support both cellular (GSM, UMTS or CDMA) and WLAN, new market opportunities for service providers are being created. The ability of service providers to deliver a comprehensive, high quality voice service that converges a mobile and fixed-line infrastructure is considered a compelling product differentiator.
One way in which to capitalize on the convergence of mobile and fixed-line infrastructures is to develop a strategy for combining CDMA and WiFi networks, or combining any cellular and WLAN networks. This strategy would leverage customers with existing broadband data access for backhaul and WiFi access networks primarily within residential homes and small businesses. Providing consumers with a nationwide, competitive, mobile service along with in-building quality that is on par with traditional wireline voice services opens a new market opportunity.
The offering of combining various wireless networks has led to the use of an industry-wide term, fixed mobile convergence (FMC). FMC is used to describe the combination of WiFi and Cellular into a mobile handset. Various manufacturers and service providers are developing a dual band mobile handset or endpoint device to provide combined WiFi and cellular services. In addition, some service providers are combining the WiFi/cellular services with cable broadband services.
The offering of combined WiFi/cellular services presents some problems. One of the problems is that although cellular networks are typically secure, WiFi and similar networks are typically not secure. The cellular networks have reliable encryption capabilities that allow telephone calls and other services to traverse the cellular network between two endpoint devices. In many cases, this encryption is proprietary and provides a secure network. On the contrary, WiFi networks tend to provide an open access with relatively little or no security. There are no assurances for privacy for a call traversing a WiFi network. In addition, a service provider has little or no control over a telephone call or data session after it leaves a cellular network and enters into a WiFi network.
The Data Over Cable Service Interface Specification (DOCSIS®) standard defines interface requirements for cable modems (CM) and eMTAs (multimedia terminal adapters with embedded CM) for the customer premise equipment used for high-speed data distribution over cable television system networks. The inability to provide a level of QoS within the DOCSIS access network is a limitation. Without QoS within the cable access network all traffic will have to contend with existing data traffic including FTP, streaming media, e-mail, gaming applications and other emerging Internet applications competing for their share of bandwidth. VOP services require strict levels of QoS in order to perform on par with circuit-switched voice services. Voice traffic has two critical required characteristics, very low delay and very low jitter. Please note that VOP can include such technologies as VoATM, VoIP, VoWLAN, to name a few.
Interactive voice conversations must have low delay. The maximum acceptable delay is about 150 ms from ear to ear. Unfortunately, there are limits on what can be done in the network to reduce delay, especially when VOP services compete with typical IP data services for network resources. Development of the packet cable standards has provided cable service providers, known as MSOs, the ability to deliver a superior VOP service which leverages QoS in the DOCSIS network.
DOCSIS networks are configured to deliver shared bandwidth to broadband cable customers and are over subscribed by MSOs to gain network efficiencies. Developing packet cable and packet cable multimedia (PCMM) standards which can provide dynamic QoS triggers to the DOCSIS network-based service flows (types of data traffic) is key to creating high quality latency and jitter sensitive applications like voice, multimedia and IP video.
As a result of the envisioned problems, a solution is needed that allows customers to access multiple wireless networks in a data session including cellular and WiFi while also providing security of the data session. The solution should provide security of the data session when it is initiated, terminated, or transited through open access networks such as WLAN and in particular WiFi. More specifically, the data session should receive quality of service (QoS) when traversing through the open access network in order to maintain specific qualities that are received in cellular or circuit-switched networks.