Thursday, 15 October 2015

LTE Capacity (1)

LTE Efficiency vs. Bandwidth

LTE maintains high efficiency with bandwidth down to 5 MHz
The differences between bandwidths come from frequency scheduling gain and different Overheads
 Voice Spectral Efficiency Evolution from GSM to LTE
            GSM-EFR is a speech coding standard that was developed in order to improve the quite poor quality of GSM-Full Rate (FR) codec. Working at 12.2 kbit/s the EFR provides wirelike quality in any noise free and background noise conditions.3 GPP (R2-073487): Supporting CS over HSPA improvements in user plane latency and  system capacity
 Theoretical LTE Peak Data Rates 
  Downlink: Peak Rate 172 Mbps with 2x2 MIMO and 20 MHz
 Uplink: Peak Rate 57 Mbps with 20 MHz and 16QAM
Capacity dimensioning (Peak Throughput)


Cell Edge Data Rate Simulations


Latency Evolution
-Internet-HSPA provides further improvement in latency 
-WiMAX latency expected 30 ms 
-Reference: DSL can provide <10 ms round trip time

Burst Error Rate (BLER) vs. SNR


LTE Cell  Coverage


LTE 3-sector vs 6-sector

LTE 6-sector site solution reduces the number of coverage sites by ~35%

 LTE 6-sector site solution gives a benefit of larger coverage (mainly due to higher gain antennas) and different network layout
It can happen that average interference level is higher from the point of a single cell nevertheless 6-sector solution requires 35% less sites compared to corresponding 3-sector configuration
 6-sector Solution for +80% More Capacity
  -6-sector solution is widely used today in Nokia networks today 
- BTS allows very compact site solution with 6 sectors 
One system module 
Two RF modules 
Three Dual Beam antenna