Infrastructure economics and deployment. Infrastructure economics and deployment

Transcription

1 Infrastructure economics and deployment Jan Markendahl Senior Researcher Project Manager Communication Systems Teacher PhD Student 1 Infrastructure economics and deployment Problem area Dimensioning and cost structure analysis of wide area wireless networks for data services Issues How to satisfy the user Mobile Broadband demand for network coverage, capacity and data rate? How to build networks in a cost-efficient way? Agenda Network dimensioning Cost structure modelling & analysis Exercises on network dimensioning Deployment in urban areas Deployment in rural areas 2 1

2 Group work the overall task For a specific user and traffic scenario you will Make a radio access network design and dimension Analyze the cost structure for different options Transmission Buildout & Site costs Radio Equipment ator 3 Topics Network dimensioning Dimensioning principles User demand and capacity requirements Throughput and capacity in radio access networks Deployment strategies Cost structure modelling & analysis Operator cost structrure Cost structure for networks Price erosion 4 2

3 The dimensioning problem To satisfy the user demand in an area Suburban area Urban area Rural area using different radio access technologies HSPA UMTS GSM 5 The dimensioning problem 6 3

4 Radio Access Technologies (RATs) RAT number RAT Deployment Maximum cell range [km] Urban Rural 1 EDGE 1,00 8,00 2 WLAN 0,03 0,08 3 UMTS Macro 0,60 4,00 4 UMTS Micro 0,15 5 HSDPA Macro 0,4 2 6 HSPA Micro 0,1 7 Average throughput per base station and Peak data rates (Mbps) systems in use!! Radio access technology GPRS/EDGE (2G) UMTS (3G) HSPA (Super 3G) WLAN Peak data rate 0,237 (4 TS) 0, (14.4) 54 Average throughput 0, ,2 0, LTE (4G) LTE (4G) 80 (150) ~

5 Dimensioning of voice capacity Erlang B is the most commonly used traffic model To calculate how many lines that are required if you know the traffic demand during the busiest hour the fraction of blocked calls Call Attempts The bottle neck is busyhour capacity. A normal mobile user calls 100 min/ month outgoing. 00:00 01:00 02:00 03:00 04:00 05:00 06:00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 Time In GSM systems 30 merlang is the statistical traffic per subscriber in busy hour 21:00 22:00 23:00 Minutes of use is the sum of all traffic, i.e. the blue area 9 Network Sharing for UMTS Networks Capacity dimensioning The busy hour Capacity that is deployed Blocked traffic 00:00 01:00 02:00 03:00 04:00 05:00 06:00 07:00 08:00 09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 Call Attempts Time 10 5

6 Dimensioning For voice and RT data you need to estimate the maximum number of ongoing calls or sessions Depends on the arrival rate and the duration of calls Is based on the traffic during the busiest hour For data NRT data traffic the approach with average data rate per user can be used X GB per user and month -> Y kbps per user During 24 hrs all day(s) During 2-8 hours per day 11 Usage & user traffic -> demand for network capacity Amount of data per user, per time unit, per area unit Usage Amount of data per user and time unit e.g.: 100MB per day or 5 GB per month -> need to be expressed as kbps or Mbps per user Traffic Amount of data per time unit per area unit -> is based on user density and usage per user E.g: 100 GB per day in a 2* 2 km area or 10 Mbps per 0,5 sqkm 12 6

7 User density Suburban Urban area Rural area 13 Example of User demand Mbps per sqkm Average data rate per user (Mbps) Number of active users per sqkm 0,01 0, ,1 1,

8 Are these numbers realistic? Population density Stockholm average: 4000/ sqkm Malmö average: 2000/ sqkm Stockholm city: ~25 000/ sqkm Penetration of mobile service 10 % now -> may be 50% in the future Market share of operator ~ 40 % Check!! - With 4% of all users In area with / sqkm => 1000 / sqkm In area with / sqkm => 100 / sqkm 15 Check Order of Magnitude 1000 active users year x/sqkm, 50% market share => deploy capacity year x for 500 users /sqkm 1GB usage per month per user ~ 3kbs per user 24 hours all days for one month; ~ 10 kbs per user during daytime for a month Capacity estimates 1 GB users: ~ 5 Mbps/sqkm 10 GB users: ~ 50 Mbps/sqkm Compare with throughput for one cell 0,3 30 Mbps 16 8

9 Topics Network dimensioning Dimensioning principles User demand and capacity requirements Throughput and capacity in radio access networks Deployment strategies Cost structure modelling & analysis Operator cost structrure Cost structure for networks Price erosion 17 From Ericsson: Capital markets day, May

10 Questions from January meeting? How can capacity be shared between users? Will users at the cell border consume all capacity for other users? What about coverage that varies with cell load? (cell breathing) 19 Example results from Ericsson Review, No1, 2009 For 3GPP Rel

11 Downlink data rates, 3GPP Rel. 7 (Peak rate ~ 28 Mbps) 21 2,2 Mbps 2,2 Mbps Peak rate and capacity (cell throughput) Range and coverage: Data rate depends on the distance from the base station Peak rate = The maximum possible data rate you get IF: The signal quality is very very good Your are alone in the cell The capacity has to be shared between all users in a cell Throughput = The capacity of the cell depends on 1. the spectrum efficiency (SE) of the Radio Access Technology 2. the amount of spectrum 22 11

12 From Ericsson: Capital markets day, May Bit rate and range Impact of Radio Access Technology (RAT) and spectrum RAT 1 RAT 2 RAT 3 For twice the amount of Spectrum (2 X MHz) Macro BS For a given amount of Spectrum ( e.g. X MHz) 24 12

13 Capacity of a a cell as function of Spectral Efficiency and amount of spectrum Spectral efficiency 5 MHz of Spectrum 10 MHz of Spectrum 20 MHz of Spectrum 0,7 bps/hz 3,5 Mbps 7,0 Mbps 14 Mbps 2,0 bps/hz 10 Mbps 20 Mbps 40 Mbps Using a base station site with 3 sectors (cells) will result in a site capacity 3 times higher Example: With 20 MHz of spectrum and a radio access technology with spectral efficiency = 2 bps/hz the site capacity will be 120 Mbps 25 From Ericsson: Capital markets day, May

14 Topics Network dimensioning Dimensioning principles User demand and capacity requirements Throughput and capacity in radio access networks Deployment strategies Cost structure modelling & analysis Operator cost structrure Cost structure for networks Price erosion 27 The dimensioning problem 28 14

15 What to do when the demand increases? 29 What to do when the demand increases? Add carriers Add new sites Sectorize! New target capacity Old capacity 30 15

16 Zander formula (for a given RAT and given amount of spectrum) Csystem c AP N AP c N N AP N user B user A service user the number of access points (base stations) the number of users the average data rate of the users the service area covered (volume indoors) f(q) is a function of the required Quality of Service. B user A service f (Q) 31 Scalability of cellular systems For a specified amount of spectrum and for the same type of radio technology deployment of N times more capacity will imply N times higher costs Deployment for Low or medium data rates (or low Mbs per sqkm) Coverage for high data rates with existing sites Deployment needed for high data rates (or many Mbs per sqkm) 32 16

17 Data rate depends on the signal strength - i.e. range Achievable data rate ~ Signal to Noise ratio ~ 1/ Range α E b ~ N α1 0 d R d = distance from base station R = data rate at distance d Macro BS 33 Rate dependence with distance Assume that a specific data rate R 0 can be achieved at a distance d 0 for a specific (E b /N 0 ) 0 E b ( ) 0 ~ α N 0 0 d 1 R 0 If you want to increase the data rate X times (to Rx) with the same (E b /N 0 ) 0 the maximum distance d x is decreased dx = d 1/α 0 R / R 0 x Examples for α = 3,5 X d x 2 0, , ,

18 Example GPRS Coding scheme Transfer speed depends on the channel encoding used. The least robust, but fastest, coding scheme (CS-4) is available near a base transceiver station (BTS), while the most robust coding scheme (CS-1) Speed (kbit/s) CS CS CS CS is used when the mobile station is far away from a BTS. Using the CS-4 you can get a data rate of 20.0 kbit/s per time slot, but the cell coverage is 25% of normal. 35 Offered bit rate versus coverage & load promised data rate at low level promised data rate at higher level 36 18

19 Data rate depends on the signal strength - i.e. range AND wall penetration losses Achievable data rate ~ Signal to Noise ratio ~ 1/ Range α Most laptop usage is indoors A need to compensate for wall penetration losses -Densermacronetwork -Indoor solutions Macro BS 37 Downtown Stockholm and close to here 38 19

20 Topics Network dimensioning Dimensioning principles User demand and capacity requirements Throughput and capacity in radio access networks Deployment strategies Cost structure modelling & analysis Operator cost structrure Cost structure for networks Price erosion 39 Cost structure for a traditional mobile network operator (US ) Cost structure of US mobile operators % 35% Networks M&S CRM & Billing 30% 25% 20% 15% 10% 5% 0% Network opex and depreciation Customer acquisition costs Administration and customer support Source: Operator reports Opex Depreciation 40 20

21 Parameters and Cost structure For the dimensioning you need performance and cost parameters for different kinds of radio access systems The cost structure includes both CAPEX and OPEX Radio access equipment Transmission equipment Site and build out costs Installation Site lease Power Leased lines 6% 10% 14% 15% 2% 8% 24% 14% 7% Telecom equipment Transmission equipment Site equipment Civil works Network rollout O&M Site rental Power Spares, support, training 41 Cost structure of base stations /access points (from Klas Johansson) 1,00 0,80 0,60 Discounted cost structure CAPEX+OPEX (new sites) Backhaul transmission Site buildout, installation + lease Radio equipment, O&M, power 0,40 0,20 0,00 Macro Micro Pico WLAN Average throughput Range [1-9] x 2.5 Mbps 1000 m [1-2] x 2.5 Mbps 250 m 2.5 Mbps 100 m 22 Mbps 25 m 42 21

22 Example - Homework description Assumed cost and capacity Cost [k ] Capacity [Mbps] UMTS Macro BTS, omni 20 1 UMTS Macro BTS, additional sector 10 1 UMTS Macro BTS, additional carrier 20 1 UMTS Micro BTS, one sector 10 1 HSDPA Macro BTS, omni 25 3 HSDPA Macro BTS, additional sector 10 3 HSDPA Macro BTS, additional carrier 25 3 HSDPA Micro BTS, omni Example - Homework description Installation and buildout costs Cost [k ] EDGE/UMTS/HSDPA Macro BTS site installation 30 UMTS/HSDPA Micro BTS site installation 20 EDGE/UMTS/HSDPA Macro BTS site buildout RURAL 70 UMTS/HSDPA Macro BTS site buildout URBAN 40 UMTS/HSDPA Micro BTS site buildout URBAN 20 WLAN AP installation + buildout

23 Is valid for electronics, i.e. the base stations Is NOT valid for masts, towers (steel), power, labour, site leases etc Moores law Even if the radio eq. was for free the sites are costly 45 Cost of radio equipment is decreasing rapidly 512 MSEK (50 MEuro) ~6 KEuro per base station ~ 750 MSEK 46 23

24 Infrastructure economics and deployment Problem area Dimensioning and cost structure analysis of wide area wireless networks for data services Agenda Network dimensioning Cost structure modelling & analysis Exercises on network dimensioning Deployment in urban areas Deployment in rural areas 47 24