Challenges in Future Wireless Broadband Access Networks

Transcription

1 Challenges in Future Wireless Broadband Access Networks C1 Öffentlich / Public Version 1.0 Dr. Andreas Jungmaier Network Strategy & Assessment / TNS Vodafone D2 The Future of Broadband Wireless 26. Treffen der ITG Fachgruppe Düsseldorf,

2 Agenda Access architectures technology brief Drivers and requirements in future access networks Infrastructure options for the future access Leased Lines DSL Microwave Links Fibre to the Node Switching technologies in the future access ATM MPLS and Pseudowire Emulation Edge-to-Edge (PWE3) Carrier Ethernet Outlook and conclusion 2 Challenges in Future Broadband Wireless Access

3 Access architectures technology brief (i) 2G BSS is TDM based Circuit switched voice BTS GPRS / EDGE Um BTS BSC A Low connection capacities typically PDH: 1 x E1 BTS 2G - BSS Gb MSC mostly microwave links or leased lines Uu Node B Node B Iub Iub RNC Iucs Iups SGSN 3G RNS is typically ATM based R 99 circuit switched voice R 99 packet switched Data Node B Iub Iub RNC Rel.5/6 HSDPA/HSUPA packet switched data Node B 3G - RNS Medium connection capacities typically PDH: 1-8 x E1 Radio Access Network Core Network mostly microwave links or leased lines 3 Challenges in Future Broadband Wireless Access

4 Access architectures technology brief (ii) 3G RNS is ATM and IP based as per Rel-5, native Iub over IP may be used ATM is not ruled out, however Rel.5/6 HSDPA/HSUPA packet switched data suggest higher connection bandwidths Medium connection capacities typically PDH: 1-8 x E1 mostly microwave links or leased lines 4G RAN is IP based with a flat architecture base stations and core network gateways this is true for mobile WiMAX and 3GPP Long Term Evolution (LTE) High connection capacities! Ethernet based 4 Challenges in Future Broadband Wireless Access

5 New technologies push peak access bandwidth requirements Theoretical peak data rate [Mbps] Average peak user data rate [Mbps] Channel bandwith [MHz] 3.6 Mbps x5 HSDPA 7.2 Mbps 14.4 Mbps x5 2x5 HSPA x5 LTE x10 mwimax Good to know Maximum data rate under ideal conditions Peak user data rate can be misleading and depend on different factors (distance from the base station, active users and interference situation) Reflects customer experience Based on spectral efficiency calculations Influenced by channel bandwidth and spectral efficiency Amount of spectrum used for the radio link Is fixed to 5 MHz for UMTS, scalable for all revolutionary technologies up to 20 MHz ADSL 2+ VDSL Average user data rate= Spectral Efficiency channel bandwidth (mobile) No. of sectors per site Average maximum data rate (fixed) 5 Challenges in Future Broadband Wireless Access

6 Next generation radio networks will require Ethernet/IP connectivity with capacities between 50 and 200 Mbps 6 Challenges in Future Broadband Wireless Access

7 Infrastructure Options for Future Access (i) P R O C O N Leased Lines Last resort solution where nothing else works Low CAPEX Direct termination at controller site possible (BSC, RNC, etc.) High OPEX Low bandwidth (1xE1) Higher bandwidths (E3, STM-1) are extremely expensive Ethernet not supported out of the box terminal equipment may be needed for IP/Ethernet support Low guaranteed availability xdsl Low CAPEX Lower OPEX than Leased Lines An option for leased line replacement High bandwidths in the future Bandwidth depends on length of local loop Maximum reach about 5 km from central office Carrying PDH/ATM and Ethernet at the same time is not trivial Cost-efficient backhaul needed from central office to controller site Low guaranteed availability 7 Challenges in Future Broadband Wireless Access

8 Infrastructure Options for Future Access (ii) - DSL P R O C O N xdsl Low CAPEX Lower OPEX than Leased Lines An option for leased line replacement High bandwidths in the future Bandwidth depends on length of local loop Maximum reach about 5 km from central office Carrying PDH/ATM and Ethernet at the same time is not trivial Cost-efficient backhaul needed from central office to controller site Low guaranteed availability Data Rate [Mbps] ADSL2+ high data rates VDSL/VDSL2 ADSL(2) gshdsl.bis SHDSL.bis Long Loop Line Length [km] SHDSL offers symmetrical services at long distances from the central office gshdsl.bis enhances the symmetrical bandwidth per copper pair and allows the bonding of up to 4 pairs 5 8 Challenges in Future Broadband Wireless Access

9 Infrastructure Options for Future Access (iii) Microwave Links P R O Low OPEX High bandwidths can be realised Next generation microwave links provide hybrid transport of PDH and Ethernet High availability (>99.99%) P2P and PmP systems available Dynamic modulation can adapt to link conditions Modulation QAM Typical Peak Capacity [Mbps] 4 40 Example : Packet radio system capacity with 28 MHz channel spacing C O N High CAPEX Line of sight needed Frequencies are regulated by BNetzA E1/TDM IP/Eth GFP PDH Radio Frame 9 Challenges in Future Broadband Wireless Access

10 Gigabit microwave links will be available in the near future Point-to-point links using millimeter waves (aka the E-band) between 60 GHz and 80GHz ETSI approval is ongoing Large blocks of frequency spectrum can be used Narrow line of sight beams high spectrum reusability may be a supplement to fiber optics, especially in metro areas low range (1 to 4 km) because of high attenuation Gigabit over the Air GHz Source: Gigabeam 10 Challenges in Future Broadband Wireless Access

11 Infrastructure Options for Future Access (iv) Fibre to the Concentrator/Node P R O Medium CAPEX Low OPEX for fibre lease High bandwidth can be realised Bandwidths can be enhanced easily Node B Optical CPE STM-1 dark fibre C O N High costs for civil works depending on length of new fibres Cost-efficient backhaul needed from central office to controller site Realisation and planning comparably complicated Central Office Optical Switch A Fibre Network of Local Carrier Optical Switch RNC Availability can be critical 11 Challenges in Future Broadband Wireless Access

12 Early and cost-efficient switching is key for the success of the future mobile broadband wireless access network 12 Challenges in Future Broadband Wireless Access

13 Switching technologies in the future access (i): ATM ATM is standardised for 3G Iub User data typically transported over AAL2 (CBR, rt-vbr, UBR) Signalling data transported over AAL5 2G traffic can be carried using ATM Circuit Emulation Service (CES) Ethernet or IP can be transported, e.g. as Classical IP over ATM (CLIP) or LAN Emulation (LANE) large overheads (AAL5, ATM headers) ATM switching capacity and interfaces are expensive compared to MPLS or Ethernet early aggregation is difficult ATM may not be optimal for a data centric 4 th generation RAN 13 Challenges in Future Broadband Wireless Access

14 Switching technologies in the future access (ii): MPLS and Pseudowire Emulation Edge-to-Edge (PWE3) 2G TDM and ATM cells are carried over MPLS VPNs that implement PWE3 tunnels MPLS is not a must, but typically used for PWE3 Solution allows an All-IP backhaul early aggregation gains can be achieved over all technologies PWE3 incurs additional overheads and delays MPLS and PWE3 headers buffering delays for packetisation Probably works best with high bandwidth links > 50 Mbps New PWE3 gateways are needed at most concentrator sites (CAPEX!) PWE3 is probably a good solution for a green-fielder with small existing install base Option 1 2G: TDM/PDH 3G: ATM-IMA 4G: IP/Ethernet Option 2 2G: TDM/PDH 3G: Iub/IP/Ether 4G: IP/Ethernet Local & Metro Backhaul base station site (2G, 3G, 4G) Regional Backhaul 2G: TDM/PWE3/MPLS/Eth/SDH 3G: ATM/PWE3/MPLS/Eth/SDH 3G: Iub/IP/Ethernet/SDH 4G: IP/Ethernet/SDH PWE 3 Tunnels PWE3 Gateway encapsulates all data in MPLS VPN tunnels RNC concentrator 14 Challenges in Future Broadband Wireless Access

15 Switching technologies in the future access (iii) Carrier Ethernet Carrier Ethernet enhances traditional Ethernet transport by providing Ethernet Virtual Connection (EVC) services like P2P E-Line and PmP E-LAN (multipoint layer 2 VPNs) this may be useful, e.g. for handover traffic between 4G base stations Circuit Emulation Service (for E1) better management options Small Eth switches are integrated in NodeB or microwave equipment allows early aggregation gains Parallel Carrier Ethernet infrastructure can be established step-by-step Ethernet works everywhere (PDH, DSL, Microwave Radio, Fibre) But: requires management of three separate switching infrastructures! Carrier Ethernet is probably a good solution for enhancement of a large existing install base Option 1 Local & Metro Backhaul 2G: TDM/PDH 3G: ATM-IMA 4G: IP/Ethernet 2G: TDM/PDH 3G: Iub/IP/Ether 4G: IP/Ethernet Option 2 base station site (2G, 3G, 4G) Regional Backhaul 2G: TDM/SDH 3G: ATM/SDH 3G: Iub/IP/Eth/SDH 4G: IP/Eth/SDH * RNC * or: off-load Ethernet traffic to another medium (VDSL, Fibre etc.) concentrator 15 Challenges in Future Broadband Wireless Access

16 Key conclusions 1 There are plenty of options to choose from: future mobile access networks will become more diverse just like the radio technologies they support. 2 Future traffic demands drive high bandwidth capabilities in Gbps region at concentrator sites. A trade-off between all available media is necessary, taking into account individual costs. 3 Technology trends and increasing packet switched data traffic suggest that future mobile access solution should be optimised for IP/Ethernet traffic, not forgetting the legacy install base 4 Early switching is key to the success of the future mobile broadband access networks since an early aggregation could be achieved thus relieving the regional backhaul links. 16 Challenges in Future Broadband Wireless Access