A Hybrid Multiple Access Scheme Delivering Reliability Information
نویسندگان
چکیده
A multiple access scheme referred to as IDMA (interleave-division multiple-access) is combined with OCDMA (CDMA with orthogonal spreading sequences) to obtain a new hybrid multiple access scheme referred to as OCDMA/IDMA. The new scheme is shown to outperform IDMA for a sufficiently large number of users and asymptotically approaches single user performance even for a bit load of as high as 3.75. A link-adaptive transmission scheme based on the reliability information at the decoder output is presented. The feasability of the soft decoder output values as reliability information is examined for IDMA and OCDMA/IDMA. It is shown that IDMA and OCDMA/IDMA are suitable to deliver correct reliability information. This property makes the OCDMA/IDMA scheme very attractive for the proposed link-adaptive system, especially with the need for high throughputs in combination with high adaptivity.
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