5G -NOMA & IBFD

5G TECHNOLOGY-NOMA & IBFD
ERICSSON WHITE PAPER
5G TECHNOLOGY- NOMA,
IBFD
5g Technology using Fidelity)
WHAT IS 5G?
The Next Generation Mobile Networks Alliance feels that 5G should be rolled out
by 2020 to meet business and consumer demands. In addition to providing simply
faster speeds, they predict that 5G networks also will need to meet new use cases
such as the Internet of Things (internet connected devices) as well as broadcast-
like services and lifeline communication in times of natural disaster. Although
updated standards that define capabilities beyond those defined in the current 4G
standards are under consideration, those new capabilities have been grouped under

the current ITU-T 4G standards. The U.S. Federal Communications
Commission (FCC) approved the spectrum for 5G, including the 28 Gigahertz, 37
GHz and 39 GHz bands, on July 14, 2016. 5G research and development also aims
at improved support of machine to machine communication, also known as
the Internet of things, aiming at lower cost, lower battery consumption and lower
latency than 4G equipment. To put it simply, the use cases for 4G networks has
expanded well beyond the initial scope of the standard. 5G is what you get when
you reset the standard/design to cope with the increase in scope.4G networks don’t
just support mobile devices anymore. IOT (Internet of Things) devices are
everywhere and the number of them is only going to increase. We’re seeing 4G
modems in smart watches, in CCTVs and even in doorbells. The problem is that
4G was never designed to support such a varied set of devices and as a result, the
4G ecosystem is fragmented and also congested.5G, as happened when the
transition to 4G happened, will consolidate all these standards under one roof and
accommodate for these expanding use cases. Essentially, 5G is bringing all
existing, fragmenting networking standards under one roof. “5G is an iterative and
progressive upgrade. “The initial transition to 5G wills, from a customer stand-
point, be a bit muddled, but that’s good, says Carson. Qualcomm for one is making
every effort to ensure that this transition is as seamless as possible in its initial
stages. If taking about more technical, 5G does support the 28 GHz band (mm
Wave as they call it), it will also support all existing networking frequencies. The
difference is that 5G is more efficient in every band as compared to 4G, resulting
in the vast improvements in performance that 5G will offer. To put the
improvements in perspective, 4G currently offers around 100-150Mbps speeds, 5G
can potentially offer over 1Gbps speeds at the same frequencies and even higher at
28GHz. Qualcomm even suggests that speeds up to 20Gbps (peak) can be achieved
at mm Wave bands.

5G REQUIREMENTS
By accounting for the majority of needs, the following set of 5G requirements is
gaining industry acceptance.
• 1-10Gbps connections to end points in the field (i.e. not theoretical
maximum)
• 1 millisecond end-to-end round trip delay - latency
• 1000x bandwidth per unit area
• 10-100x number of connected devices
• Perception of) 99.999% availability
• Perception of 100% coverage
• 90% reduction in network energy usage
• Up to ten year battery life for low power, machine-type devices
One of the key issues with the 5G requirements is that there are many different
interested parties involved, each wanting their own needs to be met by the new 5G
wireless system. This leads to the fact that not all the requirements form a coherent
list. No one technology is going to be able to meet all the needs together.
As a result of these widely varying requirements for 5G, many anticipate that the
new wireless system will be a umbrella that enables a number of different radio
access networks to operate together, each meeting a set of needs. As very high data
download and ultra-low latency requirements do not easily sit with low data rate
and long battery life times, it is likely that different radio access networks will be
needed for each of these requirements.
Accordingly it is likely that various combinations of a subset of the overall list of
requirements will be supported when and where it matters for the 5G wireless
system.

What is noma?
The key to NOMA, non-orthogonal multiple access is to have signals that possess
significant differences in power levels. It is then possible to totally isolate the high
level signal at the receiver and then cancel it out to leave only the low level signal.
In this way, NOMA exploits the path loss differences amongst users, although it
does need additional processing power in the receiver.
Looking at NOMA in a little more detail, non-orthogonality is intentionally
introduced either in time, frequency or code. Then as the signal is received DE
multiplexing is obtained as a result of the large power difference between the two
users. To extract the signal, successive interference cancellation is used within the
receiver. The channel gain consisting of elements including the path-loss and
received signal to noise ratio difference between users is translated into
multiplexing gains. Although power sharing reduces the power allocated to each
user, both users - those with high channel gains and those with low channel gains
benefit by being scheduled more frequently and by being assigned more
bandwidth. This means that NOMA enables system capacity and fairness of
allocations to be improved for all users. In addition to this NOMA, non-orthogonal
multiple access is able to support more connections than other systems and this
will become particularly useful in view of the massive projected increase in
connectivity for 5G materializes.
Motivations for noma
Orthogonal multiple access has been used during the past-FDMA, TDMA, CDMA,
OFDMA.Dilemma to realize a better trade-off between system throughput and user
fairness. A promising solution is to break orthogonality- PD-NOMA, SCMA,
PDMA, LPMA, and MUSA are based on NOMA.

NOMA is an intra-cell multi-user multiplexing scheme that utilizes an additional
new domain, i.e. power domain, which is not sufficiently utilized in previous 2G
(TDMA: Time Division Multiple Access), 3G (CDMA: Code Division Multiple
Access), and 4G (OFDMA: Orthogonal Frequency Domain Multiple Access)
systems. For downlink NOMA, non-orthogonality is intentionally introduced via
power-domain user multiplexing either in time/frequency/code domains. User de-
multiplexing is obtained through the allocation of large power difference between
paired users at the transmitter side and the application of successive interference
cancellation (SIC) at the receiver side. The channel gain (e.g., path-loss and
received SINR) difference among multiple users is translated into multiplexing
gains through superposition of the transmit signals of multiple users with large
channel gain (path loss) difference in the power-domain. Although power sharing
reduces the power allocated to each single user, both the users with high and low
channel gains benefit from being scheduled more often and being assigned more
bandwidth. As a result both system capacity and fairness can be improved.
Furthermore, NOMA can support more simultaneous connections, which is
suitable to address the challenges related to massive connectivity. In addition,
NOMA performs user multiplexing without relying on the knowledge of the
transmitter of the instantaneous channel state information (CSI) of each user. It is
expected, therefore, to achieve robust performance even in high mobility scenarios
and for backhauling for moving networks. Also, NOMA captures well the
evolution of processing capabilities of user devices generally following Moore’s
law, by relying on more advanced receiver processing schemes such as SIC. In the
same spirit, but for the purpose of inter-cell interference mitigation, discussions on
Network-assisted interference cancellation and suppression (NAICS) including
SIC are underway for LTE Release 12. In the future, NOMA can be introduced as
LTE/LTE-Advanced enhancements in lower frequency bands
Non-orthogonal
Multiple-Access
Towards 5G
With the deployment of commercial LTE networks worldwide, 4G is reaching
maturity. Looking forward to the future, the rapid growth in traffic data volume
and the number of connected mobile devices, and the emergence of diverse

application scenarios are still the main driving force to develop the next generation
communication system. In recent years, 5G has attracted extensive research and
development efforts from the wireless communication community. The
performance requirements of 5G systems have been firstly identified to adequately
support wireless communications in future scenarios. It is widely accepted that, in
comparison to LTE networks, 5G will be able to support 1000-fold gains in system
capacity, peak data rate of fiber-like 10 Gbps and 1 Gbps for low mobility and high
mobility, respectively, and at least 100 billion devices connections, ultra-low
energy consumption and latency. To fulfill these stringent requirements, the design
of 5G network architecture will be different from LTE, and the current OMA
schemes also need to be evolved. Several non-orthogonal MA schemes are under
investigation for 5G. Compared to OMA in LTE, the new MA enables
considerable performance improvements in system throughput and capacity of
connecting mobile devices. Moreover, the non-orthogonal design of MA provides
good backward compatibility with OFDMA and SC-FDMA In Release 13, 3GPP
has initiated a study on downlink multiuser superposition transmission (MUST) for
LTE, aiming at investigating multi-user non-orthogonal transmission, and the
design of advanced receivers. The concept of non-orthogonal multiple accesses is
that the same frequency resource, e.g., sub channels, RBs, can be shared by
multiple-user signals in the code or power domain, resulting in non-orthogonality
among user access. By relying on advanced receivers, multi-user detection and
successive interference cancellation (SIC) are applied for signal separation at the
receiver side . In this dissertation, we focus on a non-orthogonal MA scheme in the
power domain. The concept is proposed this scheme applies superposition coding
(SC) to superpose multiple UEs’ signals At the transmitter, and performs SIC at
the receiver to separate and decode multi-user signals. Throughout this
dissertation, we simply use NOMA” to denote this power-domain non-orthogonal
MA scheme. Figure 2 shows an illustration for single-cell OMA and NOMA in the
power (as well as frequency) domain. In OMA, each UE has exclusive access to
the radio resource, whereas each sub channel in NOMA can accommodate more
UEs. In OMA, the maximum number of UEs who can concurrently access the sub
channels is limited by the number of sub channels. Compared to OMA, the number
of the simultaneously multiplexed UEs in NOMA can be largely increased.
Dynamic switching between OMA and NOMA is considered in some works. In
practical scenarios, a hybrid scheme can be designed so that NOMA or OMA is
only performed when it enables better performance over the other scheme.

KEY IDEAS FOR NOMA (NON-ORTHOGONAL MULTIPLE
ACCESS)
 All the users are served at the same time, frequency and code
 Users with better channel conditions get less power
 Successive interference cancellation is used at the receivers

Why NOMA is an ideal MA solution of 5G
Consider the following two scenarios
–If one user only needs to be served with a low data rate, e.g. sensors.
•The use of OMA gives the sensor more than it needs
–If one user has a very poor channel condition
•The bandwidth allocated to this user via OMA is not used efficiently.
•The use of NOMA can accommodate the 5G requirements
–High system throughput
–Low latency
–Massive connectivity
The advent of advanced cell phones, tablet computers and other high-tech hand-
held devices
–MIMO offers excessive degrees of freedom to further improve the system
throughput of NOMA
Challenges for noma
The key feature of NOMA is to exploit the difference between users’ channel
conditions
–In scenarios with single-antenna nodes, channels are scalar and it is easy to order
the users based their channel conditions
–In MIMO, channels are in form of matrices/vectors, which makes difficult to
order users
•It is not clear how to design optimal precoding/detection strategies.
FUTURE DIRECTIONS
Different variants of NOMA

•New coding and modulation for NOMA
•Hybrid multiple access
•User pairing/clustering
•MIMO and cooperative NOMA
•Interplay between NOMA and cognitive radio
•Imperfect CSI and limited channel feedback
•Security provisioning in NOMA
•Cross-layer optimization
•Implementation issues of NOMA
•Emerging applications of NOMA
WHAT IS IBFD?
NEXT generation (5G) mobile networks target to sustain the evolution of mobile
communications in terms of Connectivity, throughput and spectral efficiency while
enhancing the user experience. To sustain this evolution, new Technologies are
being analyzed and developed. In-band full duplex (IBFD) wireless
communications is considered as a promising air interface technique for 5G as it
tackles key issues such as throughput, spectral efficiency, latency and connectivity.
The IBFD concept involves that a wireless terminal is allowed to transmit and
receive simultaneously in the same frequency band. The IBFD concept has been
successfully validated for both the network and the physical layer, and puts
additional requirements on the transceiver hardware. As 5G targets mass-market
adoption, commercially attractive IBFD transceivers should be:
- Compact and support dense system integration,
- Implementable in low-cost mass-production technology,
- Reconfigurable to support several communication schemes and backward
compatibility (e.g. time division duplexing (TDD) or frequency division duplexing
(FDD)),

- Compatible with in-system and/or legacy components (e.g. commercial off-the-
shelf components).
FULL-DUPLEX CONCEPT
MEETS 5G CHALLENGES
The rapid growth of mobile communication and massive advances in technology
are setting the ground for introducing 5G as the next step in the evolution of
mobile communication systems. The 5G challenges in respect to radio system
performance can:
- 1000 times higher mobile data volume per area,
- 10 to 100 times higher number of connected devices,
- 10 to 100 times higher user data rate,
- 10 times longer battery life for low power massive
Machine communication, and finally,
- 5 times reduced end-to-end latency.
To achieve these extremely challenging targets, radical changes in the network
architecture and significant developments in the air interface technologies are
needed. Demand for very wide transmission bandwidths calls for seeking new
spectrum in higher frequencies above 10 GHz. Support for higher bit rates and
high number of connected devices in frequency bands below 6 GHz calls for novel
solutions to improve spectrum efficiency and flexible use of spectral resources
IBFD OPERATION
IBFD operation sets high requirements on the transceiver implementation due to SI
phenomena (i.e., the transmit signal leaking into its own receiver), but when
successfully solved, it provides significant improvements to wireless systems
operation. Enabling wireless terminals to operate in full duplex transmission mode
offers the potential to double their spectral efficiency, i.e. the numbers of
transmitted bits per second per Hz. IBFD operation can also provide more
flexibility in spectrum usage. The same frequency resources can be used for one
directional or bi-directional transmission. IBFD operation can complement legacy
systems based on TDD or FDD. Beyond spectral efficiency and physical layer,
full-duplex concepts can be advantageously utilized in higher layers, such as at the

access layer. IBFD operation can reduce air interface delay due to simultaneous
reception of feedback information (control channels, signaling related to error
Correction protocol etc.) While transmitting data. IBFD capable terminals could
detect collisions while transmitting data and also resolves the ‘hidden node’
problem, both typical issues for contention based networks. Thus, IBFD operation
promise to enable various 5G mobile network targets.
IBFD ARCHITECTURE
The main idea of in-band full-duplex architectures is to use the same time and
spectral resources to exchange information. Contrary to current systems that
operate in half-duplex mode (unidirectional communication) or in out-of-band full-
duplex mode (time or frequency division multiple access schemes), this novel
approach enables a terminal to operate simultaneously over the same frequency
band, doubling the spectral efficiency of a system. When doing so, the problem of
self-interference arises. Self-interference consists of a perturbation of the
transmitted signal caused at the receiving antenna of the same terminal. Thus, a
terminal can cause interference to itself when transmitting a signal in the same
Frequency band of the signal it is also trying to listen to. Take a femto-cell of a
mobile system as an example: the power difference between these two signals is
about 40 dB, while the receiver noise floor is around 100 dBm. Imagine that a 0
dBm power signal is transmitted. The received power at a 15 cm away antenna is
about 40 dBm, hence if 60 dB of self-interference is removed, the signal is
theoretically decodable. Furthermore, it is intuitive that once a transmitted signal is
perfectly known at the transmitter, the self-interference can be totally suppressed.
However, several non-linarites in the radio frequency (RF) chain and errors in the
channel estimations may severely harm the filtering processes. Note that this value
is quite high and therefore the problem is not trivial. For those reasons, not so
many years ago, the telecommunication community thought that radio equipment
could not receive and transmit on the same frequency band. However, the demand
for faster data link streams and for reduced spectrum allocation encouraged the
study of in-band full-duplex communication in the last 4-5years, which makes it a
novel idea with a huge potential to integrate future technologies. As it will be
shown further, in order to suppress 60 dB of self-interference, in-band full-duplex
needs to cover a broad research area, involving telecommunications fields such as
antenna theory, propagation modeling, radio frequency circuits, information
theory, analogue signal processing, digital signal processing, networking etc.
Usually, the process of canceling the self-interference is divided into three
different stages or domains. Firstly, in terms of wireless propagation, there is the

possibility of combining techniques such as antenna directionality, cross-
polarization or transmit beamforming. In this case, the desired signal may also be
affected by these methods, which motivates the introduction of analog circuit
domain techniques.
CONCLUSION
This paper presented our NOMA & IBFD concept for FRA toward the 2020s
information society. Different from the current LTE radio access scheme, NOMA
superposes coding although its basic signal waveform could be based on OFDM or
DFT-spread OFDM as well as the LTE baseline. In our concept, NOMA adopts a
SIC receiver as a baseline receiver scheme for robust multiple access, with the
expected evolution of device processing capabilities in the future. Based on the
system-level evaluations, we demonstrated that the downlink NOMA with SIC
improves both the capacity and cell-edge user throughput performance irrespective
of the availability of the frequency-selective CQI at the BS transmitter side.
Furthermore, we discussed possible extensions of NOMA by applying jointly
multi-antenna/ site technologies with the proposed NOMA/MIMO scheme using
the SIC and IRC at the UE receivers to achieve a further capacity gain, e.g., a
three-fold gain in the spectrum efficiency representing a challenging target for
FRA(Future Radio Access). The in-band full duplex (IBFD) concept is a valid

candidate for resolving several challenges of next generation (5G) mobile
networks. The introduction of full-duplex in 5G however increases the design
requirements on the full-duplex radio transceivers. For commercial relevance and
Implementation in hand-held devices, these transceivers should support dense (co-
integration in a low-cost process) technology and be tunable to support
Communication schemes and backward compatibility.
REFERENCES
 3GPP TS36.300, Evolved Universal Terrestrial Radio Access (EUTRA) and
Evolved Universal Terrestrial Radio Access Network (EUTRAN) Overall
description
 Y. Kishiyama, A. Benjebbour, H. Ishii, and T. Nakamura, “Evolution
Concept and candidate technologies for future steps of LTE-A,”
 Goldsmith, Wireless Communications. Cambridge Univ. Press, 2005.
 X. Yang,, “Soft frequency reuse scheme for UTRAN LTE,” Huawei,
3GPP R1-050507, TSG-RAN1 #41, Athens, Greece, May 2005
 M. Al-Imari, P. Xiao, M. A. Imran, and R. Tafazolli, “Uplink no
orthogonal multiple access for 5g wireless networks,” in Proc. 2014 11th
International Symposium on Wireless Communications Systems, Aug.
2014, pp. 781–785
 https://www.ibfd.org/About-IBFD
 https://www.telekom.com/media/company
GLOSSARY
FRA-Future Radio Access
NOMA- Non-Orthogonal Multiple Access
IBFD-In Band Full Duplex
MIMO-Multiple Input Multiple Output
CQI-Channel Quality Index

5G -NOMA & IBFD

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