Code acquisition device and method using two-step search process in DS-CDMA UWB modem
First Claim
1. A code acquisition device using a two-step search process in a Direct Sequence-Code Division Multiple Access (DS-CDMA) Ultra Wide Band (UWB) modem, the device comprising:
- an I/Q channel symbol generating unit for, in a first search process, generating a plurality (i) of nth I/Q channel symbols (YI,n(i), YQ,n(i)) consistent with a plurality (i) of code phases for a multi-path reception signal (r(t)) by using six spread code sequences, and in a second search process, generating a plurality of nth I/Q channel symbols (YI,n(i), YQ,n(i)) consistent with a plurality (i) of code phases for the multi-path reception signal (r(t)) by using a spread code having a maximal value among six spread codes acquired in the first search process;
a spread code selecting unit for, in the first search process, receiving the plurality of nth I/Q channel symbols (YI,n(i), YQ,n(i)) from the I/Q channel symbol generating unit to respectively combine the received channel symbols (YI,n(i), YQ,n(i)) at NNC1 times, and summing a respective combined result value (Zi) at each of the six spread codes to generate six symbol energies (Em, m=1,2, . . . ,
6) consistent with the six spread codes, and deciding the spread code having a maximal value among the six symbol energies (Em, m=1,2, . . . ,
6), as a spread code of a piconet coordinator;
an NNC2NS tap I/Q channel symbol matched filter unit having an Ns-length tap and for, in the second search process, receiving the plurality (i) of nth I/Q channel symbols (YI,n(i), YQ,n(i)) from the I/Q channel symbol generating unit to generate a result value (Sn,k(i)) through a predetermined arithmetic operation, and performing a noncoherent combining to the result value (Sn,k(i)) at NNC2 times to output an arbitrary result value (Xn(i));
a switching unit disposed between the I/Q channel symbol generating unit and the NNC2NS tap I/Q channel symbol matched filter unit, for changing an opened state of the first search process to a closed state of the second search process to connect the I/Q channel symbol generating unit with the NNC2NS tap I/Q channel symbol matched filter unit; and
a super frame and symbol boundary time deciding unit for deciding a super frame time and a symbol boundary time by using the output values (Xn(i)) of the plurality of NNC2NS tap I/Q channel symbol matched filters in the second search process.
1 Assignment
0 Petitions
Accused Products
Abstract
There is provided a code acquisition device and method using a two-step search process in a DS-CDMA UWB modem. The device includes: an I/Q channel symbol generating unit for, generating a plurality (i) of nth I/Q channel symbols in a first search process and generating a plurality of nth I/Q channel symbols in a second search process; a spread code selecting unit for receiving the plurality of nth I/Q channel symbols in the first search process; an NNC2NS tap I/Q channel symbol matched filter unit for, in the second search process, receiving the plurality (i) of nth I/Q channel symbols; a switching unit for changing to a closed state of the second search process; and a super frame and symbol boundary time deciding unit for deciding a super frame time and a symbol boundary time.
9 Citations
23 Claims
-
1. A code acquisition device using a two-step search process in a Direct Sequence-Code Division Multiple Access (DS-CDMA) Ultra Wide Band (UWB) modem, the device comprising:
-
an I/Q channel symbol generating unit for, in a first search process, generating a plurality (i) of nth I/Q channel symbols (YI,n(i), YQ,n(i)) consistent with a plurality (i) of code phases for a multi-path reception signal (r(t)) by using six spread code sequences, and in a second search process, generating a plurality of nth I/Q channel symbols (YI,n(i), YQ,n(i)) consistent with a plurality (i) of code phases for the multi-path reception signal (r(t)) by using a spread code having a maximal value among six spread codes acquired in the first search process; a spread code selecting unit for, in the first search process, receiving the plurality of nth I/Q channel symbols (YI,n(i), YQ,n(i)) from the I/Q channel symbol generating unit to respectively combine the received channel symbols (YI,n(i), YQ,n(i)) at NNC1 times, and summing a respective combined result value (Zi) at each of the six spread codes to generate six symbol energies (Em, m=1,2, . . . ,
6) consistent with the six spread codes, and deciding the spread code having a maximal value among the six symbol energies (Em, m=1,2, . . . ,
6), as a spread code of a piconet coordinator;an NNC2NS tap I/Q channel symbol matched filter unit having an Ns-length tap and for, in the second search process, receiving the plurality (i) of nth I/Q channel symbols (YI,n(i), YQ,n(i)) from the I/Q channel symbol generating unit to generate a result value (Sn,k(i)) through a predetermined arithmetic operation, and performing a noncoherent combining to the result value (Sn,k(i)) at NNC2 times to output an arbitrary result value (Xn(i)); a switching unit disposed between the I/Q channel symbol generating unit and the NNC2NS tap I/Q channel symbol matched filter unit, for changing an opened state of the first search process to a closed state of the second search process to connect the I/Q channel symbol generating unit with the NNC2NS tap I/Q channel symbol matched filter unit; and a super frame and symbol boundary time deciding unit for deciding a super frame time and a symbol boundary time by using the output values (Xn(i)) of the plurality of NNC2NS tap I/Q channel symbol matched filters in the second search process. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
-
16. A code acquisition method using a two-step search process in a Direct Sequence-Code Division Multiple Access (DS-CDMA) Ultra Wide Band (UWB) modem, the method comprising:
-
a step 10 of generating a plurality (i) of nth I/Q channel symbols (YI,n(i), YQ,n(i)) consistent with a plurality (i) of code phases for a multi-path reception signal (r(t)) by using six spread code sequences; a step 20 of respectively combining the plurality of nth I/Q channel symbols (YI,n(i), YQ,n(i)) at NNC1 times, and summing a respective combined result value (Zi) at each of six spread codes to generate six symbol energies (Em, m=1,2, . . . ,
6) consistent with the six spread codes, and deciding the spread code having a maximal value among the six symbol energies (Em, m=1,2, . . . ,
6), as a spread code of a piconet coordinator;a step 30 of generating a plurality (i) of nth I/Q channel symbols (YI,n(i), YQ,n(i)) consistent with a plurality (i) of code phases for the multi-path reception signal (r(t)) by using the spread code having the maximal value among the six spread codes; a step 40 of respectively performing an arithmetic operation for the plurality of nth I/Q channel symbols (Yl,n(i), YQ,n(i)) to generate a result value (Sn,k(i)), and respectively performing a noncoherent combining to the result value (Sn,k(i)) at NNC2 times to generate an arbitrary result value (Xn(i)); and a step 50 of deciding a super frame time and a symbol boundary time by using the generated result value (Xn(i)) obtained through the step 40. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
-
Specification