Source: http://www.google.com/patents/US5533066?ie=ISO-8859-1
Timestamp: 2015-04-25 17:08:42
Document Index: 103327651

Matched Legal Cases: ['art 100', 'arts 101', 'arts 101', 'arts 101', 'arts 101', 'arts 102', 'art 300', 'art 300', 'arts 101', 'arts 101', 'arts 101', 'arts 101']

Patent US5533066 - Apparatus and method for estimating maximum likelihood sequence using ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA sampling phase calculating part calculates a complex cross-correlation function; of a part corresponding to a training sequence of an equalizer of each sequence with respect to individual sample value sequences i of a reception signal y(t) which are sampled in a plurality of different sampling phases...http://www.google.com/patents/US5533066?utm_source=gb-gplus-sharePatent US5533066 - Apparatus and method for estimating maximum likelihood sequence using optimum sampling phaseAdvanced Patent SearchPublication numberUS5533066 APublication typeGrantApplication numberUS 08/190,107Publication dateJul 2, 1996Filing dateFeb 2, 1994Priority dateJun 18, 1992Fee statusPaidAlso published asCA2113919A1, DE69332237D1, DE69332237T2, EP0602249A1, EP0602249A4, EP0602249B1, WO1993026106A1Publication number08190107, 190107, US 5533066 A, US 5533066A, US-A-5533066, US5533066 A, US5533066AInventorsNorio Yamaguchi, Haruhiro ShiinoOriginal AssigneeOki Electric Industry Co., Ltd.Export CitationBiBTeX, EndNote, RefManPatent Citations (8), Non-Patent Citations (6), Referenced by (32), Classifications (22), Legal Events (5) External Links: USPTO, USPTO Assignment, EspacenetApparatus and method for estimating maximum likelihood sequence using optimum sampling phase
In FIG. 6, one frame comprises six time slots (time segments) Slot 1�6. One or two of these time slots are assigned to one subscriber. Time slots Slot 1�6 respectively consist of a 28-bit training sequence SYNC for synchronization and training of an equalizer, a 12-bit control information sequence SACCH, a 12-bit adjacent channel identification sequence CDVCC, data part DATA of 260 bits in total, and a 12-bit reserved area RSVD.
This sampling phase calculating part 100 is provided with sampling parts 101-1�101-M which sample reception signal y(t) at the sampling phases of the above described sampling phase sequence τ and the symbol interval T, starting from the estimated leading time Et slot (k) of the time slot and obtain M number of sample value sequences i of the reception signal y(t). A maximum correlation index selector 103 is connected to the output sides of sampling parts 101-1�101-M through the correlation value calculators 102-1�102-M.
The correlation value calculators 102-1�102-M function to calculate complex cross-correlation values Ci (i=1, 2, . . . , M) from the sample value sequence i and corresponding training sequence .
The maximum correlation index selector 103 compares the absolute values of M complex cross-correlation values Ci which are calculated by the correlation value calculators 102-1�102-M and selects the sampling phase τ (Ik) where the absolute values are maximized. In addition, the maximum correlation index selector functions to output the index Ik of the selected sampling phase τ (Ik) as the index Ik of the sampling phase which is selected when the sampling phase for the time segment k is selected, and a sampling phase smoother 104 is connected to the output side thereof.
Reception signal y(t) is entered for each assigned time slot and sampled in the sampling parts 101-1�101-M for every finite section, according to the following equation when processing the kth assigned time slot, and entered into the correlation value calculators 102-1�102-M (ST501).
The correlation value calculators 102-1�102-M calculate the complex cross-correlation values Ci of the sample value sequences i and corresponding training sequence of reception signal y(t) according to the equation (8) given below and gives these values to the maximum correlation index selector 103 (ST502): ##EQU4## where * means that complex conjugation is used.
Thus, in this embodiment, the complex cross-correlation values Ci, for the training sequence of the equalizer of the parts {y (Et slot (k)+τ(1)+(n-1)T)} (n=1, 2, . . . , Nt) corresponding to the training sequence of the sample value sequences i of reception signal y(t), are calculated by the correlation value calculators 102-1�102-M with respect to each of a plurality of different sampling phases τ (i) when the reception signal is sampled with the above described sampling phases. Sampling phase τs is calculated from the sampling phases τ(i) where the complex cross-correlation values Ci are maximized by the maximum correlation index selector 103 and with the sampling phase smoother 104. Therefore the bit error rate (BER) can be improved to a greater degree than in the embodiments according to the prior art.
The sampling phase calculator 200 according to the second embodiment, as in the first embodiment, obtains complex cross-correlation values Ci (i=1, 2, . . . , M) from the reception signal y(t) and training sequence through the sampling parts 101-1�101-M and the correlation value calculating parts 102-1�102-M and gives these values to the maximum correlation index selector 103 (ST1301, ST1302).
In the third embodiment, the internal configuration of the sampling phase calculating part differs from that of the first embodiment. The following describes the configuration of the sampling phase calculating part 300, referring to FIG. 14(b). In FIG. 14(b), the sampling phase calculating part 300 is provided with sampling parts 101-1�101-M which sample the reception signal y (t) in each time segment k at respective sampling phases of the sampling phase sequence τ={τ(i)} (i=1, 2, . . . , M) and the symbol interval T as the symbol time, starting from the estimated leading time Et slot (k) of the time slot (time segment) k and obtain M number of different sample value sequences i ={yin} (i=1, 2, . . . , M; n=1, 2 . . . . , Nt) of the reception signal. The maximum correlation sampling phase selector 302 is connected to the output sides of sampling parts 101-1�101-M through the correlation value calculators 102-1�102-M.
The correlation value calculators 102-1�102-M function to calculate for each time segment k complex cross-correlation values Ci (i=1, 2, . . . , M) of the sample value sequences i and the training sequence SYNC ={φn} (N=1, 2, . . . , Nt).
The maximum correlation sampling phase selector 302 functions for each time segment k: (1) to compare the absolute values of M number of complex cross-correlation values Ci calculated by the correlation value calculators 102-1�102-M to determine which of the absolute values is maximum, (2) to select a sampling phase τ sel (k) for the time segment k corresponding to the value Ci whose absolute value is maximum, and (3) to output the selected sampling phase. The sampling phase smoother 301 is connected to the output side of the maximum correlation sampling phase selector 302.
The reception signal is entered during each assigned time slot (time segment) and sampled by the sampling parts 101-1�101-M according to equation (7) when the kth assigned slot is processed, then entered respectively into the correlation value calculators 102-1�102-M (ST1501).
Each of correlation value calculators 102-1�102-M calculates complex cross-correlation values Ci of the sample value sequences i and corresponding training sequence of reception signal y(t), according to equation (8) and gives the values obtained to the maximum correlation sampling phase selector 302 (ST1502).
The maximum correlation sampling phase selector 302 selects a sampling phase τ sel (k) where the absolute values of M number of cross-correlation values Ci are maximized and gives the selected sampling phase to the sampling phase smoother as the sampling phase τ sel (k) when the kth sampling phase is selected (ST1504). The sampling phase smoother 301 outputs the sampling phases τs obtained according to the following equations (18)�(23) (ST1504�ST1507). ##EQU8## where, Ws: Shift coefficient
by the sampling parts 101-1�101-M and the correlation value calculators 102-1�102-M and give these functions to the maximum correlation sampling phase selector 302 (ST1701, ST1702).
When the maximum correlation sampling phase selector 302 selects a sampling phase τ sel (k) where the absolute values of correlation values Ci are maximized and gives this selected sampling phase to the sampling phase smoother 401 as the sampling phase τ sel (k) which is selected in the kth selection of the sampling phase (ST1703), the sampling phase smoother 401 outputs the sampling phase τs obtained according to the following equations (24)�(30) in the kth calculation (for the time segment k) of the sampling phase (ST1704�ST1707). ##EQU9##
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