To push 5G technology boundaries,
we have been investing in building advanced prototypes
of upcoming 5G deployments and designs.
This demonstration utilizes our end-to-end 5G
NR Standalone test network in San Diego,
operating in the 3.5 GHz spectrum
with 100 MHz bandwidth.
The multi-cell system supports gNodeBs
with advanced multi-user massive MIMO, along with a 5G
NextGen Core and 5G NR mobile test devices
based on the Qualcomm Snapdragon 5G modem-RF system.
Last year, we showcased our system simulation
of a subband full-duplex system,
which provides the ability for a gNodeB to transmit
and receive at same time in the same spectrum band.
Since then, we have upgraded our OTA test network
to get a step closer
to full duplex operation in TDD spectrum.
This year, our network can support subband half-duplex,
which enables dynamic TDD operation and allows
for more flexible service multiplexing
as well as improved latency and coverage.
Here is our OTA network,
we see two gNodeBs and two devices.
Device 1 on the left is driving
uplink-heavy bursty traffic,
sitting on the cell edge of gNodeB1,
while Device 2 on the right
is driving downlink-heavy bursty traffic,
served by gNodeB2.
In the baseline scenario,
we have a time-division duplex system
that is typically deployed
with a fixed half-duplex slot structure across the network.
TDD operation requires all cells to operate with the
uplink/downlink pattern to prevent cross-link interference.
For example, we are using a slot structure that has
3 consecutive downlink slots
followed by an uplink slot.
Device 1 is utilizing a small portion
of 100 MHz bandwidth
due to power limitation, being on the cell-edge.
Its performance is further limited
by the 25% uplink duty cycle.
In the case of subband half-duplex, we dedicated a portion
of the bandwidth for downlink and another for uplink.
This allows the cells to use different slot structures
to adapt to traffic needs and reduces switching latency.
gNodeB1 adopts the "DUDU" slot structure,
delivering more uplink opportunities,
whereas gNodeB2 maintains the "DDDU" format
to serve its downlink-heavy user.
In slot 1 and 3,
both gNodeBs are transmitting on downlink
with no cross-link interference.
This is also true in slot 4 for uplink.
In the second slot,
gNodeB1 is receiving on uplink while gNodeB2
is transmitting on downlink.
The downlink-to-uplink interference is mitigated
through subband operation, where uplink
and downlink transmissions use different subband
of the channel,
minimizing the leakage of downlink subband transmission
to adjacent uplink subband reception.
Device 1 uplink packet latency and perceived throughput are
significantly improved due to increased uplink duty cycle,
while Device 2 still gets 75% duty cycle from gNodeB2.
Downlink user perceived throughput and latency
are mostly not impacted.
Subband half-duplex enables flexible deployments
that can adapt to varying traffic requirements,
allowing more efficient service multiplexing.
We will continue to make great strides
towards subband full duplex,
so stay tuned!
To expand 5G to new devices, services, and deployments,
we have been working
on pioneering future 5G technologies in
3GPP Release 16 and beyond.
This year, we are showcasing how 5G is evolving
to support new capabilities beyond data communication.
This demonstration provides an overview
of our work in the different fronts of 5G positioning.
Earlier this year at MWC Shanghai,
we showcased our collaboration
with ZTE to prototype 5G single-cell positioning
based on roundtrip time and angle of arrival.
The roundtrip time measurement provides an estimation
of the device's distance from the gNodeB,
and the angle of arrival derives the elevation
and azimuth direction of the device.
Combining both, the 5G system can determine the location
of the device.
The OTA network operates in China Mobile's
2.6 GHz band over with 100 MHz channel.
The gNodeB is mounted on top of a 6-story building,
with ZTE's massive MIMO base station with 64 Tx/Rx antennas.
The location server is designed
and operated by Qualcomm Technologies,
and the device is based on the Snapdragon modem-RF system.
From the walk test,
we see this simple setup delivering 80th percentile horizontal
and vertical accuracy of 2.1 meters
and 1.2 meters, respectively.
It's important to note
that this is the raw accuracy using only the 5G system
for positioning,
without the aids
of temporal processing, GNSS or other sensor data.
Adding these elements can further improve accuracy.
Since then, we have expanded this OTA prototype to
support a multi-cell implementation
with 5 gNodeBs.
From this expanded effort,
we have also tested 5G positioning capability
for non-line-of-sight and indoor scenarios.
From the results, we have shown
that this implementation can provide robust location
positioning services in most practical deployment scenarios.
Moreover, we have also prototyped 5G positioning in our
own end-to-end 5G wide-area test network in San Diego.
In addition to 5G NR positioning based
on Rel-16, we have also adopted machine learning
techniques and sensor fusion to further
enhance positioning performance and efficiency.
These field-testing results demonstrated
that high precision 5G positioning could play
an important role to complement GNSS.
Furthermore, Qualcomm's wireless AI technology
is shown to be synergistic to 5G positioning.
We are taking large strides
towards realizing 5G positioning in the real-world,
and we continue to work
with industry leaders in demonstrating 5G's capabilities.
You can find the three demos I have mentioned here,
and please stay tuned for future updates.