I’ve a use case where I need to provide Fixed Wireless Access. I’m considering to use a Nova 243 and a CPE CAT6. Nova 246 doesn’t fit here since to support B42 it would be only under customization and I dont have enough volume. I’ve the following requirements:
B42
3 x Sectors
80 users per Sector
Peak speed per user : 25Mbps on DL and 2Mbps on UL
Village located from 15 to 20km far away from the radio tower.
So, I know that the Nova243 only support one sector, so the bare minimum would be 3 x Nova 243 on this radio tower. But to fullfill the data rate requirement with that number of users per sector, I guess that I would need not 3 x Nova 243 but at least 6 units of the Nova 243. Am I right? How can I properly size the Nova243 capacity to these requirements?
Renato, the rough formula for capacity is “net sector capacity divided by service rate subscribed times the oversubscription ratio”.
In your case, your net sector capacity is going to be very low because you are reaching at least 15km to get to your subscribers, so I don’t believe at that range you can support 25 Mb/s DL. My quick calculation says your DL RSRP will be around -113 dBm or lower, which supports QPSK data rate. And, since the UL system gain is about 9 dB lower than the DL system gain, you will have issues supplying 2 Mb/s UL capacity. My advice is to find or build a tower as close to your subscribers as possible. Then you can support the service level and number of UE’s per sector to meet your system goal.
Considering the Nova243 max power output (40dBm) what would max distance acceptable for these requirements? If necessary maybe we can assume that instead of 3 sectors (3xNova243) we can design the solution to work with 6 smaller sectors (6xNova243). Would this be viable?
Assuming that the distance could be reduced then, how could I estimate a realistic number of users per sector supported with that data rate requirement? I mean according to the datasheet we have the below capacity for one sector: 20 MHz: - SA0: DL 50 Mbps, UL 42 Mbps - SA1: DL 80 Mbps, UL 20 Mbps - SA2: DL 112 Mbps, UL 14 Mbps
Considering SA2, what would be a reasonable assumption for the “service rate subscribed” and the “oversubscription ratio” ?
The Service Rate subscribed is your 25 Mb/s target rate to your subscribers.
Considering subframe 2 (SA2), most sectors average maximum data rate is 70-80 Mb/s – assuming 90% of the UE’s connected have a very good link quality. For most networks without using a device such as Preseem to limit streaming bandwidth, average oversubscription ratios are 5:1 up to 8:1. Using a device like Preceem, you can achieve 10:1 or higher OS ratio.
Crunching this math, you can comfortably serve 25-30 UE’s per sector with no bandwidth shaping, and 30-40 UE’s when you incorporate the UE’s MIR with bandwidth shaping. LTE will allow you to connect more subscribers, but the issue will be saturation at peak data periods.
Switch to 30 degree antennas and run 6 sectors (40 users per sector) or 4 sectors at 45 degrees, so 60 users per sector.
Why don’t you setup a link to another tower much closer. You could use 24GHz PT to PT radios would give you a 2Gbps link up to about 7-8Km and a 1Gbps for your 13-15 km, or a slower link at 768Kbps for the 20km?
