Telecom Technology Convergence

January 20, 2014

Yahav Biran

University of Phoenix









Technologies are emerging and dying frequently; very few technologies are completely disrupting the business and introducing a complete new landscape e.g. invention of electricity and motor vehicle. Most of the emerging technologies requires convergence with other existing platforms to get a full influence. Some of the ways to ensure technology convergence starts in early stages of the technology strategy design. Methodical technological projecting is vital component in integrating technology with other technologies, such as, the technology life cycle (S-curves) (Twiss, 1989). Telecommunication technologies are following the same patterns. Chromatis solution was about to disrupt the Dense Wavelength Division Multiplexing (DWDM) technology and could influence the fiber optics market. However, the disruption never happened because of the early 2000s recession. In contrast, IP Multimedia Subsystem (IMS) is a bleeding technology for almost ten years. IMS is about to converge with the emergence of the Voice over LTE (VoLTE) technology. VoLTE expected to be one of the main voice service differentiator provided by telecommunication operators that compete with the free VoIP technology offered by the over the top service providers (OTT).  

Keywords: Chromatis, IMS, VoLTE, leading edge, bleeding-edge technology


Telecom Technology Convergence

Technology life cycle is defined above the value proposition and the technology cost of research and development. In the first phase, technology considered as bleeding because its potential has not yet demonstrated, and the cash flow is negative. In later phases, when the technology is demonstrating some profitability, it is crossing the bleeding edge and becoming a leading edge technology. Not all technologies are able to become a leading technology from several reasons. Moreover, when technology reach the maturity edge and start leading, it converges with other technologies. In some cases, the only way for technology to succeed is to converge with other technologies.

This paper will review few examples of leading and bleeding technologies from the telecommunication industry. Chromatis solution was about to disrupt the Dense Wavelength Division Multiplexing (DWDM) technology and could influence the fiber optics market. However, the disruption never happened because of the early 2000s recession. In contrast, IP Multimedia Subsystem (IMS) is bleeding technology for almost ten years, and about to lead with the emergence of the Voice over LTE (VoLTE) technology that telecommunication operators are interested in differentiating themselves from the over the top (OTT) players.

Bleeding Edge Technologies

IP Multimedia Subsystems (IMS)

Background. IMS is a wireless standard for architecting IP multimedia services designed by the 3rd Generation Partnership Project (3GPP). The standard consists of radio, core network and service architecture. The standard composed by both telecommunication manufacturer and operators. Its main purpose is to establish one standard that will help to build one cohesive and interoperable network from both carriers and manufacture sides, in particular when addressing the technological challenges of the 3rd generation cellular network (3GPP, 2006).

When the IMS standard was conceived, the common assumption was that the network and its value added services (VAS) are ruled by the carriers and the telecommunication manufacturer. Back in late 1990s and early 2000s, telecommunication manufacturer such as Nokia, Ericson, Motorola, and Alcatel use to build both the cellular antennas and the user equipment (UE) aka the mobile device. The 3GPP committee tried to define how different mobile service will integrate with the network. It will also create a new portfolio that can be monetized for both the carriers and the telecom manufacturer.

Architecture. In a nutshell, any system that complies the IMS standard fulfills four main components: Home Subscriber Server (HSS), Serving Call State Control Function (S-CSCF), Proxy Call State Control Function (P-CSCF), and Interrogating Call State Control Function (I-CSCF).

HSS. Home subscriber server is the central subscriber repository used within IP multimedia subsystem. The IMS HSS provides details of the subscribers to the other entities within the IMS network, enabling users to be granted access or not dependent upon their status (3GPP, 2006).

S-CSCF. The Serving Call State Control Function is one of the major entities within the overall IMS architecture. It is at the core of many functions within an IMS network, communicating with many other functions within the overall system (3GPP, 2006).

P-CSCF. Serve as the main network proxy. In this respect, all inbound and outbound session initiation protocol calls runs via the P-CSCF whether in the home or a visited network (3GPP, 2006).

I-CSCF. The Interrogating Call State Control Function is one of the main elements within the overall IP multimedia subsystem architecture. Its main purpose is to forward session initial protocol requests to the appropriate S-CSCF (3GPP, 2006).

Based on the IMS standard telecom manufacturer invested research and development while no operator adapted the technology even after the transformation into 3G network technologies as initially planned.

Market Landscape. Later on with the rise of the smartphone by RIM, Apple and Google, the telecom landscape became more heterogeneous. New services emerged under the nose of the former leaders, the carriers and the telecom manufacturer. Based on this trend, the telecom carriers hesitated to adapt the new technology even when the cellular networks upgraded to 4G and LTE technologies. Hence the IMS was bleeding for almost ten years since adapted by the 3GPP.  

Dense Wavelength Division Multiplexing (DWDM)

Background. Chromatis networks enabled carriers connecting their data centers with the T1 backbones network. The technology is based on Dense Wavelength Division Multiplexing passed over a fiber optic. The main value proposition was more efficient usage of the existing fiber and cost effective connection between the local carriers and the T1 metropolitan network.

Technical Aspects. Chromatis product separates the optic wave into various wavelengths that travel on a single thread of fiber (Figure 2). The product enables numerous connections onto a single fiber hence, reducing communications cost per bandwidth. Moreover, the multiplexing method allows a continuous signal meter for bandwidth adjusting, which significantly improve the bandwidth monetization capabilities.

The solution supports Synchronous Optical Networking (SONET) standard; therefore, it allows metro networks connect to long-haul services and provides interconnection handoffs of SONET based networks. Figure 2 depicts how the new switch multiplexes the signal in both sides of the fiber and able to pass four times more than a regular switch.


Market Landscape. According to FCC (2014), The FCC forced AT&T to give up its 22 local Bell companies. Because of this decision, a new market has evolved, local Telco carriers that include: Bell Atlantic, Nynex, Qwest, WS West, Southwestern Bell, and Pacific Telesys. Lucent Technologies decided to invest in the progressed new market and acquired Chromatis Networks for $4.5 billion on 2001. Although the bleeding edge was over at that point, it last only six months. On Aug 2001, Lucent decided to close the product line as it addressed regional and small carriers. The vast majority of the potential customers of Chromatis product, the local carriers, have shrunken under massive debt and declared bankruptcy or ceased operations because of early 2000s economic recession (Henderson, 2004).

“We have come to the conclusion that, in the current market conditions, we will have a renewed focus on the world’s largest [telecom] service providers. . . so we decided to streamline our optical portfolio, … Lucent will concentrate on sales to telecom giants, such as AT&T Corp., Verizon Communications, Deutsche Telekom and Vodafone Group.” (Rendleman, 2000, para. 1)


Leading Edge Technologies

Voice over LTE

Background. Long Term Evolution based networks are adapted as one of the common high speed cellular network technology by many T1 carriers around the world. Currently, LTE based networks serve data traffic only. Voice and messaging traffic are served by the legacy GSM and EDGE networks. Telecom operators are seeking to utilize their LTE networks for voice use case and decommission the 2G and 3G networks. Moreover, using LTE network technologies for delivering voice and messaging services can help the telecom carriers to differentiate themselves from the rest VoIP services. The technology that allows voice over the long-term evolution network calls VoLTE.  

However, transfer voice over LTE requires a redesign of quality assurance standards of the transmitted voice. Also known as Quality of Service criteria’s (QoS). The criteria will ensure that VoLTE provides the same or even better voice quality than the legacy EDGE/GSM network technologies.

Technical Aspects. As far as Open Systems Interconnection (OSI) layers is concern, 2G and 3G voice calls are terminated within the first three layers also known as 2G/3G dedicated voice bearers e.g. physical (WCDMA, OFDM), data link (PDCP, RLC) and Network (IP, RPC, ATM).

The 4G dedicated data bearers require extra handling of the entire seven layers stack in order to initiate and maintain voice calls.

Unlike 2G/3G networks, just because a reliable connection on the first three layers exists, does not guarantee the call quality. It takes the entire protocol stack to handle the voice session. E.g. layer five, the session layer where the IMS components are handling requires a new QoS metrics in every step of the voice call, initiate, talk and terminate.


In order to ensure the required QoS when delivering voice over LTE, a dedicated bearer between the voice and the data spectrum is required. Moreover, there must be an indicator that identifies the upper bound of acceptable packet errors or delays. This indicator will help the underline network service to refine its resource allocation (Whytock, 2012). The IMS S-CSCF component has the ability to handle this task as it maintains the call state control function.

Market Landscape. As of the first quarter of 2013, there are 6.4 billion mobile subscribers, with smartphones comprising 50% of new mobile devices sales.

Voice and SMS represent 70% of all global wireless revenues. Assuming VoLTE is adapted by the carriers subscribers, the revenues estimated to reach $2 billion by 2016.

According to Chaten(2012), the revenues of the carriers are declining. The carriers can either become a VAS (value added service) like the OTT players, Skype, Google, Amazon, and Apple. Another strategy will be sticking to its core business, being a pipe builders of data, voice and messaging.

Wireless is highly revenue market, many operators and network infrastructure, competing to get a share of this market average revenue per user is no longer increasing, the opposite, according to recent reports, revenue per user decreased over the last two quarters of 2013. The operator must find ways to differentiate their service, in order to increase its revenue.   Reduce the cost of what it takes to serve a customer so they can offset the declining average revenue per user.

HD voice is one of the ways to seek competitive advantage. According to LG Uplus (2012) 73 network operators around the world, seek to introduce HD voice services through their network. VoLTE and other services moving to more efficient all IP LTE networks. This is the way network operators will reduce costs and serve user more efficiently. The way VoLTE voice experience offered by different suppliers can be compared is a current marketing challenge.

Transformation Through Convergence

The answer to the question whether bleeding technology can lead through convergence is not definitive. As we saw in the IMS and VoLTE case, turning into a leading technology through convergence, requires not only technological intersection. Marketing strategy intersection is a vital component in this success. The QoS requirements of VoLTE bubbled up the necessity of the IMS capabilities for insuring such standards. Moreover, both the telecom operators and the manufacturer strategy intersect when they try challenging the OTT business model in general and the VoIP scenarios in particular.

The Chromatis example shows how technology convergence can fail where the telecom landscape was not ready or affected by the global economy. The 2000 recession affected the success of the regional carriers. While some of the carriers merged back with the big carriers, Chromatis product did not fit to the T1 carriers requirements, hence Lucent decided to focus on T1 strategy.  


Relationship among different technologies can yield exciting consequences. According to Borgianni and Federico (2012), the vast majority of new technologies are doomed to fail. Those who will survive converge with existing technologies unless it is a major disruptive technology. The telecom industry examples depict the complexity involved in anticipating whether technology will become leading edge technology, how and with what legacy technology it will converge. It is clear that science is not the only component, in some of the cases it is a minor factor (Chromatis case, 2000).
Moreover, the IMS example shows that, after ten years of bleeding, another emerging technology can evolve and shift the trajectory of the bleeding technology into an innovative technology.



  1. Twiss, Managing Technological Innovation (London: Longman, 1989)

Borgianni, Yuri; Rotini, Federico. International Journal of Innovation Science. Dec2012, Vol. 4 Issue 4, p259-268. 10p. 2 Graphs.

Technical Specification Group Services and System Aspects (2006), IP Multimedia Subsystem (IMS), Stage 2, TS 23.228, 3rd Generation Partnership Project

FCC, 2014; American Tel. & Tel. Co. v. FCC, 298 U.S.App.D.C. 1, 974 F.2d 1351 (1992); Retrieved from

John S. Mazur, Peter Kjeldsen; Lucent’s Jettisoning of Chromatis Wise but Costly; 04 September 2004; Gartner research; Retrieved from

Rendleman, John. Lucent Shuts Down Chromatis Networks eWeek. 06/05/2000, Vol. 17 Issue 23, p30. 2/5p.

LG Uplus Corp.; LG Uplus introduces VoLTE with Ericsson.; Global Telecoms Business. Sep2012, Issue 139, p1-1. 1p.

Whytock, Paul (2012); When Will 4G Make The Great VoLTE Leap Forward?; Microwaves & RF. Sep2012, Vol. 51 Issue 9, p36-36. 1p. 1 Color Photograph.





Appendix A: Abbreviation




Dense Wavelength Division Multiplexing


Synchronous Optical Networking


Metropolitan Area Network


Wide Area Network


Long Term Evolution


Voice over LTE


IP Multimedia Subsystem


Federal Communications Commission


Over The Top


3rd Generation Partnership Project


User Equipment


Async Transport Mode


Voice over IP


3rd Generation Partnership Project


Home Subscriber Server


Serving Call State Control Function


Proxy Call State Control Function


Interrogating Call State Control Function


Quality of Service


Open Systems Interconnection


Session Initiation Protocol


Value Added Services