Hi. My name is Martha Zemede. I am an applications engineer here with Agilent Technologies. One
of the test challenges engineers have today is in demodulating LTE Advanced inter-band
carrier aggregation signals. In this short video, I will show you how Agilent addresses
this test challenge with our signal generation and analysis solutions. Carrier aggregation
is one of the major features of LTE Advanced that allows two or LTE carriers to be aggregated
to create wide transmission bandwidth of up to 100 MHz in order to achieve the LTE Advanced
target peak data rates of up to one GB per second.
By definition, these aggregated carriers – also called component carriers – can be contiguous
or non-contiguous and both within a single frequency band – also known as intra-band
– or multiple frequency bands – also known as inter-band carrier aggregation. Inter-band
carrier aggregation is the most realistic deployment scenario since spectrum allocation
for operators is often scattered across multiple frequency bands. It is also the most challenging,
especially for user equipment, since it requires multiple transceivers being operated simultaneously
to cover the multiple bands.
One of the major physical layer test challenges is demodulating these component carriers simultaneously
since the frequency band separation and the inter-band scenario is wider than the IF bandwidth
of any commercially available signal analyzer. What you will learn in this video is how Agilent
addresses this test challenge with the 89600 VSA software along with dual X-Series signal
analyzers or the N7109A multi-channel signal analyzer. Our setup today includes two MXG
signal generators. I have the top MXG generating two component carriers at 800 MHz frequency
band and I have the second MXG transmitting three component carriers at 2100 MHz frequency
band.
I have two synchronized MXA signal analyzers, each one of them connected to the right frequency
of the MXGs, and I have a single instance of the 89600 VSA software that is doing the
capture from the two MXAs and it is doing simultaneous analysis on all of the five component
carriers from the two frequency bands. Even though the demonstration today is focused
on the downlink, the same features and capabilities are also available for uplink analysis. On
the 89600 VSA software, I have selected LTE Advanced application and under the demod properties,
I select the number of component carriers to be five. I then specify the correct input
and the correct frequency offsets for each component carrier.
So as you can see, two component carriers are at 800 MHz using input number one, which
is the top MXA, and I have three component carriers at 2100 MHz using input number two,
which is the bottom MXA. The settings for each component carrier can be specified independently
by selecting a component carrier on the common tab and then specify the settings on the other
tabs, such as the signal bandwidth. The demodulator then performs simultaneous but separate demodulation
of each component carrier and measurement results are provided for each component carrier.
The bottom two traces show the spectrum for the two frequency bands and the top five traces
show demodulator results of component carriers zero through four.
And for each component carrier, I am overlaying three trace windows: the frame summary trace
showing all the active channels along with their EVM, power and modulation formats; a
constellation diagram; and a detected allocations time trace that shows the resource allocations
in the two-dimensional grid with frequency on the vertical axis and time on the horizontal
axis. All of these traces are color-coded according to the channel type and the frame
summary trace shows all the channels and their corresponding colors. As you can see, the
different component carriers have users with different modulation formats and some of them
only occupy a portion of the available resource whereas some of them, like component carrier
two, occupies all the available resources.
I also want to point out there are more than 40 available trace data for each component
carrier including various EMV traces and summary tables. What I am showing here is just three
out of the more than 40 available traces. As I have just shown, Agilent with its industry’s
most comprehensive LTE Advanced solution can help you test your most challenging LTE Advanced
designs. For more information on Agilent’s LTE Advanced test solutions, please visit
our website. Thank you for your time.