Detection unit and method for the detection of data symbols
View Patent ↗A detection unit is disclosed for the detection of data symbols contained in a demodulated signal, whereby band spreading occurs transmit-side with the use of first sequences, whose first chips each assume one of two different first values. The detection unit comprises the following units: a) a sequence providing unit, which is designed to provide a group of second sequences with at least one second chip, whereby each second sequence is assigned to a first sequence and each second chip assumes a specific value of at least two different second values, which differ amount-wise from the first values, and whereby the group has at least one second sequence that has a higher level than the first sequences, b) a correlation unit which is connected to the sequence providing unit and is designed to calculate correlation results by correlating the demodulated signal with each second sequence of the group, and c) an evaluation unit which is connected to the correlation unit and is designed to derive the values of the data symbols by evaluating the correlation results. The invention further discloses a transmitting/receiving device and to an integrated circuit with such a detection unit and to a corresponding detection method.
1. A detection unit for the detection of data symbols in a demodulated signal, whereby band spreading occurs transmit-side with the use of first sequences whose first chips each assume one of two different first values, the detection unit comprising:
a sequence providing unit for providing a group of second sequences with at least one second chip, each second sequence being assigned to a first sequence and each second chip assuming a specific value of at least two different second values, which differ from the first values, the group having at least one second sequence that has a higher level than the first sequences;
a correlation unit connected to the sequence providing unit for calculating correlation results by correlating the demodulated signal with each second sequence of the group; and
an evaluation unit connected to the correlation unit for deriving values of the data symbols by evaluating the correlation results,
wherein each second chip assumes one specific value of at least two different second values, which each correspond in value to an integer positive power of two (2 1 , 2 2 , 2 3 ).
2. The detection unit according to claim 1 , wherein the value of the at least one second chip and/or its chip position within its second sequence are selected so that the error probability of detection due to the correlation decreases with this second sequence when the data symbols are transmitted over at least one typical transmission channel.
3. The detection unit according to claim 1 , wherein the number of second chips present in a second sequence is selected so that a number of second chips, exceeding this number does not cause a substantial decrease in the error probability of detection when the data symbols are transmitted over at least one typical transmission channel.
4. The detection unit according to claim 3 , wherein each second chip assumes one specific value of four different second values, which correspond in value to a 2× or 4× value of one of the first values.
5. The detection unit according to claim 3 , wherein each second chip assumes one specific value of two different second values, which correspond in value to 2× the value of one of the first values.
6. The detection unit according to claim 3 , wherein a sign of each second chip of a second sequence agrees with the sign of the positionally equivalent chip of the two-level sequence usable receiver-side, that is assigned to the first sequence to which this second sequence is assigned.
7. The detection unit according to claim 1 , wherein each second sequence has at least one third chip, which in each case assumes one of two different third values, which agree substantially in value with one of the first values.
8. The detection unit according to claim 7 , wherein in every second sequence, a total number of second and third chips agrees with the number of the chips present overall in this second sequence.
9. The detection unit according to claim 1 , wherein the sequence providing unit has exactly one memory, which stores exactly one of the second sequences.
10. The detection unit according to claim 9 , wherein the memory has a feedback shift register.
11. The detection unit according to claim 10 , wherein a component for clocking the feedback shift register and the sequence providing unit provides the second sequences at the outputs of the specific register cells of the feedback shift register.
12. A detection unit for the detection of data symbols in a demodulated signal, whereby band spreading occurs transmit-side with the use of first sequences whose first chips each assume one of two different first values, the detection unit comprising:
a sequence providing unit for providing a group of second sequences with at least one second chip, each second sequence being assigned to a first sequence and each second chip assuming a specific value of at least two different second values, which differ from the first values, the group having at least one second sequence that has a higher level than the first sequences;
a correlation unit connected to the sequence providing unit for calculating correlation results by correlating the demodulated signal with each second sequence of the group; and
an evaluation unit connected to the correlation unit for deriving values of the data symbols by evaluating the correlation results,
wherein the group, provided by the sequence providing unit comprises n≧1 second sequences, and wherein the correlation unit comprises:
n multiplication units, each connected to the sequence providing unit, for calculating n product signals by multiplying signal values of the demodulated signal by chip values in each case of one of the second sequences; and
n integration units, each connected to one of the multiplication units, for providing n correlation results by adding a number of signal values in each case of one of the n product signals.
13. The detection unit according to claim 12 , wherein the multiplication units have a component for sign reversal and a component for bit shifting.
14. A transmitting/receiving device for a data transmission system, comprising:
an antenna;
a transmitting unit, connected to the antenna, for transmitting data, whereby the transmitting unit performs band spreading with the use of first sequences whose first chips in each case assume one of two different first values;
a receiving unit, connected to the antenna, with a detection unit according to claim 1 ; and
a control unit, connected to the transmitting unit and the receiving unit, for controlling the transmitting unit and the receiving unit.
15. A method for detecting data symbols in a demodulated signal, whereby band spreading occurs transmit-side with the use-of first sequences whose first chips each assume one of two different first values, the method comprising:
providing a group of second sequences with at least one second chip, each second sequence being assigned to a first sequence and each second chip assuming a specific value of at least two different second values that differ in value from the first values, the group having at least one second sequence that has a higher level than the first sequences;
calculating the correlation results by correlating the demodulated signal with each second sequence of the group; and
deriving values of the data symbols by evaluating the correlation results,
wherein each second chip assumes one specific value of at least two different second values, which each correspond in value to an integer positive power of two (2 1 , 2 2 , 2 3 ).
16. The method according to claim 15 , wherein the value of the at least one second chip and/or its chip position within its second sequence are selected so that an error probability of detection due to the correlation decreases with the second sequence when the data symbols are transmitted over at least one transmission channel.
17. The method according to claim 15 , wherein the number of second chips present in a second sequence is selected so that a number of second chips exceeding this number does not cause a substantial decrease in the error probability of detection when the data symbols are transmitted over at least one transmission channel.
18. The method according to claim 15 , wherein each second chip assumes one specific value of four different second values, which correspond in value to the 2× or 4× value of one of the first values.
19. The method according to claim 15 , wherein each second chip assumes one specific value of two different second values, which correspond in value to a 2× value of one of the first values.
20. The method according to claim 15 , wherein a sign of each second chip of a second sequence agrees with a sign of a positionally equivalent chip of the two-level sequence usable receiver-side that is assigned to the first sequence to which this second sequence is assigned.
21. The method according to claim 15 , wherein each second sequence has at least one third chip, which in each case assumes one of two different third values, which agree in value with one of the first values.
22. The method according to claim 21 , wherein, in every second sequence, a total number of the second and third chips agrees with the number of the chips present overall in this second sequence.