DISTRIBUTION AND BACKHAUL

Transcription

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2 DISTRIBUTION AND BACKHAUL USING WHITE SPACE 3G WHITE SPACES WIFI FIBER BACKHAUL NETWORK 2

3 OUTLINE Our proposed system First order Methodology Achievable Capacity Traffic Demand How many cells would need fiber? Aggregating flows Conclusion and future work 3

4 NJ as case study Proximity to NY & Philly Highest population density in NJ! Cells of 5 mi X 5 mi total 307 Antenna (base-station) in each FCC s max allowed height=30 m FCC s max TX power=4 W Based on fixed devices rules of FCC HOW WILL IT LOOK? 4

5 WHAT WILL IT DO? Antenna coverage Use of Sector antennas for more concentrated transmission Fiber Internet user Wifi Wireless Distribution and Backhaul 4 sector antennas

6 CAN WHITE SPACES BE USED? FIRST ORDER CRITERION ACHIEVABLE CAPACITY AVAILABLE BANDWIDTH Resources used: (PER CELL) > <Use Radio SPECTRAL EFFICIENCY RECEIVED SNR.. DEMAND Use Fiber (PER CELL) TX POWER NOISE PATH LOSS FCC rules? Propagation models NJ pop statistics Census ? Internet usage statistics Internet? traffic survey

7 NJ TOWERS AT A GLANCE Towers in NJ, NY, DE & PA Coverage can be 100km (r) AVAILABLE BANDWIDTH 7

8 AVAILABLE BANDWIDTH FCC S PROTECTION RULE Secondary White Space radio Primary TV tower Protected radius Additional separation ring 8

9 CHANNEL AVAILABILITY AVAILABLE INCLUDING SPACE PER ADJACENT CHANNEL CHANNEL EFFECT TV tower coverage Additional separation ring Available for possible use Available as White Spaces AVAILABLE BANDWIDTH

10 AVAILABLE BANDWIDTH BANDWIDTH DATABASE 25 Repeat this for each cell and you get bandwidth database Each channel is 6 MHz 7 31 channels available per cell ( MHz) X No islands Similar channels available in neighboring cells INTERFERENCE! 10

11 AVAILABLE BANDWIDTH FREQUENCY REUSE PLANNING reuse factor (r) of 2 : cell-1 cell-2 cell-3 cell-4 cell-5 SNR at cell-2 = 19 db SNR at cell-4 = 5 db Interference 14 db isolation for r=2 Median path loss: ITU terrain model for LOS Obstruction height:15m for sparse population and 30m for dense population 1% outage with 8 db shadowing variance 11

12 ACHIEVABLE CAPACITY > < DEMAND AVAILABLE BANDWIDTH BANDWIDTH DATABASE SPECTRAL EFFICIENCY RECEIVED SNR TX POWER 4W (6dB) NOISE Thermal (-136dB) + Noise Figure (10dB) PATH LOSS ITU Terrain 12

13 LET S CONSIDER ONE CELL 54 MHz (9 channels) available 27 MHz usable (reuse) Spectral Efficiency: 6.23 bps/hz (path loss and population and building heights) Max Achievable Capacity: ~168 Mbps ~75.7 GB/hour 13

14 ACHIEVABLE CAPACITY > < DEMAND US Census 2000 Our Approximation USAGE PER HOUSEHOLD SIMULTANEOUS ACTIVE USERS (α) Pop/sq mi pop/cell 3 people per household 74.2% have internet internet clients/cell 18MB/hr (Cisco Survey) 90 MB/hr (5 times more) 126 MB/hr (7 times more) 180 MB/hr (10 times more) 14 α = 10% α = 30% α = 50%

15 LET S CONSIDER ONE CELL Cell pop: 8750 Cell households: 2917 Cell internet connections: 2164 Cell traffic using α = 30% : 18 MB/hr/link: 11.7 GB/hr 90 MB/hr/link: 58.4 GB/hr 126 MB/hr/link: 81.8 GB/hr 180 MB/hr/link: GB/hr 15

16 LET S CONSIDER ONE CELL ACHIEVABLE CAPACITY > < DEMAND α = 30% & 18 MB/hr/link : 75.7 > 11.7 α = 30% & 90 MB/hr/link : 75.7 > 58.4 α = 30% & 126 MB/hr/link : 75.7 < 81.8 α = 30% & 180 MB/hr/link 75.7 < : 16

17 HOW MANY CELLS NEED FIBER? (OUT OF 307) per hour α = 10% α = 30% α = 50% 18MB MB MB MB MB/hr 90MB/hr 126 MB/hr 180 MB/hr Cells requiring fiber connection 17

18 AGGREGATING MULTIPLE FLOWS CLUSTER HEAD 18 Proposed Solution: Use Excess Capacity for aggregation Excess Capacity = Achievable Capacity - Demand Clustering Plant more fiber at cluster heads Plant cluster heads in high capacity cells to route traffic through Detailed routing study

19 EXAMPLE OF AGGREGATION Group cells into clusters (illustrated in figure) Have 1 fiber connected cell in each cluster If in each cluster: Excess Capacity > Total Demand X (2 or 3) Then: 1 fiber per cluster is sufficient! Else: Add 1 fiber to cluster After calculations for α = 30% & 126 MB/h: WORST CASE REQUIRES 10 MORE FIBER CELLS 19

20 CONCLUSIONS AND FUTURE WORK Feasibility study of a distribution plan in NJ First order study promising in spite of conservative assumptions on traffic and propagation system more cost effective than a fiber layout Most effective in rural areas (where it s needed) No prior high speed internet connectivity No fiber infrastructure More bandwidth available and better propagation Same methodology for other states/regions Further issues that need to be studied: Detailed routing strategies Cost/benefit analysis 20

21 THANK YOU QUESTIONS? 21