Meshed Backhauling of Small Cells Using IEEE ad at 60GHz. EUCNC 2018 Peter Legg and Ray McConnell

Transcription

1 Meshed Backhauling of Small Cells Using IEEE ad at 60GHz EUCNC 2018 Peter Legg and Ray McConnell

2 Outline Introduction to millimetre-wave meshed backhaul and IEEE ad Deployment scenario System simulator Simulation results 2

3 Millimetre-wave meshed backhaul Modem has steerable phased array antenna X 60 GHz, span up to 500m 3

4 Why millimetre-wave mesh? 1. To connect nodes that are not in line-of-sight (LOS) Essentially a LOS technology today 2. To provide resilience Mesh provides alternative paths to the POP 3. To load balance Distribute traffic across multiple paths to increase throughput 4. Range extension Range is sufficient for typical dense urban deployments, but could daisy chain nodes to reach outlying small cells 4

5 Standard completed in 2012 Operates in unlicensed 60 GHz band Up to four 1.76GHz channels IEEE ad Initially targeted indoor use-cases, WiGig Blu Wireless (and others) have recognised its application for backhaul of small cells, fixed wireless access, and V2I IEEE ay is developing enhanced capabilities, with MIMO, channel bonding and improved support for infrastructure applications 5

6 Modems (STA) are grouped into multiple PBSS (Personal Basic Service Set) A PBSS is managed by one modem, the PBSS Control Point (PCP) The PCP controls which STAs communicate Scheduled access to the air TDD IEEE ad MAC Note that there is no meshing defined in IEEE ad 6

7 Deployment scenario: small cell backhaul 133m Dense urban environment Eixample region of Barcelona Use millimetre-wave backhauling from each small cell to a POP (point of presence) 1 POP per macro cell site, or 1 POP at macro site 8 only 7

8 System Simulator The simulator follows a sequence of steps: 1. Calculate the path gain matrix between nodes. 2. Design the PBSSs and assign channels. 3. Perform route calculation and static simulation to give indicative network performance (e.g. link rates, SNR, SINR). 4. Perform dynamic system simulation in which packets are generated, routed over the mesh with queueing and scheduling for each wireless hop 8

9 Simulation Tool Chain Outputs Inputs Ray tracing model Path gains (including antenna gains) when node pairs beamform to each other Link Interference matrix o o KPI: Link rates with interference Max. throughput per node with equal traffic to all nodes KPI: o Mean throughput per node o Latency per packet Node locations (x,y,z coordinates) POP locations Free-space radio model PBSS Calculator Static Performance Evaluation Dynamic simulation Network topology with PBSS and Node configuration Input Parameters Number of channels (fullband/halfband) Interference model Routing method 9

10 Simulation Campaign # POPs Reuse Comment 3 1 Will the mesh work with a single 60GHz channel? 3 3 What performance benefits are there from using multiple channels? Needs colouring algorithm in PBSS Designer 1 3 Increase the hop count and the depth of the tree 11

11 System simulation results: reuse 1, 3 POPs (1/3) POP Circle indicates PCP PBSS Design Preferred routes 12

12 System simulation results: reuse 1, 3 POPs (2/3) Interference Analysis SNR and SINR per link Link rates with and without power control 13

13 System simulation results: reuse 1, 3 POPs (3/3) Mean throughput per node Mean latency per node Max latency per node Dynamic simulation: the source traffic rate per node (uplink) was set to 100 Mb/s, and the sink rate (downlink) 450 Mb/s. Latency approx. 0.5ms per hop too large to support CPRI 14

14 System simulation results: reuse 3, 3 POPs (1/1) Reuse 1 We can increase the traffic rates, to 750 Mb/s (DL) and 250 Mb/s (UL). Interference is markedly reduced, with many links being thermal noise limited All routable links now work at MCS12. 15

15 System simulation results: reuse 3, 1 POP (1/1) Single POP at node 8 16

16 Comparison 17

17 Conclusions Presented a system simulator and its use to evaluate a meshed backhaul of small cells at 60 GHz Challenging environment with grid deployment Even with a single channel it is possible to backhaul all the small cells. 450 Mb/s downlink, 100 Mb/s uplink per cell The latency is approximately 0.5 ms per hop. Using more channels increases the achievable backhaul rates. The latency depends largely on the number of hops, so is driven by the number of POPs deployed rather than the number of channels used. 18