LTE/4G networks business plans involve capex spend on radio access infrastructure to meet business objectives ito customer offerings ito bandwidth, data rates, bulk data and QoS. Assigning some Capex to CPE equipment with outdoor antennas can reduce Capex significantly for same capacity and considerably better reliability and QOS

1. Your logo
here
Emergence of powerful business models
for fixed wireless data
Dr Andre Fourie
CEO, Poynting Antennas

2. Overview
• Revenue generating capacity of LTE
base station limited by:
– Spectrum
– Efficient use thereof
• E.g., spectral cost of delivering:
– 1 Mbit/s for 1 minute
– 10 Mbit/s for 1 minute
• Must maximise use of spectrum

3. Effect of outdoor antennas
Data rate attained (up/down) (Mbit/s)
LTE device Using
internal
antennas
LPDA-
A0092 (dual
polarised)
XPOL-
A0001
XPOL-
A0002
Huawei
B593
2.47/1.72 11.2/8.95 10.5/6.83 9.83/8.36
Huawei
E3276
2.19/0.75 11.8/4.56 10.3/4.47 12/7.56

4. Effect of outdoor antennas
• 4-5 times improvement in download
speeds
• Commensurate increase in revenue
generation capability

5. Why are outdoor antennas
better?
• Higher gain antenna
• Ability to filter out noise (cf omni)
• Outdoor vs indoor environment

6. Characteristics of indoor
environment
• Rayleigh fading

7. Characteristics of outdoor
environment (with LOS)
Additive white Gaussian noise

8. Characteristics of general
outdoor environment
• Characteristics lie somewhere
between Rayleigh and AWGN fading
• Ricean distribution
• K-factor; defining ratio between
predominant signal and multipath
components

9. Comparison

10. Comparison
• Assume use 64QM 5/6 outdoors
• SNRoutdoor = 18 dB
• SNRindoor = 34 dB
• => move antenna outdoors gains 16
dB signal improvement
• Gain of outdoor antenna improves
further

11. FCC: using outdoor antennas
• Spectral efficiency improved more
than 75%

12. FCC: quote
• Figures quoted by the FCC indicate
that if a CPE with an omni antenna
experiences a data rate of 3 Mbit/s,
then that same user will average 9
Mbit/s by converting to an outdoor
directional antenna.

13. Our experience reiterated
Data rate attained (up/down) (Mbit/s)
LTE device Using
internal
antennas
LPDA-A0092
(dual
polarised)
XPOL-
A0001
XPOL-
A0002
Huawei
B593
2.47/1.72 11.2/8.95 10.5/6.83 9.83/8.36
Huawei
E3276
2.19/0.75 11.8/4.56 10.3/4.47 12/7.56

14. What have we established
• Established that outdoor directional
antennas have a large impact on LTE
performance
• Reasons for why this is the case have
been given
• For business purposes; need to
establish the system capacity of an
LTE cell

15. Practical LTE capacity
• Advertised that 20 MHz LTE link
achieve 300 Mbit/s
• Vodacom recently claimed 380 Mbit/s
on 2x20 MHz LTE
• Is this practically what one expects?

16. WiMAX carrier capacity :
Korowajczuk
Carrier overhead Percentage
Guard bands 18
Pilot DL and UL 25
Cyclic prefix 13
TDD partition 5
TDD gap 3
OFDMA preamble and mapping 10
Total for support 72
Available for data 28

17. Additional overhead
Data overhead Minimum
(%)
Maximum
(%)
Coding 17 50
MAC overhead 3 5
HARQ 10 15
Total 30 70
Available for data 20 8

18. Summary: WiMAX capacity
• Only 8% to 20% of the carrier
capacity is available for the actual
data to be transmitted in WiMAX.
• A similar situation is to be found for
LTE

19. LTE capacity (no overhead)
NO OVERHEAD Normal cyclic
prefix
Channel bandwidth (MHz) 10 20
Transmission bandwidth (MHz) 9 18
Bandwidth efficiency (%) 90 90
FFT size 1024 2048
Number of used sub-carriers 600 1200
Number of sub-carrier groups 50 100
Number of resource blocks / frame 1000 2000
Number of resource elements / frame 84 168
Number of resource elements / second 8.4 16.8
Minimum throughput with no overhead and
QPSK (Mbit/s)
16.8 33.6
Maximum throughput with no overhead and
64QAM (Mbit/s)
50.4 100.8

20. Comment on published LTE
performance
• With 20 MHz spectrum achieve 100.8
Mbit/s with no MIMO
• Assume 4x4 MIMO 403.2
Mbit/s
• Vodacom achieved 380 Mbit/s but the
data contained no overhead and no
error correction data

21. Include overhead
INCLUDING OVERHEAD Normal cyclic prefix
Channel bandwidth (MHz) 10 20
Number of sub-carrier groups 50 100
Total resource elements / frame (thousand) 84 168
Reference signals RE / frame (thousand) 2.0 4.0
PSS RE / frame (thousand) 4.2 8.4
SSS RE / frame (thousand) 4.2 8.4
PBCH RE / frame (thousand) 4.0 8.0
PDCCH RE / frame (thousand) 19.0 38.0
PDSCH RE / frame (thousand) 50.6 101.2
Channel coding overhead (turbo code at 1/3) % 66 66
Channel coding overhead (turbo code at 2/3) % 33 33
Percentage of RE available for data (worst case) 20 20
Percentage of RE available for data (best case) 40 40
Minimum throughput (QPSK) with overhead (Mbit/s) 3.44 6.88
Maximum throughput (64QAM) with overhead (Mbit/s) 20.34 40.68

22. Include overhead and
inefficiencies
INCLUDING OVERHEAD AND
INEFFICIENCIES
Normal cyclic
prefix
Channel bandwidth (MHz) 10 20
RB allocation inefficiency (%) 80 80
RB sub-utilisation (%) 78 78
ARQ and H_ARQ (%) 88 88
Minimum throughput (QPSK) with
overhead and inefficiency (Mbit/s)
1.89 3.78
Maximum throughput (64QAM) with
overhead and inefficiency (Mbit/s)
11.17 22.34

23. Include MIMO
UPLINK INCLUDING OVERHEAD AND
INEFFICIENCIES AND MIMO
Normal cyclic
prefix
Channel bandwidth (MHz) 10 20
Minimum throughput (QPSK) with
overhead and inefficiency (Mbit/s)
1.89 3.78
Maximum throughput (64QAM) with
overhead and inefficiency (Mbit/s)
21.2 42.5

24. Summary of LTE performance
• 380 Mbit/s is possible as long as no
overhead or error correction is
required – one user and a highly
specialised application
• The total capacity is closer to 40
Mbit/s assuming excellent signal
quality to all users! In reality capacity
will be less than this!

25. The business case for outdoor
antennas
• We have established:
Parameter Value
LTE billable spectrum 4-42.5 Mbit/s
Improvement in data speeds due to
external directional antennas rather than
internal omni antennas
3-5 times

26. A simplified user distribution

27. The financial effect of outdoor
antennas

28. Conclusion
• The use of outdoor direction antennas
improves the spectral use of the base
station
• Improving the spectral use is
financially beneficial