Name
Title | ||
|---|---|---|
Rotated Walsh-Hadamard Spreading with Robust Channel Estimation for a Coded MC-CDMA System. |
Abstract | ||
|---|---|---|
We investigate rotated Walsh-Hadamard spreading matrices for a broadband MC-CDMA system with robust channel estimation in the synchronous downlink. The similarities between rotated spreading and signal space diversity are outlined. In a multiuser MC-CDMA system, possible performance improvements are based on the chosen detector, the channel code, and its Hamming distance. By applying rotated spreading in comparison to a standard Walsh-Hadamard spreading code, a higher throughput can be achieved. As combining the channel code and the spreading code forms a concatenated code, the overall minimum Hamming distance of the concatenated code increases. This asymptotically results in an improvement of the bit error rate for high signal-to-noise ratio. Higher convolutional channel code rates are mostly generated by puncturing good low-rate channel codes. The overall Hamming distance decreases significantly for the punctured channel codes. Higher channel code rates are favorable for MC-CDMA, as MC-CDMA utilizes diversity more efficiently compared to pure OFDMA. The application of rotated spreading in an MC-CDMA system allows exploiting diversity even further.We demonstrate that the rotated spreading gain is still present for a robust pilot-aided channel estimator. In a well-designed system, rotated spreading extends the performance by using a maximum likelihood detector with robust channel estimation at the receiver by about 1 dB. |
Year | DOI | Venue |
|---|---|---|
2004 | 10.1155/S1687147204406021 | EURASIP J. Wireless Comm. and Networking |
Keywords | Field | DocType |
punctured channel code,concatenated code increase,channel code,multicarrier,and phrases: code division multiaccess,mc-cdma system,fading channels,higher channel code rate,convolutional channel code rate,concate- nated channel coding.,concatenated code,robust channel estimation,robust pilot-aided channel estimator,good low-rate channel code,walsh-hadamard spreading sequences,rotated walsh-hadamard,fading channel,channel coding | Forward error correction,Binary symmetric channel,Concatenated error correction code,Repetition code,Telecommunications,Constant-weight code,Computer science,Algorithm,Real-time computing,Hamming distance,Linear code,Decoding methods | Journal |
Volume | Issue | ISSN |
2004 | 1 | 1687-1499 |
Citations | PageRank | References |
8 | 0.81 | 8 |
Authors | ||
5 | ||
Name | Order | Citations | PageRank |
|---|---|---|---|
| Ronald Raulefs | 1 | 196 | 19.66 |
| armin dammann | 2 | 212 | 36.06 |
| Stephan Sand | 3 | 77 | 17.33 |
| Stefan Kaiser | 4 | 154 | 26.54 |
| Gunther Auer | 5 | 1136 | 76.60 |