IMT2000 IMT2000 stands for IMT International Mobile Communications

IMT-2000 • IMT-2000 stands for IMT: International Mobile Communications 2000: the frequency range of 2000 MHz and the year 2000 • In total, 17 proposals for different IMT-2000 standards were submitted by regional SDOs to ITU in 1998. 11 proposals for terrestrial systems and 6 for mobile satellite systems (MSSs). • All 3 G standards have been developed by regional standard developing organizations (SDOs). • Evaluation of the proposals was completed in 1998, and negotiations to build a consensus among different views were completed in mid 1999. All 17 proposals have been accepted by ITU as IMT-2000 standards. The specification for the 1 Radio Transmission Technology (RTT) was released at the end of 1999.

IMT-2000 • The (IMT-2000), consists of 3 operating modes based on Code Division Multiple Access (CDMA) technology. • 3 G CDMA modes are most commonly known as: – CDMA 2000, – WCDMA (called UMTS) and – TD-SCDMA (Time Division-Synchronous Code Division Multiple Access) 2

High-Speed Packet Data Services • 2 Mbps in fixed or in-building environments (very short distances, in the order of metres) • 384 kbps in pedestrian or urban environments • 144 kbps in wide area mobile environments • Variable data rates in large geographic area systems (satellite) 3

4

Network Elements from UMTS differs from GSM Phase 2+ (GSM +GPRS) mostly in the new principles for the air interface transmission WCDMA instead of TDMA/FDMA Therefore a new RAN (Radio Access Network) called: UTRAN (UMTS Terrestrial Radio Access Network) must be introduced with UMTS Only minor modifications are needed in the CN (Core Network) to accommodate the change 5

UTRA: UMTS Terrestrial Radio Access The most significant change in REL. ´ 99 was the “UTRAN”, a W-CDMA radio interface for land-based communications. UTRAN supports time (TDD) and frequency division duplex (FDD). The TDD mode is optimized for public micro and pico cells and unlicensed cordless applications. The FDD mode is optimized for wide-area coverage, i. e. public macro and micro cells. Both modes offer flexible and dynamic data rates up to 2 Mbps. 6

UMTS architecture UTRAN (UTRA NETWORK) • Radio Network Subsystem (RNS) UE (User Equipment) CN (Core Network) Uu UE Iu UTRAN CN 7

UTRAN Two new network elements are introduced in UTRAN • RNC • Node B UTRAN is subdivided into individual radio network systems (RNSs), where each RNS is controlled by an RNC. The RNC is connected to a set of Node B elements, each of which can serve one or several cells. 8

UTRAN architecture RNS UE 1 Node B Iub RNC: Radio Network Controller RNS: Radio Network Subsystem Iu RNC CN UE 2 Node B UTRAN comprises several RNSs UE 3 Node B Iur Iub RNC Node B RNS Node B can support FDD or TDD or both RNC is responsible for handover decisions requiring signaling to the UE Cell offers FDD or TDD

UTRAN functions • • • Admission control Congestion control Radio channel encryption Handover Radio network configuration Channel quality measurements Radio resource control Data transmission over the radio interface Outer loop power control (FDD and TDD) Channel coding 10

Core network The Core Network (CN) and the Interface Iu, are separated into two logical domains: q. Circuit Switched Domain (CSD) q. Packet Switched Domain (PSD) • Circuit switched service incl. signaling • Resource reservation at connection setup • GSM components (MSC, GMSC, VLR) • Iu. CS BTS Abis BSS BSC Node BTSB • GPRS components (SGSN, GGSN) • Iu. PS VLR Iu MSC Iu. CS Node B PSTN Au. C EIR Node B GMSC HLR GR Iub RNC RNS SGSN Iu. PS Gn GGSN Gi CN

Access method CDMA • CDMA (Code Division Multiple Access) – all terminals send on the same frequency probably at the same time and can use the whole bandwidth of the transmission channel – each sender has a unique random number, the sender XORs the signal with this pseudo random number – the receiver can “tune” into this signal if it knows the pseudo random number, tuning is done via a correlation function

Spreading and scrambling of user data • Constant chip rate of 3. 84 Mchip/s • Different user data rates supported via different spreading factors – higher data rate: less chips per bit and vice versa • User separation via unique, quasi orthogonal scrambling codes – users are not separated via orthogonal spreading codes – much simpler management of codes: each mobile can use the same orthogonal spreading codes data 1 data 2 data 3 data 4 data 5 spr. code 1 spr. code 2 spr. code 3 spr. code 1 spr. code 4 scrambling code 1 sender 1 scrambling code 2 sender 2

Length SPREADING FACTOR

DS-CDMA= Direct Sequence Code Division Multiple Access

3. 84 Mchip/s

CDMA in theory • • Sender A – sends Ad = 1, key Ak = 010011 (assign: „ 0“= -1, „ 1“= +1) – sending signal As = Ad * Ak = (-1, +1, -1, +1) Sender B – sends Bd = 0, key Bk = 110101 (assign: „ 0“= -1, „ 1“= +1) – sending signal Bs = Bd * Bk = (-1, +1, -1) Both signals superimpose in space – interference neglected (noise etc. ) – As + Bs = (-2, 0, 0, -2, +2, 0) Receiver wants to receive signal from sender A – apply key Ak bitwise (inner product) Ae = (-2, 0, 0, -2, +2, 0) Ak (-2, 0, 0, -2, +2, 0) (-1, +1, -1, +1)= 2 + 0 + 2 + 0 = 6 • result greater than 0, therefore, original bit was „ 1“ – receiving B Be = (-2, 0, 0, -2, 2, 0) Bk ( -2, 0, 0, - 2, 0) (1, 1, -1, +1) = -6, i. e. „ 0“

CDMA on signal level I data A 1 0 1 Ad key A key sequence A data key 0 1 0 1 1 0 0 1 1 Ak 1 0 1 1 1 0 0 0 1 1 0 0 signal A Here the binary ” 0” is assigned a positive value, The binary ” 1” a negative value! Real systems use much longer keys resulting in a larger distance between single code words in code space. As

CDMA on signal level II signal A +1 -1 1 data B key sequence B +1 -1 +2 As + B s 0 0 Bd 0 0 0 1 1 0 1 0 1 1 1 Bk 1 1 1 0 0 0 0 1 1 1 data key signal B As 0 -2 Bs

CDMA on signal level III data A 1 0 1 +2 As + B s 0 -2 1 Ak -1 +2 (As + Bs) * Ak 0 -2 integrator output comparator output Ad

CDMA on signal level IV data B 1 0 0 As + B s Bk (As + Bs) * Bk integrator output comparator output Bd

CDMA on signal level V +2 As + B s 0 -2 wrong key K +2 (As + Bs) 0 *K -2 integrator output comparator output (0) ?

OSVF coding Ortogonal Variable Spreading Factor Codes 1, 1, 1 Recursive rule 1, 1, -1, 1, 1, -1. . . 1, 1, -1, -1, -1, 1, 1 1 1, -1, 1, -1 X, -X SF=n 1, 1, -1, -1, -1 1, 1 X, X X . . . 1, 1, 1, 1 . . . 1, -1, -1, 1 1, -1 SF=2 n 1, -1, 1, 1, -1, 1. . . 1, -1, -1, 1, 1, -1 SF=2 SF=4 SF=8

Support of mobility: macro diversity • Multicasting of data via several physical channels – Enables soft handover – FDD mode only • Uplink UE Node B RNC – simultaneous reception of UE data at several Node Bs CN • Downlink – Simultaneous transmission of data via different cells

Transmit Power Control is essential Near – far problem despreading MS MS Node B Power control despreading MS Transmit Power Control MS Minimize the Tx power Node B More secure Increase the system capacity

Frequency Allocation FDMA / TDMA f 2 f 1 f 3 f 2 CDMA f 1 f 3 f 2 f 1 f 3 A case of 3 cell repetitions f 1 f 3 f 1 f 1 f 1 f 1 f 1 Same frequency in all cells. 27

UMTS protocol stacks (user plane) UE Uu UTRAN Iu. CS 3 G MSC apps. & protocols Circuit switched RLC MAC radio UE Packet switched apps. & protocols IP, PPP, … PDCP SAR AAL 2 ATM Uu UTRAN Iu. PS 3 G SGSN IP tunnel Gn 3 G GGSN IP, PPP, … GTP RLC GTP UDP/IP MAC AAL 5 L 2 radio ATM L 1 PDCP GTP UDP/IP

EDGE Enhanced Data rates for GSM Evolution • ECSD - Enhanced CSD (Circuit Switched Data) • EGPRS - Enhanced GPRS • For higher data rates • New coding and modulation schemes • The base stations need to be up dated • EGPRS up to 384 kbps (48 kbps per time slot) • ECSD 28. 8 kbps 29

Modulation 30

The Beauty Contest Ten companies asked for one out of four licences Licences were given to • Vodaphone • Tele 2 • Hi 3 G • Orange The incumbent, Telia, was not given a licence!!! 31

UMTS in Sweden The licensees have to cover 8 860 000 inhabitants. Two joint ventures: Svenska UMTS nät - Tele 2 and Telia and Tele 2 have established a joint venture, Svenska UMTS nät, with a common 3 G network. 3 GIS – Telenor and 3* To meet the regulatory requirements, Telenor and 3 has build individual networks, and each has to cover 30% of the population. Telenor and 3 have established a joint venture, 3 G Infrastructure Services (3 GIS) with a common shared network. This network covers approximately 70% of the population. 32 Björkdahl & Bohlin

Network coverage Theoretically it is possible to cover 8 860 000 inhabitants by covering 20 400 km² of Sweden’s surface area. (Swedish total area is 411 000 km². ) Theoretical level corresponds to a coverage of 5% of the Swedish area. In practice, it seems reasonable that the operators will aim for a total coverage of around 170 000 km². This corresponds to a coverage of 41% of the Swedish surface area. The operators will be able to cover all urban areas and 84% of the inhabitants by covering around 11 000 km². This corresponds to a coverage of 2. 7% of the Swedish surface area. 33

Investment for an average operator Comparing Germany, United Kingdom and Sweden The table shows the average 3 G investment per capita per year, including applicable license fees, in Sweden, Germany and the UK for an average operator in each country, for the entire license duration. 7. 5 USD 6. 2 USD 3. 8 USD 1 USD = 8 SEK 34

Summary of main findings • The average 3 G network investment per operator is estimated to be SEK 6. 1 billion. • The total 3 G network investment in Sweden is estimated to be SEK 24 billion. • If the Swedish joint ventures co-operate in rural areas the total 3 G network investment is estimated to be SEK 19 billion. 35

End of Chapter 36