Page 261 - ITU Kaleidoscope 2016

Session 3 - Spectral efficiency in wireless networks

S3.1 Space division multiplexing technology: next generation optical communication strategy.*
Kazuhide Nakajima; Takashi Matsui; Kotaro Saito; Taiji Sakamoto; Noriyuki Araki (NTT
Corporation, Japan)
Space division multiplexing (SDM) is expected to be a key technology both for dealing with the
future capacity crunch facing traditional single-mode fibre (SMF) and for realizing a sustainable
optical network that can accommodate the various data streams originating from, for example,
future 5G communication, the Internet of things (IoT), and machine to machine (M2M) networks.
This paper describes the potential of SDM as regards optical fibre and cable technology. We focus
on the potential of multi-core fibre (MCF), and investigate the reality of MCF based SDM optical
wiring as the first example of an SDM application taking the latest research and development into
consideration. Finally, we show that MCF based SDM optical fibre cable will be a promising
technology for next generation optical networks, and the key technology behind MCF based SDM

optical wiring is ready for discussion as the near future standard.
S3.2 Resource allocation for device-to-device communications in multi-cell LTE-advanced wireless
networks with C-RAN architecture.*
Sajjad Mehri Alamouti; Ahmad R. Sharafat (Tarbiat Modares University, Iran)

Device-to-device (D2D) communications underlaying LTE-Advanced wireless networks reuse
cellular frequency spectrum to establish direct links between users without traversing base stations
or the cellular network. In this paradigm, there is a need to optimally allocate resources with a view
to maximizing the utility, e.g., the total throughput, and mitigating the interference caused by
sharing the same spectrum between cellular users (CUs) and D2D pairs. This paper proposes a
scheme for optimally allocating transmit power levels and channels to maximize the total number
of active D2D pairs and reused channels while minimizing the aggregate transmit power pertaining
to CUs and D2D pairs. We consider a multi-cell scenario in which the transmitter and the receiver
of each D2D pair can be in the same cell or in two different cells, and each user can simultaneously
transmit over multiple reused channels. The optimization is done via a centralized baseband
processing in the cloud radio access network (C-RAN) architecture. Simulations show that via our
proposed scheme, more users (both cellular users and D2D pairs) can simultaneously communicate
and the total system throughput is also significantly increased.

S3.3 PAPR reduction in SC-FDMA via a novel combined pulse-shaping scheme.
Naser Ahmadi Moghaddam; Ahmad R. Sharafat (Tarbiat Modares University, Iran)

Peak-to-average-power-ratio (PAPR) is an important parameter that affects the cost of end-user
devices in next generation wireless networks. When PAPR is high, the end-user power amplifier’s
dynamic range should also be high, resulting in costly power amplifiers. Single-carrier frequency-
division-multiple-access (SC-FDMA) is used as the air-interface in LTE-Advanced, and this paper
proposes a novel and efficient technique for PAPR reduction via pulse shaping for interleaved-
FDMA (IFDMA) subcarrier mapping in SC-FDMA. By way of simulations, we show that PAPR
can be reduced by 2.11 dB for our novel pulse shaping compared to raised cosine (RC) pulse
shaping with QPSK modulation.

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