A VHDL Implementation of Orthogonal Interleavers for the IDMA Scheme
The IUP Journal of Telecommunications, Vol. I, No. 2, pp. 63-71, November 2009
Posted: 12 Dec 2009 Last revised: 23 Dec 2009
Date Written: December 10, 2009
Interleavers are referred to as integral parts for many systems such as Code Division Multiple Access (CDMA), Interleave Division Multiple Access (IDMA), and optical fiber communication. In case of CDMA, interleavers are used for coding gain, while for IDMA, they are employed for user separation. In case of optical fiber communication, interleavers are periodic optical filters that combine or separate a comb of dense wavelength division multiplexed signals. The challenge is to implement these interleavers at affordable decoding complexity and speed with the current fabrication technology. This paper first presents various orthogonal interleavers. It then performs the comparison on their performance and computational complexity. Next, it implements various interleavers on Field Programmable Gate Array (FPGA) using VHDL. After the comparison, it observes that the Tree-Based Interleaver (TBI) turns out to be the best compromise in terms of performance and complexity.
Keywords: Interleaver, Interleave Division Multiple Access (IDMA), Tree-Based Interleaver (TBI), Field Programmable Gate Array (FPGA)
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