My Conclusion about WCDMA technology

picture from: http://www.samsung.com/global/business/telecommunication/productType.do?ctgry_group=11&ctgry_type=17

In this blog, I first introduced evolution of mobile generation networks from 1G to 3G. Second, I analyzed the advantages and disadvantages of GSM, which is still dominant in the worldwide mobile market, and summarized that the migration path from 2.5G to 3G via GPRS and EDGE to UMTS is the path that the majority of mobile carriers worldwide intend to take. Because of various emerging technologies, like GPRS, EDGE, WCDMA, CDMA2000 and so on and other aspects such as potential of new markets, fixed-to-mobile substitution, I believe that the global mobile market will still grow in the future ten years. Hence, I pointed out that the evolution from GSM to 3G would bring more opportunities to this changing industry.

Then I focused on the WCDMA technology, the 3G successor to GSM. After listing the features of WCDMA technology, I made a comparison between WCDMA and its strong competitor CDMA2000 from both technical and economic aspects. Higher volumes permit more attractive prices for network infrastructure, system technology and for mobile end devices. This is already having an effect on the lower end of the market, where unsubsidized cdmaOne terminals cost almost twice as much as GSM/GPRS devices. The expenditure for research and development will also be proportional to the share of the global market, with a positive effect on the speed and time to market. The product portfolio makes this clear: Over 300 GSM handsets are on the market, approximately twice the number of cdmaOne models. Hence, the technologies derived from GSM enjoy the benefits that come from longer periods of development and maturation. The range of value-added services is both wider and more multi-faceted. The return on investment can be achieved faster. Roaming and service continuity also speak out in favor of migration to W-CDMA technology.

In addition, I also talked about HSDPA, the first evolution of WCDMA technology. There were almost 3 times the number of commercial HSDPA network launches compared to CDMA 1x EV-DO from mid-June to mid-September 2006.

At last, I analyzed the possible strategy for GSM operators by integrating GSM and WCDMA as a seamless network to meet the market with respect to the number of subscribers, the way they will use the services, the amount of money customers will spend on telecom services, the amount of money operators will save. All in all, this GSM/WCDMA integrated seamless network adds flexibility in the 3G deployments, enhances system performance, protects network investments through reuse of resources and supports the growth of today’s services as well as the creation and growth of mobile services beyond voice. So my conclusion is that WCDMA/HSDPA will be the leading 3G technology globally in the future.

One of big benefits of WCDMA technology：Great cost savings for GSM operators

Previously, I have mentioned that there are a lot of advantages and benefits of WCDMA technology over other technology in mobile market. This time we will closely look at one of these benefits: cost savings. When evolving from a pure GSM network to an integrated GSM/WCDMA one, two different areas are the sources of cost savings: capital expenditures and operating expenditures. Both will be analyzed below with regard to potential savings.

1. Capital expenditures saving areas
As we can see, the seamless network certainly protects an operator’s GSM investment by reusing GSM resources when evolving toward a 3G network. There are several areas in which operators can realize savings:
(1) The radio access network;
(2) The packet-switched core network;
(3) The circuit-switched core network;
(4) Charging and billing.

For example, the radio access network, one of the most expensive parts of a wireless network, offers several areas for potential savings when building the UTRAN, such as
• Sharing the UTRAN with other operators.
• Co-location and coexistence of GSM and WCDMA
• Using common operations and management subsystems for both GSM and WCDMA
• Having cabinet footprint and installation methods be the same in 2G and 3G.

Additional savings in the operations field are possible because all the established procedures for maintenance, technical support and spare parts management remain the same. What’s more, little to no additional training is required for the field support engineers.

2 operating expenditures saving areas
There are many benefits from operating the GSM and WCDMA networks as a single network, especially when it comes to saving operational costs. With two separate networks, the complexity of running the operator’s business increases exponentially. The operator can also realize significant savings by choosing fewer vendors to provide its network.

Here, we will analyze the major aspects of the single network and the vendor operator relationship with regard to potential savings and ease of operations. They are:
(1) Customer service management: is one of the biggest expenses of running a mobile operator business. Having a common customer care system, a single subscription and one billing system leads to substantial operating expenditures savings, both in terms of personal and training costs. The layered architecture of the seamless network makes it possible to realize these savings.

(2) Technical planning: For every network and vendor, the operator needs to establish an interface team in order to plan and to coordinate ongoing operations. This results in additional costs for highly skilled personnel on both the management and technical levels.

(3) Training: Maintaining two separate networks, each with its specific products, significantly increases the cost of training. Bringing in network equipment from a new vendor automatically leads to new training requirements for operating, maintaining and supporting the new products.

(4) Installation services: especially in the radio access network, comprise a major portion of operational costs. Efforts behind the initial deployment of all network elements are much higher when equipment from different vendors. This smooth evolutionary path enables predefined interconnection and facilitates upgrade procedures. This requires less material and offers smoother installation compared to overlaying equipment from other vendors. It also reduces the human effort and leads to cost reductions.

There are still a lot of other aspects, such as operations, maintenance and support, interoperability testing, processes and human interfaces. The strategy of a GSM/WCDMA seamless network adds flexibility in the 3G deployments, enhances system performance, and protects network investments through reuse of resources. This solution will help the operator secure the satisfaction and loyalty of its great amount of current GSM subscribers. I think every GSM operator will agree that this vital asset must be protected during this GSM to WCDMA transition period, because it is the foundation for future 3G businesses.

Rapid growth ahead for WCDMA/HSDPA mobile market in Europe

The European mobile broadband market is growing exponentially with demand fuelled by declining prices and improving performance. It is said that Vendors’ 2007 financial data indicated an increase in shipments in the range of 40–50 percent and a general price reduction of 20 percent. Until 2011, the mobile broadband market is expected to increase at a compound annual growth rate of 22.9 percent to reach € 3.0 billion. Device revenues are forecasted to increase at a faster rate than network revenues. While the expected high demand from the PC-industry will lead to higher shipment volumes, the vast majority of new subscribers will only be occasional users generating lower network ARPU.

WCDMA/HSDPA and legacy standards are expected to remain the dominant network access technology throughout the entire period with a market share well above 90 percent. We should notice that at the end of 2006, there were about 3.3 million active WCDMA/HSDPA mobile connections in Europe, compared to less than a quarter of a million for all other technologies combined. Although CDMA 450 has achieved some penetration in the Czech Republic, Romania and Scandinavia and will remain an alternative in areas without WCDMA/HSDPA coverage, deployments of WCDMA/HSDPA in lower frequency bands is likely to reduce the traction of EVDO on the European market in the longer term. WCDMA/HSDPA evolves rapidly as a technology, having advanced from peak data rates of 1.8 Mbps for commercial networks in early 2006 to 7.2 Mbps downlink and 2.0 Mbps uplink in the first half of 2007.

Here, I would like to mention that CDMA 450 is a commercially and technically viable technology in operation today providing cellular voice data and WLL services. CDMA450 is a TIA-EIA-IS-CDMA2000 (CDMA-MC) system deployed in 450 MHz which includes a family of standards developed by 3GPP2, published by TIA and approved by ITU for IMT-2000: CDMA2000 1X, CDMA2000 1xEV-DO and CDMA2000 1xEV-DV. Currently, CDMA2000 1X and CDMA2000 1xEV-DO are commercially available for the 450 MHz band and CDMA2000 1xEV-DV is being developed. In my opinion, CDMA 450 is a real competitor for WCDMA/HSDPA. However, the European investment community is ignoring the benefits of CDMA technologies in the 450 and 800MHz frequency bands.

Some people asked question that what are the real market prospects for alternative mobile broadband technologies like CDMA 450 and WiMAX? Frankly speaking, I do not believe that WiMAX will have any major impact on the European market in the coming five years. Any successful alternative network service provider must overcome a number of formidable barriers. These must include securing sufficient radio frequency spectrum, financing and constructing completely new infrastructure and finally gain a competitive edge against three to four established WCDMA/HSDPA network operators, who by that time will offer network speeds of at least 14.4 Mbps at price points comparable to DSL. The prospects for FLASH-OFDM and other 802.20 standard technologies also appear relatively less attractive.

All in all, I think the WCDMA/HSDPA technology would win the majority of mobile market in Europe in the future. Anyway, the popularity of mobile broadband is starting to have an impact on the overall strategies of network operators in many parts of Europe. Of course, we should be clear about which markets have the highest penetration rates and which are lagging behind? There are significant differences in pricing between operators, as well as markets. In addition, study shows that Greece, France and the UK have the highest overall price levels, while the lowest are found in Austria, Sweden, Hungary and Poland.

Evolution of WCDMA

As we can see, the introduction part of WCDMA follows a natural evolution of 2G networks. Then the term "WCDMA Evolved" describes the evolution of WCDMA addressing both operators' need for efficiency and end-user's demand for enhanced experience and simplicity. WCDMA is evolving to handle higher bit rates.

In the first step downlink was improved. WCDMA 3GPP Release 5 extends the specification with HSDPA, which is an enhancement of WCDMA. HSDPA improves the end-user experience by increasing peak data rates to 14 Mbps in the downlink, reducing delay; and providing 2-3 times more system capacity.

In the second step the uplink has been enhanced. Through these capabilities, operators benefit from a technology that provides performance for improved end-user experience for Web access, file download and streaming services. Wireless broadband access to the Internet, intranet and corporate LAN benefits greatly from 'WCDMA Evolved.'

The Concept：In WCDMA 3GPP release 5, WCDMA has been extended with a new transport channel, the high-speed downlink shared channel (HS-DSCH), which provides enhanced support for interactive, background, and to some extent, streaming radio access bearer (RAB) services in the downlink. HS-DSCH transmission facilitates several new features. But to support them with minimum impact on the existing radio interface protocol architecture, a new MAC sub-layer, MAC-hs, has been introduced for HS-DSCH transmission. MAC-hs makes it possible to retain a functional split between layers and nodes from WCDMA 3GPP release 99. A minimum of architectural changes allows a smooth upgrade to HSDPA and ensures HSDPA operation in environments where not all cells have HSDPA functionality.

The Benefits：The primary benefit of HSDPA is the improved end-user experience. In practice, this means shorter download times through higher bit rates (14 Mbps peak rate) and reduced roundtrip time over the air interface. HSDPA also provides advantages for operators by introducing greater system capacity.

Improved end-user experience: HSDPA can reduce the time it takes to download large files by a factor of 20. HDSPA opens up for enhanced end-user experience when using WCDMA for wireless broadband applications such as intranet and Internet access via laptop computers. Here the reduced delay improves the traditional web access. Download of emails and other heavy files are improved by the increased peak data rates.
Improved system capacity: A further benefit of HSDPA is greater system capacity. HSDPA increases capacity in several ways:
1.Shared-channel transmission results in efficient use of available code and power resources in WCDMA
2.The use of a shorter TTI reduces roundtrip time and improves the tracking of fast channel variations
3. Link adaptation maximizes channel usage and enables the base station to operate close to maximum cell power
4.Fast scheduling prioritizes users with the most favorable channel conditions
5.Fast retransmission and soft-combining further increases capacity
6.16QAM yields higher bit rates
Depending on the deployment scenario, the combined gain in capacity is from two to three times that of WCDMA 3GPP release 99. Another benefit of HSDPA is that it is an integral part of WCDMA. Wide-area mobile coverage can be provided with HSDPA. At present, WCDMA can provide simultaneous voice and data services (multi-services) to users on the same carrier. This also applies to HSDPA, which means that spectrum can be used efficiently. HSDPA also makes efficient use of power by employing unused power.

Wide Coverage：WCDMA will be evolved to handle higher bit rates. The first step is to improve the downlink in WCDMA. HSDPA will greatly improve the end-user experience by increasing bit rates to as much as 14 Mbps in the downlink and reducing delay. In addition, no new spectrum / carrier is needed to roll out HSDPA in the network. At present, WCDMA can provide voice and data services on the same carrier simultaneously. This also applies to HSDPA.

Hence, with the advantages of HSDPA, 'WCDMA Evolved' will further enable operators to provide end-users with more advanced wireless broadband applications offering wide area coverage and mobility.

Comparison between WCDMA and CDMA2000 from Market share and economic aspects

The results of comparing the two systems are much clearer when economic aspects are taken into our account. For example, market share, economies of scale in the production of network equipment and end devices as well as the possibilities for international deployment，such as roaming. In this sector, GSM and its successor technologies GPRS, EDGE and UMTS/W-CDMA are dominant.

Data shows that Over 750 million subscribers, at August 2002, in over 175 countries clearly make GSM the leading mobile communication standard worldwide. In 2001, 81 percent of all new subscriptions were for GSM devices, whereas only 13 percent were for cdmaOne devices (EMC Database). The current subscription trend suggests that the gap between market shares for GSM and CDMA will continue to widen.

cdmaOne installations only really played a role in the Americas, particularly in the USA, and to a certain extent in the Asia Pacific Region, in particular in Korea. South Korea provided 70 percent of the cdmaOne customer base in the Asia Pacific Region. In June 2001 this was approximately 28.1 million cdmaOne subscribers which is roughly a third of the entire cdmaOne customer base worldwide. But this customer base is beginning to crumble as the carriers SKT and KT opted for W-CDMA as their 3G path. These two carriers together control 85 percent of the market in Korea.

Let’s look at Japan, NTT DoCoMo and J-Phone (with a combined share of the market amounting to 75.7 percent of all Japanese subscribers) opted for UMTS/W-CDMA as their 3G technology. Based on these facts and analysis, I have to say that WCDMA has the edge over the seriously competitive cdma2000 versions.

Comparison between WCDMA and CDMA2000 from technical aspect

W-CDMA
First let’s look at WCDMA technology. In conjunction with GPRS and EDGE which are evolutionary developments of the GSM technology, W-CDMA can be applied, both cost-effectively and with little need for additional resources. Mobile telephones and other devices used in W-CDMA mode will be able to use GSM, GPRS or EDGE, which ensures a seamless transition within the existing networks. W-CDMA attains its high performance by transmitting signals from the various services which require variable data rates by assigning bandwidth flexibly (bandwidth on demand). Each signal is coded, and then modulated and distributed ("spread") across a 5 MHz transmission bandwidth. The frequency band is available to all subscribers simultaneously. The coding identifies the signals destined for the each individual subscriber. All other users that do not have the appropriate codes will only receive the sum total of all signals in the form of undefined noise.

cdma2000
cdma2000 is a family of mobile technologies that are based on a narrow band (1.25 MHz channel bandwidth) version of CDMA and are derived from the Interim Standard No. 95 (IS-95) which was published in 1993 by the North American trading organization, the TIA. Although a multi-carrier CDMA that is able to handle multiple sequences IS-95 carriers was originally suggested within the framework of IMT-2000, only the single carrier solution of the cdma2000 family has remained (hence the name 1x). The first step takes the form of 1xRTT (also called cdma2000 1x) a slightly improved variant of IS-95 including the integration of a packet-switching core network which delivers similar performance to GPRS. Since the data throughput did not meet the 3G guidelines, the HDR (High Data Rate) system proposed by Qualcomm in 1998 was introduced as an evolution phase and was accepted as a standard known as cdma2000 1xEV-DO in August 2001. 1xEV-DO is designed especially for data services that are not runtime critical, and requires a separate frequency band. This means that transmission capacities are reserved exclusively for data, even if there is no need, which can be a waste of radio resources. In order to eliminate this problem, the new version, cdma2000 1xEV-DV, is designed to handle both voice traffic and data on a single frequency bandwidth. Only this second stage of evolution can be compared to W-CDMA.

Hence, the wider bandwidth of W-CDMA promises to deliver particularly good service quality and proliferation characteristics. The technology of 1xEV systems from cdma2000 appear to be stretched to its limits in terms of additional capacity increases. In contrast, W-CDMA still has potential for increased performance as is made clear by the HSDPA upgrade standard approved in Spring 2002. This allows for a downlink data rate of up to 10 Mbps thanks to improved transmission mechanisms optimized for data transfer.

Although the migration path from GSM to UMTS/W-CDMA also brings about a change in the technology used for transmission, solutions for the reuse of existing network infrastructures appear to be simpler and more cost-effective for this technology than for the cdma2000 system family. Thus, for instance, upgrading to version 1xEV-DO would require huge investment to set up a separate overlay network.

We should notice another problematic issue is the GPS satellite detection of the base stations which is required for cdma2000. Since GPS technology requires an uninterrupted line of sight to the satellites, small cells, for example, inside buildings, or between tall buildings, require additional outlay for installing external GPS receivers. W-CDMA on the other hand operates in asynchronous mode and, as a result, can be used universally without GPS detection.

From the above analysis, we can draw the conclusion that WCDMA outweighs CDMA2000 from a technical aspect.

Standardization activities on WCDMA

In early 1998, to expedite the process of IMT2000/3G standardization and the global acceptance of proposed radio transmission technologies, a concept of a “Partnership Project” was proposed by the European elecommunications Standards Institute (ETSI). This proposal initiated two Third-Generation Partnership Projects (3GPP and 3GPP2) with two different, but related areas of focus.

Each of the 3GPP and 3GPP2 projects involves a number of regional standardization bodies as organizational partners. For 3GPP the original scope was to produce globally applicable and acceptable technical specifications for a Third-Generation Mobile System based on the evolved GSM networks. This scope was subsequently amended to include the maintenance and development of Technical Specifications for GSM and its evolution to General Packet Radio Service (GPRS) and Enhanced Data rates for GSM Evolution (EDGE).

Similarly, the scope of the 3GPP2 work was to harmonize different variations of cdma2000 in a single family of standards. This scope was also expanded to include the development of a data-optimized air interface called the high-rate packet data (HRPD) system. In the development of cdma2000 systems the core network specifications are based on an evolved ANSI-41 and IP network; however, the specifications also include the necessary capabilities for operation with an evolved GSM-MAP-based core network.

As a result of harmonization efforts in 3GPP and 3GPP2, the following three major technologies have been identified and included in the IMT2000 family of standards: The Direct-Sequence mode is based on WCDMA specified by
3GPP (UTRA/FDD), the Multi-Carrier mode is based on cdma2000 Multi-Carrier specified by 3GPP2, and the TDD mode is based on the TDD mode specified by 3GPP (UTRA TDD).

Wideband CDMA (WCDMA) has been chosen as basic radio-access technology for UMTS/IMT-2000 in all major areas of the world. Most GSM operators are planning or have begun deploying IMT2000/UMTS based networks using WCDMA technology. Many IS136/TDMA-based networks have also joined the GSM group and have decided to migrate to WCDMA.