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Summary: 1984 IEEE TRANSACTIONS ON INFORMATION THEORY, VOL. 45, NO. 6, SEPTEMBER 1999
Optimal Sequences and Sum Capacity
of Synchronous CDMA Systems
Pramod Viswanath, Student Member, IEEE, and Venkat Anantharam, Fellow, IEEE
Abstract--The sum capacity of a multiuser synchronous CDMA
system is completely characterized in the general case of asym-
metric user power constraints--this solves the open problem
posed in [7] which had solved the equal power constraint case.
We identify the signature sequences with real components that
achieve sum capacity and indicate a simple recursive algorithm
to construct them.
Index Terms--Capacity region, CDMA, optimal signature se-
quences, sum capacity.
I. INTRODUCTION
AN important multiple-access technique in wireless net-
works and other common channel communication sys-
tems is Code-Division Multiple Access (CDMA). Each user
shares the entire bandwidth with all the other users and
is distinguished from the others by its signature sequence
or code. Each user spreads its information on the common
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