This paper focuses on a CDMA radio link with a 'turbo-decoding' (TD) scheme. The radio link concept is based on the requirements for third generation mobile radio communications. The performance of the CDMA link is evaluated for ATM service scenarios with 32 kbit/s low-delay speech and 64 kbit/s data transmission. For this reason, Monte-Carlo simulations based on measured mobile radio impulse responses are performed. As a reference to which TD can be compared, a one-dimensional convolutional code with soft-decision Viterbi decoding (VD) is alternatively used. The simulation results show that a single coding scheme with TD may be advantageously applied for data as well as for low-delay speech services.

Introduces construction methods for synthesizing new classes of perfect sequences and arrays. Time discrete sequences and arrays are perfect, if their periodic autocorrelation function sidelobes are zero. The construction of perfect three-level and three-phase sequences is performed in two steps. In the first step, a maximal length shift-register sequence with elements in GF(q) is built for a length of g/sup m//spl minus/1, where q is a prime power and m is a positive integer. In the second step, a sequence is constructed by mapping the elements of the shift-register sequence to 1, b/sub 1/ or b/sub 2/. Two real numbers b/sub 1/ and b/sub 2/ are determined such that the sequence becomes perfect and has high energy efficiency. The phase values for complex numbers b/sub 1/ and b/sub 2/ with magnitude 1 are given for perfect three-phase sequences. It is shown that the phase values of b/sub 1/ and b/sub 2/ tend for growing lengths to 2/spl pi//3 and 4/spl pi//3. A different similar synthesizing method starts with Legendre sequences. The construction of perfect three-level and three-phase arrays is performed by several methods, which make use of the new respective sequences.>

Perfect arrays are defined by having zero out-of-phase autocorrelation sidelobes. Such arrays find many applications, e.g. in two-dimensional synchronization techniques. With a known construction method, it is shown that perfect phase arrays can be obtained for every size. However, the phase alphabets of these constructed phase arrays increase by the size of the arrays. With further construction schemes the phase alphabet of perfect phase arrays can be reduced for particular sizes. Classes of perfect phase arrays are obtained whose phase alphabet does not increase with the size of the arrays.>

Perfect sequences and arrays have periodic autocorrelation functions whose out-of-phase values are zero. Time-discrete N-phase sequences and arrays have complex elements of magnitude one, and one of (2 pi /N)n, 0>

New complex sequences with elements are proposed that have constant absolute values of 1. The periodic autocorrelation functions of these sequences are shown to be two-level. The sequences are generated by three consecutive mapping processes. The number of sequences of fixed length is determined, which is larger than the number of binary sequences. For cryptographical reasons, the large linear span of the sequences is of great interest. The linear span of the new sequences is examined and is proven to be larger than the linear span of complex m-sequences, if the parameters of the mapping processes are appropriately chosen. The formula for generating the sequences is generalized to enlarge the linear span of sequences.>

An iterative method for increasing the energy efficiencies of given Huffman sequences is introduced. The iteration scheme works by varying the roots and the radius of the Z-transformation of Huffman sequences. The algorithm allows the intensity of the variations of the possible root positions to be changed. In this way the energy efficiencies of long real and complex valued Huffman sequences can be optimized. The algorithm has been applied to known Huffman sequences. The resulting efficiencies of real and complex valued Huffman sequences are given up to 100 elements.>

Binary sequences and arrays with the highest possible PACF merit factor, which is a measure for a low PACF (periodic autocorrelation function) sidelobe energy, are investigated. It is shown that some of these sequences and arrays can be obtained with known construction schemes; others are found by methods of complete computer search. The resulting PACF merit factors are given in a table up to 39 elements. A transformation from pseudonoise sequences into biphase sequences is introduced for the construction of a new class of biphase sequences and arrays with zero autocorrelation sidelobes.>

Signals of two or more dimensions with ideal impulse-like periodic autocorrelation functions are used in higher-dimensional signal processing or in radar systems. Four synthesizing methods for perfect ternary arrays are presented. Based on known perfect binary and ternary sequences and arrays, many new perfect ternary arrays with increasing number of elements are constructed. New strong conditions for the existence of perfect arrays are developed. By combining these conditions with an advanced computer search, new ternary arrays are found. These new ternary arrays can be used as starting arrays to construct additional perfect ternary sequences and arrays.>

Perfect binary arrays can exist for numbers of elements that are even square numbers. Two-dimensional (2-D) perfect binary arrays are 4, 16, 36, and 144 elements are known. Perfect binary arrays with 64 elements can be constructed for three or more dimensions. Here, two-dimensional binary arrays with 64 elements are examined. The results of computer search for symmetric binary arrays with 64 elements are presented in the form of two 2-D perfect binary arrays with sizes 8*8 and 4*16. Applications of these perfect binary arrays are in 2-D synchronization, time-frequency coding, and coding loudspeaker fields.>

Existence conditions and recursive construction procedures for sets of periodic complementary binary sequences are given. Relationships to sets of aperiodic complementary binary sequences and to perfect binary arrays, whose two-dimensional periodic autocorrelation function is a delta function, are noted. The connections of periodic complementary binary sequences and difference families are given. Sets of periodic complementary binary sequences, which result from computer search, are presented. A diagram showing what is currently known about the existence of periodic complementary binary sequences with P>

A survey is presented of different methods for constructing binary arrays with constant PACF sidelobes. For each method the sizes, numbers of elements, and PACF sidelobe level of the resulting binary arrays are specified. Binary arrays with vanishing sidelobes are considered in detail. Properties of the discrete Fourier transform of arrays with constant PACF sidelobes are examined. These properties are shown to be of great importance in acoustics.>