あらまし 次世代移動無線通信システムの実現に向けて,マルチホップバーチャルセルラネットワーク(VCN) が提案されている.筆者らは,直接拡散符号分割多元接続(DS-CDMA)VCN におけるマルチホップチャネル割当 てについて検討してきた.DS-CDMA では,異なる拡散符号を用いることによって VC 内で同一のチャネルを再利 用できるものの,隣接の無線ポート(WP)から処理利得で低減しきれないほどの大きな干渉を受ける場合がある. そこで,本論文では,VCN に直交周波数分割多元接続(OFDMA)を適用する.OFDMA では異なるサブキャリア を割当てることで隣接 WP からの干渉を避けることが可能である.本論文では,下りリンク2ホップ OFDMA VCN におけるチャネル構成法について検討している.ブロック型,等間隔型及び適応型チャネル構成法を用いたときの シャノンのチャネル容量を...

Non-orthogonal multiple access (NOMA) is a better technique than orthogonal (OMA), precisely frequency division (OFDMA) scheme, at the conceptual level for fifth-generation (5G) networks and beyond 5G (B5G) networks. We investigate potentials of schemes by comparing proposed NOMA scheme with traditional cooperative communication (CCNOMA) rather comparison between OMA only. To probe effectivenes...

The concept of scalability was introduced to the IEEE 802.16 WirelessMAN Orthogonal Frequency Division Multiplexing Access (OFDMA) mode by the 802.16 Task Group e (TGe). A scalable physical layer enables standard-based solutions to deliver optimum performance in channel bandwidths ranging from 1.25 MHz to 20 MHz with fixed subcarrier spacing for both fixed and portable/mobile usage models, whil...

We give a description of an OFDMA/OFDMA system, which is planned to combat the wireless channels for under 11GHz. This PHY proposal is submitted for consideration for the development of the TG3 PHY specification. Purpose This proposal should be used as the baseline for the PHY specification of the TG3. Notice This document has been prepared to assist IEEE 802.16. It is offered as a basis for di...

In next generation wireless networks such as 4GLTE and WiMax, the demand for high data rates, the scarcity of wireless resources and the time varying channel conditions has led to the adoption of more sophisticated and robust techniques in PHY such as orthogonal frequency division multiplexing (OFDM) and the corresponding access technique known as orthogonal frequency division multiplexing acce...

Cellular networks are confronted with an exponential increase in capacity requirements, due to the proliferation of high-end consumer devices (smartphones, tablets, e-readers) consuming ever increasing multimedia content. Clearly, availing of new spectrum (as with 4G allocations) is a necessary part of meeting this challenge, but so are improved network architectures that achieve enhanced spati...