| Presentation | 2009-06-26 Spreading Code Sequences Appropriate for Maximum Likelihood Detection in MC-CDMA Akira Wakamiya, Kenichi Higuchi, |
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| Abstract(in Japanese) | (See Japanese page) |
| Abstract(in English) | This paper investigates the spreading code sequences appropriate for the multicarrier code division multiple access (MC-CDMA) assuming the maximum likelihood detection (MLD) at the receiver. The conventional Walsh code sequence-based spreading code does not allow for exploitation of full diversity using MLD due to the zero product codeword distance. We propose two spreading codes named a rotated Walsh code which is generated by applying phase rotation to the conventional Walsh code sequence and quadrature amplitude modulation (QAM) code whose constellation after spreading and code-multiplexing takes QAM-like shape. By designing the spreading code so that the minimum product codeword distance becomes larger than zero, these proposed codes achieve full frequency diversity. Consequently, When the spreading factor is 2, 4 and 8, the proposed spreading code can reduce the received signal energy per bit-to-noise spectrum density ratio (E_b/N_0) for the average BER of 10^<-3> by approximately 5.5dB, 3.5dB and 2.0dB comparing to the conventional Walsh code sequence-based spreading code, respectively, when QPSK data modulation and MLD at receiver are assumed. Furthermore, when the 16QAM data modulation is used, the proposed spreading code can reduce the received E_b/N_0 by approximately 5.0dB and 7.0dB for the spreading factor of 2 and 4, respectively. |
| Keyword(in Japanese) | (See Japanese page) |
| Keyword(in English) | MC-CDMA / Spreading code / Maximum likelihood detection / Diversity |
| Paper # | RCS2009-48 |
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| Committee | RCS |
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| Conference Date | 2009/6/18(1days) |
| Place (in Japanese) | (See Japanese page) |
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| Registration To | Radio Communication Systems (RCS) |
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| Language | JPN |
| Title (in Japanese) | (See Japanese page) |
| Sub Title (in Japanese) | (See Japanese page) |
| Title (in English) | Spreading Code Sequences Appropriate for Maximum Likelihood Detection in MC-CDMA |
| Sub Title (in English) | |
| Keyword(1) | MC-CDMA |
| Keyword(2) | Spreading code |
| Keyword(3) | Maximum likelihood detection |
| Keyword(4) | Diversity |
| 1st Author's Name | Akira Wakamiya |
| 1st Author's Affiliation | Department of Electrical Engineering, Graduate School of Science and Technology Tokyo University of Science() |
| 2nd Author's Name | Kenichi Higuchi |
| 2nd Author's Affiliation | Department of Electrical Engineering, Graduate School of Science and Technology Tokyo University of Science |
| Date | 2009-06-26 |
| Paper # | RCS2009-48 |
| Volume (vol) | vol.109 |
| Number (no) | 105 |
| Page | pp.pp.- |
| #Pages | 6 |
| Date of Issue | |