Abstract
VOIP (Voice over internet Protocol) technology has come a long way since the IEEE (Institute of Electrical and Electronic Engineers) in 1974, published the paper that was to herald a new frontier into the unchartered waters of telecommunication. The paper was titled “A Protocol for Packet Network Interconnection.” Several major developments have taken place due to research and development efforts by researcher and academicians worldwide. The impact of VOIP is being felt by everyone especially businessmen and companies. They are demanding for a cut in communication costs by cellular service providers. The introduction of VoIP in cellular technology is now threatening the major players in the telecommunication industry as well as making it easy for everyone to communicate despite the geographical distance that may be separating them. Communication is a vital part of human life. Several milestones have been achieved in the pursuit of its development. Since the early days of smoke signals as a means of communication, man has always been at the forefront of developing better ways of living (Radhaman 89).
Purpose
The Purpose of this paper is to introduce the background of the architecture of VOIP over cellular network and its future with regard to emerging technologies such as 2G, UMTS (Universal mobile telephone system), and 4G which are the current technologies that are being employed by mobile service providers. It is hence the goal of this paper to investigate which technology is best suited for mobile VoIP. As we all know that there is loss of packets during transmission and when we are talking of voice communication, errors cannot be afforded. Voice communication is more sensitive than data communication and it is this reason that error correction techniques have been integrated into the systems.
Background Information
Voice over Internet protocol has undergone various implementations that have enabled it to integrate with other communication technologies. These implementations consist of H.323, is widely used in conferencing of both video and voice, the protocol is used by IP networks worldwide. Another protocol that has participated in the development of the VOIP is IMS (IP Multimedia Subsystem) which is responsible for the structure of IP multimedia services. It was originally formulated for the purpose of delivering Internet and services related to it over GPRS network which at the time was the new technology. MGCP (Media Gateway Control Protocol), which is responsible for the handover operations between the present gateways. Public switched networks can also work hand in hand with VoIP through this protocol. Media streams can be modified to involve also unicast and multicast sessions (Radhaman 90). This means that the as many members of a conversation can be involved. This protocol is considered a signaling protocol; and was created by Henning Schulzrinne and Mark Handley. The last protocol that has been instrumental in the development of VOIP is Real Time Transport Protocol, which describes the format of an IP packet in the delivery of multimedia over the internet. Development of VoIP has undergone rapid but successful transformations to make it the communication technology of choice among companies and individuals with preference to lower costs. Although not fully embraced by the public, the future is bright for the VoIP and its impacts are yet to be felt by all.
Components of VOIP
VOIP has received the full adoption by consumers and this is manifested through the uptake of VOIP services offered by broadband access services providers. These companies offer normal services such as domestic and International calling at very low prices. Many of these firms offer services at a flat rate that is normally paid before or after the subscription period. There are various ways in which consumers may access VOIP services from the service providers. They can use an analogue telephone adaptor which is attached to an IP network that can also be connected to the jack of the phone so as to get the services that are the same as the traditional and existing services that are offered by PSTNs. There are also companies that provide the customer with hardware in the form of VOIP phones. This technique does not need one to have computer as the customer is connected openly to the network via Ethernet or WiMax. The third and final way that VOIP services can be provided to the customer is through the use of software in the form of soft phones. A soft phone can be installed in a computer and this allows the subscriber to call without the need for one to purchase extra hardware apart from the microphone and earpiece. Through VoIP, I.P packets containing voice communication is transmitted to the destination are channeled to the user’s hardware (Markova, 52).
Current architecture
One has to have a mobile phone that has dual mode features in order for them to enjoy the benefits that VOIP brings. A dual mode mobile phone is able to make VOIP calls while at the same time able to make calls to other circuit switched networks. A dual mode phone is able to perform a soft switch between a cellular network and a Wi-Fi network. These phones are however not easily acceptable by many mobile phone service providers as it reduces their revenues as the phones allow the subscribers to by pass their networks.This makes the calls very affordable. One has to just activate the SIP (Session Initiation Protocol) client from the phone (Radhaman 102). VOIP can also be offered to corporate and small sized companies wanting to cut communication costs. Many companies are integrating their telephone systems together with their network resources in the form of bandwidth in order to control phone costs. It is now easier for individual companies to communicate as the evolution of software has meant easier and faster upgrade of servers that are used for VOIP services. What took days or weeks for maintenance people to do is now taking a few minutes and can even be done from a remote location. This is presenting other specialists to concentrate on other tasks that are more critical towards the organization. Historically it would require one too purchase hardware such as new PBX systems in order to upgrade. These days one has to just download and install the update needed. This has also eased maintenance work as devices to be monitored and maintained become fewer and far less bulky. Using specialist software from manufacturers one can monitor the network for faults and hence come up with better diagnostics measures that will be able to resolve the issues in an efficient way.
Comparisons between Technologies
If VOIP is to migrate from one technology to another, we must investigate the characteristics and distinctive technologies that make up the different categories of cellular technology. Various technologies have different handling capacities when it comes mobile VoIP, as we can also see that there are several issue that exists. All these have the potential of degrading voice quality during communication.
Mobile VoIP as it is currently known encompasses the use of the normal cellular hand set in the initiating of calls within the internet. The 2G network is the pioneer technology that led to the widespread adoption of mobile telephony all over the world. Although there have been developments in technology, 2G remains the basic technology for cellular communication. Mobile VoIP cannot however work under 2G. When it comes to voice communication, reliability and quality remain the standard to which a network can be judged. For mobile VoIP over 2G, the quality is low as there is the ever existent competition between voice and data traffic hence making it impossible for voice to be carried reliably to the other party.
Despite efforts by service providers to block, VoIP calls on their networks, owners of 3G phones are able to make calls in areas where Wi-Fi networks are available. Such areas could be in hotels, or café shops. These service providers are quickly coming to the realization that allowing VoIP calls over their networks boosts their brands and also maintains subscriber loyalty. 3G technology has been able to counter the issue of latency that is present with 2G technology. VoIP has up to the recent times been restricted to places where there is Wi-Fi, however with the acceptance of service providers this is slowly changing as now subscribers can now use VoIP in all areas. Voice and data speeds are increasing as more research and technology is carried out on how to reduce latency which is described as the interruption encountered by packets during transmission. Research has also focused on increasing more codec for better sound quality. The spread of HSDPA (High speed downlink packet access) phones by subscribers will lead to better quality being experienced in VoIP calls. Such kinds of phones are able to integrate compression technology y that allows packets to be transmitted much faster from source to destination. However these phones are not easily obtained due to the cost of each unit. Adoption of such phones should be encouraged in order to boost the spread of mobile VoIP.
4G. technology is expected to fully integrated into existing networks after 2012 however there are countries who have already adopted the technology. 4G promises better and faster speeds and less cost for service providers who are intending to offer VoIP calls to their subscribers. 4G is a representation of the next generation technology after 3G.WiMax and Long-term Evolution (LTE) are part of this technology. 4G essentially utilizes frequency domain equalization. These techniques have replaced previous technologies such as the spread spectrum technology and IS 95. Orthogonal Frequency-Division Multiple Access (OFDMA) in 3G is replaced with a combination of dynamic channel allocation and channel dependent scheduling. Long term technology promises fast upload and download speeds. Mobile WiMAX offers rates of 128 megabits per second for the downlink of packets and upload speeds of 56megabits per second for upload. The speeds for WiMax are defined within the 20GHz range. Another constituent for 4G is Ultra Mobile Broadband which promises data speeds of 275 megabits for downstream communication and 75 megabits per second for upstream communication (Syed 66). Many mobile service providers in developed nations are at the trial phase as they continue to roll out 4G services all across Europe and North America. This however is not to say that developing nations are not rolling out the technology. Many countries in the developing nations have stated 2012 as the deadline by which full adoption of 4G. This technology promises faster data rates and voice transmission. Multimedia services will be supported and it will be possible for individuals to make video calls to one another. 3G failed to make these possible because of the high latency rates that packets encountered during transmission.
Challenges facing Mobile VoIP
The challenges facing mobile VoIP are numerous starting with acceptance by most service providers in allowing VoIP calls within their network. This is because of the perceived threats that are brought about by this technology. While some have woken to the realization that mobile VoIP is here to stay, there are still some defiant providers out there. Mobile VoIP also faces challenges on the technological front as we have seen that 3G is not able to provide the much touted speeds that were clearly promised. Issues of latency and sound quality have plagued the spread of VoIP over 3G as customers have been complaining of low signals and service interruption have been experienced on a wide scale in some of the networks. Others have been complaining about quality of service issues such as when the call initiated is cut off when roaming Application developers have also been slow in developing solutions targeted for mobile VoIP this has slowed down its adoption by users. Service providers also have the task of setting up the right infrastructure and coming up with the best price for both their business and for customers. Although it is not cheap laying new infrastructure to cater for mobile VoIP, the returns to both the investors and subscribers will be seen in the near future when users start embracing the technology for everyday use.
Phone manufactures have been slow in integrating appropriate protocols for supporting mobile VoIP. Manufacturers have assembling phones based on the 3G technology and only few have embraced adapting to new technology. However these manufacturers are still pricing the models at a costly price hence locking out the majority of users who would have benefited from mobile VoIP. Protocols such as session initiation protocol are still being developed in order.
Security is another concern facing mobile VoIP as people facing concerns have been raised about how current encryptions are unable to secure communication over VoIP. Techniques offered with the current encryption standards blocks the possibility of two way authentication. This means that it is tot the responsibility of the end user to authenticate the network and this gives a hacker the ability to break and listen on conversations. Technology is becoming more and more vulnerable to attacks by malicious individuals and mobile VoIP is not different (Syed 45). Hackers have been known to bypass the set security parameters in order to gain access to sensitive information. One can only guess what could happen if terrorist gain access to sensitive military conversation, the results would be disastrous. Phone manufacturers are quickly coming to the realization that security is a major concern for Mobile VoIP issues.
Another challenge that is encountered by VoIP users is that the technology ceases to function when power is interrupted or is not serving the hardware that it depends on. Since VoIP is dependent on electricity, we have to consider of case where there is a power black out. This can only spell doom for subscribers in the midst of any call. This will affects a vast majority of subscribers as can lead to a communications breakdown within a region.
Solutions to Challenges
As much as there are challenges to the advent and spread of mobile VoIP, man has never shunned away but has always looked for how we can make life more comfortable. When discussing about mobile VoIP, researchers and scholars in conjunction with phone manufacturers have come up with ways in which to go around the challenges discussed above. A good example is how manufactures have agreed to come up with open protocols that will support all phones. This is together with an initiative to drive the popularity of mobile VoIP among service providers. Service providers are incorporating billing methods that can calculate how much to charge the customers ion mobile VoIP calls especially long distant and international calls.
Service providers are also in the process of streamlining quality of serve among subscribers. Latency within the current 3G frame work is being handled by enhancing subscriber capacity and also more codec are being in cooperated into the networks in order to boost sound quality. Security is being enhanced by changing the current authentication methods on the hardware being used by service providers this requires them to upgrade their hardware although it comes with added costs. Application developers such as Skype are on the forefront of offering mobile VoIP in partnership with service providers such as AT&T. (Syed 45).
Phone manufactures in conjunction with the service providers are developing new marketing plans tat will boost he spread of dual mode phones that can support mobile VoIP. Through lowering the costs of the purchasing the phones, they are trying to boost the uptake of technology by consumers. Subscribers need to experience faster speeds need lower cost of making calls within mobile VoIP in order to appreciate it more.
Conclusion
Mobile VoIP is the future of cellular technology as most traffic will be switched from circuit switched systems to packet switched systems. VoIP allows service providers to carry more traffic in their networks. This leads to better quality as congestion is eliminated. Subscribers also benefit from cheaper calls. This will not only lead to an increase in the revenues of the consumers but it also contributes to a better GDP as business can be freely transacted at any time. The rapid flow of information ensures that decisions can be made with the right information in place. The governments also stand to benefit as the tax imposed on such services further contribute to the coffers of the Government. Mobile VoIP has the ability to transform the lives of everyone and it is hence the duty of researchers and scholars in conjunction with the manufactures to come up with better ways in which access can be boosted for everyone.
Works Cited
Markova, Ekaterina. Liberalization and Regulation of the Telecommunications Sector in Transition Countries: The Case of Russia. London: Oxford Publishers, 2008. Print.
Radhaman, Gadhu. WiMAX: a wireless technology revolution. New York: CRC Press, 2007.Print.
Syed, Ahson. VoIP Handbook: Applications, Technologies, Reliability, and Security. New York: Press, 2008.Print.