#### DMCA

## A Multi-levelled OFDM-CDMA Modem Using Complete Complementary Codes

### Citations

431 |
Overview of multicarrier CDMA
- Hara, Prasad
- 1997
(Show Context)
Citation Context .... The implementation of the fast Fourier transform (FFT) allows for high spectral efficiency, due to the minimum frequency spacing in carriers and for a low complexity transmitter and receiver design =-=[3]-=-. Various multi-carrier schemes which use the combination of CDMA and OFDM have been proposed, these can be mainly categorised according to the direction of spreading. The spreading of the data is eit... |

81 |
Broadband CDMA techniques
- Adachi, Garg, et al.
(Show Context)
Citation Context ...and OFDM have been proposed, these can be mainly categorised according to the direction of spreading. The spreading of the data is either done in the time domain or frequency domain or even both [2], =-=[4]-=-. An important factor in the overall performance of a CDMA multi-carrier type modulation scheme is the perfect autocorrelation and zero cross-correlation property of the spreading codes. Due to non-id... |

28 |
A multi-carrier CDMA architecture based on orthogonal complementary codes for new generation of wideband wireless communications
- Chen, Yeh, et al.
- 2001
(Show Context)
Citation Context ...ion property of the spreading codes. Due to non-ideal spreading codes used in current standardised CDMA systems, such as those used in existing 2-3G systems, problems of self-interference are evident =-=[5]-=-, [6]. These existing problems in current systems such as slow transmission rate, low capacity, and complex system implementation are caused by the imperfect spreading codes implemented [7]. For examp... |

27 |
Multicarrier DSCDMA: A multiple access scheme for ubiquitous broadband wireless comm.”,
- Yang, Hanzo
- 2003
(Show Context)
Citation Context ...lity of spectrum becomes a serious problem [1]. Meanwhile, code division multiple access (CDMA) has proven its spectral efficiency through flexible frequency reuse and multiple access techniques [1], =-=[2]-=-. The combination of multiple access techniques like CDMA and OFDM, demonstrated increased spectral efficiency, flexibility in radio resource allocation and anti-multipath and antiinterference feature... |

7 |
Design of an MC-CDMA system that uses complete complementary orthogonal spreading codes
- Magaña, Rajatasereekul, et al.
- 2007
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Citation Context ...CDMA-based systems (i.e., IS-95, cdma2000, and W-CDMA), and even multi-carrier adaptations, have a spreading efficiency of 1/L information bits per chip per link (where L is the sequence length) [5], =-=[9]-=-, whereas the novel modulation technique can transmit at 2 information bits per chip per link or channel user. II. MULTI-DIMENSIONAL MODEM BUILDING BLOCK The novel modulation technique makes use of a ... |

5 |
Performance Analysis for OFDMCDMA With Joint Frequency-Time Spreading
- Zheng, Zeng, et al.
- 2005
(Show Context)
Citation Context ...elective fading environments. However, it is limited by its spectral efficiency and with the growing demand of digital audio/video broadcasting, the availability of spectrum becomes a serious problem =-=[1]-=-. Meanwhile, code division multiple access (CDMA) has proven its spectral efficiency through flexible frequency reuse and multiple access techniques [1], [2]. The combination of multiple access techni... |

2 |
Design of next-generation CDMA using orthogonal complementary codes and offset stacked spreading
- Chen, Hank, et al.
(Show Context)
Citation Context ...re evident [5], [6]. These existing problems in current systems such as slow transmission rate, low capacity, and complex system implementation are caused by the imperfect spreading codes implemented =-=[7]-=-. For example, according to [8], the WalshHadamard sequences in the IS-95 standard and the OVSF codes in WCDMA standards made it impossible to ensure symmetric data throughput at the very beginning of... |

2 | An algebraic approach to generate super-set of perfect complementary codes for interference-free CDMA - Chen, Chu, et al. - 2007 |

2 | Performance of a Quasi-Synchronous Four-Dimensional Super-Orthogonal WCDMA Modulator for Next Generation Wireless Applications
- Linde, Staphorst, et al.
- 2007
(Show Context)
Citation Context ...s implemented with rotated complete complementary codes to offer MAI-free and MI-free operation, due to the perfect autocorrelation and zero cross-correlation properties of the codes. It was shown by =-=[10]-=-, [11] that a 4-dimensional modem building block (without the newly implemented CRCC codes) has data throughput rates equivalent to that of a 16-ary quadrature amplitude modulated (16-QAM) WCDMA modul... |

2 |
Performance of a complete complementary code-based spread-time CDMA system in a fading channel
- Lu, Dubey
- 2008
(Show Context)
Citation Context ... gain (PG) of the codes can then be defined by L. √ L, where L is the length of every element code sequence [5], [9]. The autocorrelation and cross-correlation of the code can be expressed as follows =-=[15]-=-: φxx(j) = L 2 −1∑ n=−L2 √ L∑ i=1 a (x) n,ia (x) n+j,i = { L √ L, j = 0 0, j 6= 0 (3) φxy(j) = L 2 −1∑ n=−L2 √ L∑ i=1 a (x) n,ia (y) n+j,i = 0 (4) where φxx is the autocorrelation function (3) of set ... |

2 |
On Next Generation CDMA Technologies: The REAL Approach for Perfect Orthogonal
- Chen, Chu, et al.
(Show Context)
Citation Context ...ifts between the sequences, and n is the nth element of each code sequence [15]. A. Complete Complementary Code generation There are various ways in constructing complete complementary codes. In [8], =-=[16]-=- an algebraic method is used to generate super complementary code sets called the real environment adapted linearisation (REAL) approach. The REAL approach generates interference-free CDMA code sets w... |

1 |
N-Shift Cross-Orthogonal Sequences and Complete Complementary Codes
- Han, Suehiro, et al.
- 2007
(Show Context)
Citation Context ...roperty of the spreading codes. Due to non-ideal spreading codes used in current standardised CDMA systems, such as those used in existing 2-3G systems, problems of self-interference are evident [5], =-=[6]-=-. These existing problems in current systems such as slow transmission rate, low capacity, and complex system implementation are caused by the imperfect spreading codes implemented [7]. For example, a... |

1 |
A Multi-dimensional super-orthogonal modulation alternative to M-QAM WCDMA for next generation wireless applications
- Linde
- 2007
(Show Context)
Citation Context ...emented with rotated complete complementary codes to offer MAI-free and MI-free operation, due to the perfect autocorrelation and zero cross-correlation properties of the codes. It was shown by [10], =-=[11]-=- that a 4-dimensional modem building block (without the newly implemented CRCC codes) has data throughput rates equivalent to that of a 16-ary quadrature amplitude modulated (16-QAM) WCDMA modulation ... |

1 |
Performance of sparse graph codes on a four-dimensional CDMA system
- Vlok, Linde
- 2007
(Show Context)
Citation Context ...hed filter correlation-type receiver for a 4-dimensional modem. The receiver is depicted without the periodic cross correlation receiver structure needed when using the rotated codes (CRCC). In [10], =-=[12]-=- it was shown that the data throughput rate of one basic 4-dimensional building block is twice that of a direct sequence spread spectrum (DSSS) QPSK modulation system, yielding a spectral efficiency o... |

1 |
Complete Complementary Orthogonal (CCO) Code-Based CDMA Using Natural Mapping
- Magaña, Rajatasereekul
- 2006
(Show Context)
Citation Context ... between spreading codes allow the receiver to separate user signals, whereas low autocorrelation values aid in filtering out multiple received signals, which are delayed due to multipath propagation =-=[13]-=-. If a CDMA system is not multiple access interference (MAI)-free and multipath interference (MI)-free, due to nonideal cross-correlation and autocorrelation properties respectively, then the capacity... |

1 |
The REAL Approach to Generate Orthogonal Complementary Codes for Next Generation
- Chen
- 2006
(Show Context)
Citation Context ...apacity of the overall system can merely achieve capacity equal to approximately one-third to a half of its processing gain, which is currently seen in available CDMA-based 2-3G wireless systems [8], =-=[14]-=-. The proposed system is based on complete complementary code spreading, which can achieve interference-free performance and high capacity due to their inherent ideal auto/crosscorrelation properties.... |