Comment on Cochannel intersymbol interference in quadrature modulation systems

A question has arisen concerning the similarity of a paper published by M.I. Celebiler and G.M. Coupe (ibid., vol. COM- 26, pp. 257-267, Feb. 1978.) and the above-named one published by the authors (ibid., vol. COM-29, pp. 285-297, Mar. 1981). The first paper considers the problems of cochannel and intersymbol interferences in CPSK systems. In 1981 paper the results of Celebiler and Coupe were extended to the case of quadrature modulated systems. Because the 1981 paper is an extension of Celebiler and Coupe, it naturally makes heavy use of their results. It was an unfortunate oversight on our part that the appropriate amount of credit was not given to Celebiler and Coupe. We did reference the workbut because the method used was very similar, it would have been appropriate to cite it at several points in our paper and perhaps draw more from their results, rather than repeating their procedure. We would like to apologize to Celebiler and Coupe for this oversight and acknowledge the usefulness of their results in interference analyses.