Method and apparatus for detecting items of information transmitted according to the DS-CDMA principle in a receiver apparatus
First Claim
1. A method for detecting items of information transmitted according to the DS/CDMA principle in a receiver apparatus, the method comprising the steps of:
- simultaneously transmitting items of information in transmission signals dk(t) dependent on time t, over several individual connections k via a frequency channel;
forming reception signals e(t), received by the receiver apparatus by convolution of the transmission signals dk(t) with individual channel coefficients hk(t) representing transmission channels and with spread codes ck(t) of the individual connections k, wherein the spread codes ck(t) of at least two connections k are present and known in the receiver apparatus;
converting the reception e(t) signals in a base band;
separating items of information gk(t) related to the individual connections k to form a connection separation in a first step, wherein mutual interferences between the connections are taken into account, and wherein an expanded code matrix, with the spread codes ck(t) of at least two connections k and with additional indications, is used for separating the reception signals e(t), the code matrix being inverted and multiplied by the reception signals e(t); and
individually equalizing the items of information gk(t) related to the individual connections k in a second step which is subsequent to the first step of separating items of information.
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Abstract
A method and apparatus for detecting items of information transmitted according to the DS-CDMA principle in a receiver apparatus. According to the invention, the detection of items of information transmitted according to the DS-CDMA principle ensues in a receiver apparatus in that, given the presence of the spread codes of at least two connections, the items of information related to the individual connections are separated in a first step, and an individual equalization of the items of information related to the individual connections ensues thereupon. The invention can be used advantageously in mobile radiotelephone terminal apparatuses and base stations that operate according to the CDMA principle.
85 Citations
17 Claims
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1. A method for detecting items of information transmitted according to the DS/CDMA principle in a receiver apparatus, the method comprising the steps of:
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simultaneously transmitting items of information in transmission signals dk(t) dependent on time t, over several individual connections k via a frequency channel;
forming reception signals e(t), received by the receiver apparatus by convolution of the transmission signals dk(t) with individual channel coefficients hk(t) representing transmission channels and with spread codes ck(t) of the individual connections k, wherein the spread codes ck(t) of at least two connections k are present and known in the receiver apparatus;
converting the reception e(t) signals in a base band;
separating items of information gk(t) related to the individual connections k to form a connection separation in a first step, wherein mutual interferences between the connections are taken into account, and wherein an expanded code matrix, with the spread codes ck(t) of at least two connections k and with additional indications, is used for separating the reception signals e(t), the code matrix being inverted and multiplied by the reception signals e(t); and
individually equalizing the items of information gk(t) related to the individual connections k in a second step which is subsequent to the first step of separating items of information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A signal evaluation apparatus for detecting items of information of several individual connections k transmitted according to the DS-CDMA principle, the items being received simultaneously via a frequency channel and being dependent on a time t, wherein reception signals e(t) are represented in a base band by convolution of transmission signals dk(t) with individual channel coefficients hk(t) that represent transmission channels and with spread codes ck(t) of the individual connections k, the apparatus comprising:
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a memory apparatus for storing spread codes ck(t) of at least two connections k;
means for separating items of information gk(t) related to the individual connections k in a first step, wherein mutual interferences between the connections are taken into accounts wherein the means for separating provides an expansion of a code matrix with the spread codes ck(t) of at least two connections k by means of additional indications, the code matrix itself or a pseudo-inverse of the code matrix being stored in the memory apparatus;
means for individually equalizing the items of information gk(t) related to the individual connections k in a second step which is subsequent to the first step; and
means for detecting information that uses both the separated and equalized items of information of at least two connections k. - View Dependent Claims (14, 15, 16, 17)
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Specification