This document discusses LTE refarming of 1800 MHz spectrum from 2G to 4G networks. It describes what LTE and refarming are, why operators want to refarm 1800 MHz for LTE, different types of refarming approaches, advantages of refarming to increase capacity, and technical considerations for refarming part or all of 1800 MHz spectrum for LTE use while mitigating interference. The key benefits of refarming include increasing network capacity to support rising data demand in a cost-effective way without needing new spectrum auctions.

1. Central-1 Region
Prepared By
Muhammad Imran(ZTE RAN Engineer)
(imran.eng02@gmail.com)
LTE Refarming TP Projects

2. Contents
1-Introduction.
2-Why Refarm the 1800 MHz Spectrum for LTE Use?
3-Frequency Bands for LTE Refarming.
4-Types Of Refarming
5-Advantages
6-conclusion

3. Introduction
What is LTE?
LTE is recognized as the future mobile technology in all regions of the world, offering
high enough data speed and spectrum efficiency to satisfy the rising data traffic needs
of demanding end users.
What is LTE Refarming ?
Refarming is the term used for the process governing the repurposing of frequency
band that have historically been allocated for 2G mobile services. For new generation
of mobile technologies, Including both 3rd .(Using 3G Technology) and 4th
Generation.(Using LTE Technology).

4. Continue
Now a days the actual issue is refarming of the existing
frequency range for LTE deployment.
The most common band is 900/1800 MHz, which is usually
licensed for the GSM networks.
It is known that LTE network core can be easily integrated
with the existing GSM infrastructure.
The convergent base stations have already known, they
can operate with GSM/LTE/WCDMA simultaneously.

5. Why Refarm the 1800 MHz Spectrum for LTE Use?
Mobile data services have developed very fast in recent
years.
The number of mobile data services is doubling every year.
Increasing the capacity to accommodate data services has
become the top priority of mobile operators.
Compared with 3G technology, LTE has high spectrum use,
high peak data rates, and low latency.

6. Continue
However, there is not much spectrum available for LTE, and
the price for LTE spectrum is very high.
Many operators are therefore considering the potential of
existing frequencies.
In most countries, 1800 MHz is used for GSM, and it has a lot
of free frequency bands for other mobile technologies.
Therefore, it is possible to use these free 1800 MHz bands
for LTE

7. Frequency Bands for LTE Refarming.

8. Types Of Refarming
1. One-off Refarming
2. Interim Refarming

9. One-off Refarming
One-off Refarming is relocate part of the 1800 band to 4G
Network once for all.
Such type of refarming is preferable for operators with a
wide spectral band.

10. Interim Refarming
This solution is suitable for operators whose spectra
resources are limited.
Some operators still carry a high percentage of mobile
phone users.
We can do a spectrum refarming only in part to the use of
LTE.
The interim refarming is a flexible system that proposes to
reallocate GSM Spectrum as a function of lower GSM Traffic.

11. Continue
For the interim refarming to modes of assigning frequencies
are available which are
1. Sandwich Frequency allocation
2. Edge Frequency allocation

12. Channel Bandwidth Range for LTE Refarming
1 2 3 4 5 6
1.4MHz 3MHz 5MHz 10MHz 15MHz 20MHz
LTE physical layer supports any bandwidth
from 1.4 MHz to 20 MHz .
Current LTE specification supports a subset of 6
different system Channel bandwidths.
All UEs must support the maximum bandwidth
of 20 MHz

13. LTE1800 Refarming Solutions
Solution A: Refarm the entire GSM1800 spectrum for LTE use.
Operators only need to swap their existing terminals from 1800 MHz to 900 MHz . The
spectrum refarming is quite straightforward.
Solution B: Refarm part of the GSM1800 spectrum for LTE use. LTE1800 is located
between GSM1800 frequency bands.
Operators have to consider interference between LTE and GSM at the frequency edge.
Solution C: Refarm part of the GSM1800 spectrum for LTE use. LTE1800 is located on
one side of GSM1800 frequency band.
Operators have to consider interference between LTE and GSM at the frequency edge
as well as interference between LTE and another neighboring frequency band.

14. LTE1800 Refarming Interference
When LTE1800 is located between GSM1800 frequency bands
and the LTE1800 bandwidth is 1.4 MHz or 3 MHz, a guard band
of 0.2 MHz is needed. If the LTE1800 bandwidth is more than 3
MHz, no guard band is needed.
When LTE1800 is located on one side of GSM1800 frequency
band and the LTE bandwidth is 1.4 MHz or 3 MHz, a guard band
of 0.2 MHz is also needed, and interference between LTE and
its neighboring frequency band has to be considered.

15. Adventages
 Refarming is a cost-effective way to increase capacity for
GSM/UMTS/LTE without the need to bid for new
spectrum.
 Refarming is not limited to GSM, since UMTS spectrum
can also be refarmed to increase LTE capacity. Another
interesting benefit for operators is that lower frequencies
(usually allocated to GSM networks) provide much better
coverage.

16. Conclusion
The GSM1800 frequency band is becoming an important part of LTE development
In term of Spectrum usage, the benefits of spectrum refarming for improved quality of
services and coverage are well understood.
However these benefits need to b weighed against the challenges faced by each mobile
operators during planning and execution of spectrum refarming activity.
.

17. Thank you