Standardization Activities for Next- Generation Mobile Communications Systems

 Akishige Noda

The 3rd Generation Partnership Project (3GPP) founded in 1998 by standardization organizations in Japan, Europe, North America, China, and South Korea released a set of specifications called Release 8 in December 2008. This release formally specified Long Term Evolution (LTE) technology and presented the evolved packet system (EPS), a new architecture covering the radio access and core networks. By supporting only packet communications and achieving more flexible frequency spectrum usage, LTE enables mobile communications at even higher bit rates and wider bandwidths. The explosive increase in new terminals like smartphones, however, is dramatically increasing the amount of data that the network must handle, making it necessary to further expand system capacity. To address these new issues, standardization activities for the Heterogeneous Network (HetNet) system and other new systems have begun, centered on 3GPP. This article describes standardization trends for next-generation mobile communications systems and Fujitsu’s contributions to standardization activities.

1. Introduction Division Multiple Access (W-CDMA), High-Speed The development of the third-generation Packet Access (HSPA), Long Term Evolution mobile communications systems is well (LTE)/system architecture evolution (SAE), etc. underway. It follows first-generation systems This article describes standardization based on analog technology and second- activities centered on 3GPP for third-generation generation systems based on digital technology mobile communications systems. and will provide higher transmission speeds to users worldwide. This development effort began 2. 3GPP when standardization organizations in Japan, The 3GPP was launched in 1998 by the Europe, North America, China, and South Korea Telecommunication Technology Committee launched the 3rd Generation Partnership Project (TTC) and Association of Radio Industries and (3GPP) with the aim of developing a third- Businesses (ARIB) in Japan, the European generation mobile communications system called Telecommunications Standards Institute International Mobile Telecommunications (IMT)- (ETSI) in Europe, the T1 Committee (now the 2000, a standard system that could be used by Alliance for Telecommunications Industry mobile communications operators and vendors Solutions [ATIS]) in North America, and the around the world. Fujitsu has participated in Telecommunications Technology Association 3GPP activities from the beginning and has (TTA) in South Korea to study and develop actively contributed to the standardization standard specifications for a third-generation of communications specifications for third- system having a core network based on generation radio access systems: Wideband Code Universal Mobile Telecommunication System

FUJITSU Sci. Tech. J., Vol. 48, No. 1, pp. 95–102 (January 2012) 95 A. Noda: Standardization Activities for Next-Generation Mobile Communications Systems

Terrestrial Radio Access (UTRA) and Global standards in various countries and regions by the System for Mobile Communications (GSM). The six regional standardization organizations known China Wireless Telecommunication Standards as “organizational partners.” Furthermore, to Group (CWTS) (now the China Communications make these specifications into an international Standards Association [CCSA]) was later added standard, the organizational partners as an organizational partner, giving 3GPP collaborate to propose 3GPP specifications to the its current form (Figure 1). Although 3GPP International Telecommunication Union (ITU) so initially targeted a third-generation mobile that they can be issued as ITU recommendations. communications system centered on a core network based on W-CDMA and GSM for study 3. 3GPP organization and development work, it later added Enhanced The 3GPP is broadly divided into four Data GSM Environment (EDGE) as a high-speed technical specification groups (TSGs): TSG-GSM/ data communications technology based on GSM EDGE Radio Access Network (GERAN), TSG- as a target specification standard. It also took Radio Access Network (RAN), TSG-Services and on the work of developing standard specifications Systems Aspects (SA), and TSG-Core Network for LTE and evolved packet system (EPS) and Terminals (CT). Each TSG oversees a technologies, which were released in 2008 as a number of working groups (WGs), where most of set of specification documents called Release 8. the work of studying and developing specifications The work of 3GPP is focused on the study is performed. The 3GPP organization chart is of standard specifications and the drafting of shown in Figure 2. specification documents for use with third- generation mobile communications systems. 4. Standardization trends Specifications prepared by 3GPP are released as The goal has always been to increase

Submit ITU (International Telecommunication Union) recommendations Migrate specifications to regional standards

Develop technical specifications 3GPP

Propose technologies

Individual Members

Provide funding and Provide specification documents on managerial support developed technologies

ARIB ATIS CCSA ETSI TTA TTC

Regional Standardization Organizations (Organizational Partners)

ARIB: Association of Radio Industries and Businesses ETSI: European Telecommunications Standards Institute ATIS: Alliance for Telecommunications Industry Solutions TTA: Telecommunications Technology Association of Korea CCSA: China Communications Standards Association TTC: Telecommunication Technology Committee

Figure 1 Relationships between standardization organizations.

96 FUJITSU Sci. Tech. J., Vol. 48, No. 1 (January 2012) A. Noda: Standardization Activities for Next-Generation Mobile Communications Systems

3GPP Project Coordination Group (PCG) Chairman: WEIGEL, Walter (ETSI) Vice-Chairman: SHIGETA, Noriyuki (TTC) Vice-Chairman: CHATTERJEE, Asok (ATSI) CHIN, Byoung-Moon (TTA)

TSG-GERAN TSG-RAN TSG-SA TSG-CT GSM/EDGE Radio Access Network Services Core Network and Radio Access Network and Systems Aspects Terminals

GERAN WG1 (Radio aspects) RAN WG1 (Radio layer 1 spec) SA WG1 (Services) CT WG1 (MM/CC/SM [lu])

GERAN WG2 (Protocol aspects) RAN WG2 (Radio layer 2 spec) SA WG2 (Architecture) CT WG3 (Interworking with external networks)

GERAN WG3 (Terminal testing) RAN WG3 (lub spec, lur spec, lu spec SA WG3 (Security) CT WG4 (MAP/GTP/BCH/SS) UTRAN O&M Requirements)

RAN WG4 (Radio performance CT WG6 (Smart card application SA WG4 (Codec) protocol aspects) aspects)

RAN WG5 (Mobile terminal) SA WG5 (Telecom management)

Figure 2 3GPP organization chart. throughput and broaden the bandwidth of mobile generation (W-CDMA) technology and by only communications systems. Throughput jumped about two times with the switchover from dramatically over a ten-year period, from about third-generation technology to enhanced HSPA 20 kb/s for the second-generation systems to (HSPA+), reflecting a decrease in the spectral- about 300 Mb/s with the introduction of the LTE efficiency improvement factor. There was only third-generation system in 2008. It rose again slight improvement with the switchover to LTE. to a maximum of 1 Gb/s with the introduction In short, achieving dramatic improvements of the LTE-Advanced fourth-generation in is becoming increasingly system in 2011. The evolution of radio access difficult despite the continuing trend toward technologies and increase in throughput from higher data rates and bandwidths. the second-generation system (GSM) to the LTE- For this reason, 3GPP is studying a Advanced fourth-generation system is shown in heterogeneous network called HetNet. This Figure 3. Third- and fourth-generation radio network consists of a hierarchical arrangement of access systems are compared in Table 1. cells of various sizes including macro, micro, pico, As shown in Figure 4, spectral efficiency and femto. The aim is to increase the capacity improved by about ten times with the switchover of the entire system. A conceptual diagram of from first-generation (analog) to second- HetNet is shown in Figure 5. generation (digital) technology. It improved Implementing HetNet will require by only about four times with the switchover enhancements in mobility control including from second-generation technology to third- cell-selection, interference-control, and

FUJITSU Sci. Tech. J., Vol. 48, No. 1 (January 2012) 97 A. Noda: Standardization Activities for Next-Generation Mobile Communications Systems

GSM EDGE W-CDMA HSPA LTE LTE-Advanced

1 G*3 1 G Non-3GPP RATs 300 M 200 M*4 80 M*1 100 M

14.4 M 42 M*2 10 M

2 M

1 M

Throughput (b/s) 384 k

100 k *1: 64QAM + 2 × 2 MIMO + Multi carrier 22.8 k *2: 64QAM + 2 × 2 MIMO *3: 100 MHz ch 10 k *4: 20 MHz ch

1998 2001 2003 2009 2012

Figure 3 Evolution of radio access technologies (RATs) and throughput.

Table 1 Comparison of radio access systems. W-CDMA () HSDPA/HSUPA (3.) 3G LTE (3.9G) LTE-Advanced () DL: CDMA DL: CDMA DL: OFDMA DL: OFDM (?) Access system UL: CDMA UL: CDMA UL: SC-FDMA UL: (?) Bandwidth 5 MHz 5 MHz 20 MHz Up to 100 MHz QPSK, 16QAM, 64QAM, QPSK, 16QAM, 64QAM, Modulation system HPSK, QPSK HPSK, QPSK, 16QAM etc. etc. DL: 384 kb/s DL: 14.4 Mb/s DL: 300 Mb/s DL: 1 Gb/s Max. data rate UL: 64 kb/s UL: 5.7 Mb/s UL: 75 Mb/s UL: 75 Mb/s Adaptable to circuit Dramatically improved Further improved data Feature Higher packet data speed switching services data rate and rate and mobility

DL: Downlink (base station to ) HPSK: Hybrid phase shift keying UL: Uplink (mobile phone to base station) QPSK: Quadrature phase shift keying QAM: Quadrature amplitude modulation CDMA: Code division multiple access HSDPA: High-Speed Downlink Packet Access OFDM: Orthogonal frequency division multiplex HSUPA: High-Speed Uplink Packet Access

functions as well as the development Similar to specifications developed to of new specifications. These enhancements improve throughput, data offload is being and developments are considered major proposed as a new direction in the development standardization issues to be addressed in Release of standard specifications. To give some 11 (functional freeze is scheduled for September background, these last few years have seen the 2012). loads on mobile communications systems jump

98 FUJITSU Sci. Tech. J., Vol. 48, No. 1 (January 2012) A. Noda: Standardization Activities for Next-Generation Mobile Communications Systems

10x

2G (GSM) vs (analog) 8x

6x HSPA+ vs 3G

4x

LTE vs HSPA+ 2x 3G (W-CDMA) vs

1994 97 00 03 06 09 12

Figure 4 Improvements in spectral effi ciency.

Fixed network – mobile interworking

Mobile core network Fixed network

Mobile backhaul Internet

Fixed access line (FTTx)

DAS Femto

Relay backhaul Pico

Micro Femto Femto Micro

Pico Relay Macro

DAS: Distributed antenna system Pico Cell Base Station Relay Base Station Femto access point (Base station) FTTx: Fiber to the x

Figure 5 Heterogeneous network with hierarchical arrangement of macro, micro, pico, and femto cells and relay base stations.

as a result of increased data communications smartphone usage. Additionally, new traffi c in driven by the introduction of fi xed-rate data- the form of machine-to-machine communications communication plans and the increase in and new services for synchronizing the

FUJITSU Sci. Tech. J., Vol. 48, No. 1 (January 2012) 99 A. Noda: Standardization Activities for Next-Generation Mobile Communications Systems

information of multiple subscribers who wish for the development of standard specifications to share calendar data, telephone numbers, that can be used with ease by all the major etc. is expected to impose an even bigger data- players in the LTE market, which means not communication load on mobile networks in the only base-station and network vendors but also years to come. To deal effectively with such terminal-chipset vendors, service providers, and forms of large-capacity data communications, content providers to name a few. Of particular 3GPP is moving ahead with the development of importance is the business and general consumer standard specifications on traffic offloading. market, which is represented as an ecosystem The 3GPP release plan (standardization in Figure 7. This ecosystem illustrates how roadmap) is shown in Figure 6. it will become increasingly important in LTE standardization activities to involve not only 5. LTE as an ecosystem infrastructure and device vendors but also Standardization activities targeting LTE vendors in the service and application fields. are not concerned simply with the study and development of LTE technical requirements and 6. Fujitsu standardization protocol specifications. To get telecommunication activities operators to deploy LTE and users to accept it, a Fujitsu has been contributing actively to variety of business segments must be activated. standardization activities surrounding third- That is, standardization activities tied into generation mobile communications systems. It business activation must be promoted. This calls contributed to the founding of 3GPP after being

2008 2009 2010 2011 2012 4Q 1Q 2Q 3Q 4Q 1Q 2Q 3Q 4Q 1Q 2Q 3Q 4Q

EPS (LTE/EPC) Common IMS Rel-8 eCall ETWS (Earthquake and Stage 3 Tsunami Warning System) Home eNodeB Home eNodeB Functional IMS centralized services eMBMS freeze MSR (Multi-Standard Radio) EPS (LTE/EPC) enhancement Rel-9 LIPA Rel-8 stabilization Stage 1 Stage 2 Stage 3 LTE-Advanced Functional Functional Functional Rel-10 Functional freeze SON (Self-organizing NW) freeze freeze freeze Energy saving management Network selection for Rel-10 non-3GPP LTE+ Machine-type Communications

Rel-11 LTE-Advanced MTC (Machine-type Communications) Traffic offloading to cope with traffic growth Heterogeneous network (HetNet), September 2012 Rel-11 Functional freeze Home eNodeB mobility End-to-end QoS/QoE Interworking between 3GPP and data application provider (mobile cloud), IP-PBX, broadband fixed NWs, local area NWs, etc.

Figure 6 3GPP release plan.

100 FUJITSU Sci. Tech. J., Vol. 48, No. 1 (January 2012) A. Noda: Standardization Activities for Next-Generation Mobile Communications Systems

Momentum group Business and general consumer market

Enabler group (Mobile) Operators Rich voice VoIP Enterprise VPNs CS support Standardization bodies Media access Vertical-specific and Internet TV applications

Regulators User device vendors Broadcast Home/consumer mobile TV electronics Infrastructure Service/ Industry Internet-based suppliers content providers Gaming bodies applications

Test equipment Appl. software Improved mobile Transport and manufacturers developers broadband logistics

Complementary Machine-to- Chipset services machine apps manufacturers

VPN: Virtual private network

Figure 7 LTE ecosystem. involved in a range of standardization activities (GSMA) have the role of allocating spectrum and conducted by the ITU, from those for the specifying required system performance, 3GPP Personal Digital Cellular (PDC) system, Japan’s and organizations like the Internet Engineering second-generation mobile communications Task Force (IETF), the Institute of Electrical system, to those for the Future Public Land and Electronics Engineers (IEEE), and the Mobile Telecommunications System (FPLMTS)/ TeleManagement Forum draw up standard IMT-2000. specifications, and the Wholesale Applications Fujitsu has been a member of 3GPP from Community (WAC), the Global Certification its founding and has made many proposals Forum (GCF), and the LTE/SAE Trial Initiative and contributions through its participation in (LSTI) serve as certification bodies. At Fujitsu, the TSG-RAN, TSG-CT, and TSG-SA technical the wireless network business department specification groups. Fujitsu personnel have (Network Business Group), terminal business served as chair and vice-chair of two working department (Ubiquitous Products Business groups (TSG-RAN WG4 and TSG-SA WG2) and Group), and Fujitsu Laboratories work together vice-chair of three technical specification groups to contribute to standardization activities (TSG-RAN, TSG-CT, and TSG-SA). Through deemed necessary for these next-generation these efforts, Fujitsu has come to be recognized mobile communications systems. as the Japanese company that has contributed the most to standardization activities as a 7. Conclusion member of 3GPP. Fujitsu has come to play an increasingly For standardization activities to be bigger role in standardization activities for effective, industry organizations must cooperate mobile communications systems. It has made with each other as they carry out their respective major contributions to the development of global roles (Figure 8). The ITU and the Global standards in the 3GPP since the project began in System for Mobile Communications Association 1998, and it has participated in and contributed

FUJITSU Sci. Tech. J., Vol. 48, No. 1 (January 2012) 101 A. Noda: Standardization Activities for Next-Generation Mobile Communications Systems

3GPP GSMA IEEE ITU-R/ IETF ETSI Plugtests: ETSI group for testing whether products ITU-T conform to ETSI, 3GPP, IETF, and IEEE standards TM Forum ITU: International Telecommunication Union ITU-R: ITU Radiocommunication Sector ITU-T: ITU Telecommunication Standardization Sector GSMA: Global System for Mobile Communications Association WAC IEEE: Institute of Electrical and Electronics Engineers TM Forum: TeleManagement Forum GCF GCF: Global Certification Forum 3GPP: 3rd Generation Partnership Project IETF: Internet Engineering Task Force WAC: Wholesale Applications Community ETSI LSTI LSTI: LTE/SAE Trial Initiative Plugtests ETSI: European Telecommunications Standards Institute Multi Service Forum

Figure 8 Cooperation between industry organizations.

to standardization activities surrounding the standardization bodies. Fujitsu plans to step LTE and LTE-Advanced technologies through up its standardization activities with an eye to the ITU Radiocommunication Sector (ITU-R), achieving convergence between cloud and mobile the ITU Telecommunication Standardization platforms. Sector (ITU-T), the 3GPP, the IETF, and other

Akishige Noda Fujitsu Ltd. Mr. Noda is engaged in standardi­ zation activities targeting mobile communications systems. He serves as vice-chair of the 3GPP TSG-SA and chair of the 3GPP WG in the TTC.

102 FUJITSU Sci. Tech. J., Vol. 48, No. 1 (January 2012)