• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.5 s.347
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• pp.17-23
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• 2006

In this paper, Adjacent Channel Power Ratio (ACPR) of wireless Orthogonal Frequency Division Multiplexed (OFDM) system interconnected with Radio over Fiber (RoF) link is analyzed for broadband convergence network applications. Unlike previous results, ACPR of the total link, which is involved with Radio Frequency (RF) amplifier as well as ROF link, at 5.8 GHz in IEEE 802.11a environment is simulated and compared at both system ends.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.10
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• pp.4618-4639
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• 2018

One of the most innovative paradigms for the next-generation of wireless cellular networks is the cloud-radio access networks (C-RANs). In C-RANs, base station functions are distributed between the remote radio heads (RHHs) and base band unit (BBU) pool, and a communication link is defined between them which is referred as the fronthaul. This leveraging link is expected to reduce the CAPEX (capital expenditure) and OPEX (operating expense) of envisioned cellular architectures as well as improves the spectral and energy efficiencies, provides the high scalability, and efficient mobility management capabilities. The fronthaul link carries the baseband signals between the RRHs and BBU pool using the digital radio over fiber (RoF) based common public radio interface (CPRI). CPRI based optical links imposed stringent synchronization, latency and throughput requirements on the fronthaul. As a result, fronthaul becomes a hinder in commercial deployments of C-RANs and is seen as one of a major bottleneck for backbone networks. The optimization of fronthaul is still a challenging issue and requires further exploration at industrial and academic levels. This paper comprehensively summarized the current challenges and requirements of fronthaul networks, and discusses the recently proposed system architectures, virtualization techniques, key transport technologies and compression schemes to carry the time-sensitive traffic in fronthaul networks.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.2
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• pp.3-9
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• 2016

In this paper, we propose a Radio over Fiber system for small cell applications and for mobile fronthaul networks supporting cloud-radio access networks(RAN). We built a system with a downlink employing orthogonal frequency division multiplexing (OFDM) techniques and an uplink using single carrier-frequency multiple access(SC-FDMA). System parameters are evaluated for various subcarrier modulations and the results of link performance measurements are analyzed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.5A
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• pp.509-516
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• 2008

The Fast Handover in Hierarchical Mobile IPv6(F-HMIPv6) scheme provides a seamless handover in mobile IP networks effectively. However, there is a problem that the mobile node can lose its connectivity to the previous access router because of a sudden degradation of the link quality during fast handover procedure. Additionally, in many cases, the mobile node does not have enough time to exchange messages during the fast handover procedure, especially in case of movement with high speed during handover. In this paper, we propose a modification to F-HMIPv6 that significantly reduces the time to exchange messages during fast handover procedure and thereby increases the probability which the F-HMIPv6 can perform the fast handover in predictive mode.