A Q&A with Seho Park, manager, network strategy team at South Korean mobile operator, SK Telecom

 

Q: What is the main issue regarding moving to new wireless technologies such as LTE/LTE Advanced and WiMAX?

SP: Regarding evolution to a next-generation network, we, as an operator, have to consider locating new equipment with existing infrastructure to enhance efficiencies and data throughput. Thus we need to develop engineering technology in areas such as architecture distribution and relay station applications to minimize coverage holes while pursuing such co-existence.

Q: How can orthogonal frequency-division multiple access (OFDMA) and multiple-input, multiple-output (MIMO) antenna technology be further improved before the air interface technology reaches Shannon’s limit in terms of bits-per-second-per-Hertz?

SP: In terms of OFDMA and MIMO, many technologies have been developed to reach Shannon’s limit. However not all of them have been chosen as standards to be applied to actual systems. Further theoretical studies are expected while a great amount of effort is being made to make already-developed technologies applicable to systems.

Q: Are other techniques being considered to improve air interface performance or is OFDM it?

SP: OFDM is not the ultimate air interface technology but for the time being cellular systems will be developed based on the combination of OFDM and MIMO. New technologies will emerge as the result of research on performance enhancement of the air interface. In a broader sense, improvement of network performance will rely more on other technologies such as:

• Innovation in topology: collaborative MIMO and self-optimising networks
• Relaying
• Adaptive networks – combining different networks within cells like GSM/W-CDMA/LTE, Wi-Fi and femtocells

Q. Can you explain which techniques SK Telecom thinks are important and why?

SP: Voice service can be realised via macro-type base stations but as the network targets high-speed data services, various small type devices are expected to co-exist heterogeneously. Therefore with next-generation network where diverse configurations and standards co-exist, self optimisation and healing network technologies that operate automatically in an adaptive manner will become very important.

In addition backhaul capacity of base stations needs to be increased to meet high-speed data demand. To save on the operational expenses that will need to be incurred during this process, wireless backhaul and relaying technologies will be used.

Q: What are the key challenges in implementing these techniques?

SP: If most operators demand the same requirements, mass production of standardised equipment will be possible, thereby allowing operators to adopt equipment at low cost. However, since each operator is expected to have its own interests stemming from differences in network portfolio and the environment (i.e. whether it has a fixed-line network), creating a common profile that satisfies the majority of operators is a key issue in realising such systems.

Q: Where is SK Telecom up to with regard deploying HSPA, and announcements/trials on LTE?

SP: SK Telecom is already providing commercial HSPA services including HSDPA nationwide and HSUPA. However, we have not decided whether we will provide LTE first or directly evolve to LTE Advanced.

Q: The discussion so far is about new technologies and wireless roadmaps. Can SK Telecom discuss the importance of these developments versus the practical issues it must address near term? For example, there may be much you can do with existing technologies before you need LTE.

SP: The most important issue for SK Telecom is to secure frequency bandwidth capacity needed for voice services. We are currently providing the service based on four HSPA carriers but due to rapidly increasing voice traffic, they will soon become overloaded. Thus the most urgent issue is to secure more network capacity by receiving additional carriers. Moreover, to lead in the highly competitive Korean market, we must complement coverage by building networks in non-service areas and strengthen quality of service to maintain a competitive edge by investing in infrastructure such as in-building coverage etc.

Q: So just how urgent is the need for LTE/LTE Advanced and WiMAX?

SP: Of course developing a next-generation network is an important task for us. LTE Advanced and WiMAX Evolution (IEEE 802.16m) are emerging as candidates for 4G. Technology standardisation is expected in 2011, followed by commercialization after 2013. At present, SK Telecom is open to both LTE and WiMAX. Moreover, data business models need to be specified before adopting LTE.

Developing 4G network is our long-term task. For the short–term, we place great importance on securing new growth by focusing on our role as an Industry Productivity Enhancer (IPE) and creating viable business models in the business-to-business (B2B) market as well as addressing policy issues, such as Green IT, and developing solutions that meet industrial needs.