Pilot signals for synchronization and/or channel estimation

• US 6,987,746 B1
• Filed: 03/14/2000
• Issued: 01/17/2006
• Est. Priority Date: 03/15/1999
• Status: Expired due to Fees

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Information & Communications Ltd. (LG Corporation)
• Inventors: Song, Young-Joon
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): LEE, CHI HO A
• Application Number:
  US09/525,447
• Time in Patent Office: 2,135 Days
• Field of Search: 370/335, 370/342, 370/500, 370/509, 370/512, 370/514, 370/503, 370/515, 370/502, 370/497, 375/354, 375/356, 375/364, 375/365, 375/367, 375/368, 375149-150, 375/142, 375/242, 375/360
• US Class Current: 370/335
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04B 7/264 for data rate control
• CPC Class Codes: H04W 56/0085 detecting a given structure in the signal

Abstract

The frame words of the preferred embodiment are especially suitable for frame synchronization and/or channel estimation. By adding the autocorrelation and cross-correlation functions of frame words, double maximum values equal in magnitude and opposite polarity at zero and middle shifts are obtained. This property can be used to slot-by-slot, double-check frame synchronization timing, single frame synchronization and/or channel estimation and allows reduction of the synchronization search time. Further, the present invention allows a simpler construction of a correlator circuit for a receiver. A frame synchronization apparatus and method using an optimal pilot pattern is used in a wide band code division multiple Access (W-CDMA) next generation mobile communication system. This method includes the steps of storing column sequences demodulated and inputted by slots, in a frame unit, in detecting frame synchronization for upward and downward link channels; converting the stored column sequences according to a pattern characteristic related to each sequence by using the pattern characteristic obtained from the relation between the column sequences; adding the converted column sequences by slots; and performing a correlation process of the added result to a previously designated code column.

Claims

1. A method for an apparatus receiving a pilot pattern, comprising:

storing pilot pattern sequences demodulated and/or inputted by slots of a frame for at least one of channel estimation or frame synchronization for at least one of uplink channel or downlink channel, wherein the pilot pattern sequences have a relation based on one or both of the following;

$\begin{array}{cc}\underset{i=1}{\overset{\mathrm{\alpha <br><br>}}{\sum <br><br>}}<br><br>\text{\hspace{1em}<br><br>}<br><br>R_i<br><br>\left(\mathrm{\tau <br><br>}\right)=\{\begin{array}{c}\mathrm{\alpha <br><br>}·<br><br>15,\mathrm{\tau <br><br>}=0\\ -\mathrm{\alpha <br><br>},\mathrm{\tau <br><br>}\ne <br><br>0\end{array},\mathrm{\alpha <br><br>}=1,2,3,\mathrm{\dots <br><br>}<br><br>\text{\hspace{1em}<br><br>},8& \left(1\right)\end{array}$

where ∝

=1, 2, 3, . . . , 8 and R_i(τ

) is representative of a first correlation function of the each pilot pattern sequence;

$\begin{array}{cc}\underset{i=1}{\overset{\mathrm{\alpha <br><br>}/2}{\sum <br><br>}}<br><br>\text{\hspace{1em}<br><br>}<br><br>\left(R_{2<br><br>i-1,2<br><br>i}<br><br>\left(\mathrm{\tau <br><br>}\right)+R_{2<br><br>i,2<br><br>i-1}<br><br>\left(\mathrm{\tau <br><br>}+1\right)\right)=\{\begin{array}{c}-\mathrm{\alpha <br><br>}·<br><br>15,\mathrm{\tau <br><br>}=7\\ \mathrm{\alpha <br><br>},\mathrm{\tau <br><br>}\ne <br><br>7\end{array},\mathrm{\alpha <br><br>}=2,4,6,8& \left(2\right)\end{array}$

where ∝

=2, 4, 6, 8 and R<sub>2i−

1, 2i</sub> (τ

) and R<sub>2i, 2i−

1</sub> are representative of a second correlation function between a pair of pilot pattern sequences, and i≧

1.

3. The method of claim 1, wherein 2≦

i≦

8.

5. The method of claim 1, further comprising converting the stored column sequences according to a pattern characteristic related to each sequence by using the pattern characteristic obtained from the relation between the column sequences;

adding the converted column sequences by slots; and

performing a correlation process of the added result to a previously designed code column.

7. The method of claim 1, wherein the first correlation function is an auto-correlation function and the second correlation function is a cross-correlation function.

2. An apparatus receiving a pilot pattern comprising:

a memory mapping and/or addressing block for storing pilot pattern sequences inputted and/or demodulated by slots, wherein the pilot pattern sequences have a relation based on one or both of the following;

$\begin{array}{cc}\underset{i=1}{\overset{\mathrm{\alpha <br><br>}}{\sum <br><br>}}<br><br>\text{\hspace{1em}<br><br>}<br><br>R_i<br><br>\left(\mathrm{\tau <br><br>}\right)=\{\begin{array}{c}\mathrm{\alpha <br><br>}·<br><br>15,\mathrm{\tau <br><br>}=0\\ -\mathrm{\alpha <br><br>},\mathrm{\tau <br><br>}\ne <br><br>0\end{array},\mathrm{\alpha <br><br>}=1,2,3,\mathrm{\dots <br><br>}<br><br>\text{\hspace{1em}<br><br>},8& \left(1\right)\end{array}$

where ∝

=1, 2, 3, . . . , 8 and R_i(τ

) is representative of a first correlation function of the each pilot pattern sequence and i≧

1$\begin{array}{cc}\underset{i=1}{\overset{\mathrm{\alpha <br><br>}/2}{\sum <br><br>}}<br><br>\text{\hspace{1em}<br><br>}<br><br>\left(R_{2<br><br>i-1,2<br><br>i}<br><br>\left(\mathrm{\tau <br><br>}\right)+R_{2<br><br>i,2<br><br>i-1}<br><br>\left(\mathrm{\tau <br><br>}+1\right)\right)=\{\begin{array}{c}-\mathrm{\alpha <br><br>}·<br><br>15,\mathrm{\tau <br><br>}=7\\ \mathrm{\alpha <br><br>},\mathrm{\tau <br><br>}\ne <br><br>7\end{array},\mathrm{\alpha <br><br>}=2,4,6,8& \left(2\right)\end{array}$

where ∝

=2, 4, 6, 8 and R<sub>2i−

1, 2i</sub>(τ

) and R<sub>2i, 2i−

1</sub> are representative of a second correlation function between a pair of pilot pattern sequences and i≧

1.

4. The apparatus of claim 2, wherein 2≦

i≦

8.

6. The apparatus of claim 2, wherein the implementing means comprises:

an adder for adding the converted outputs from the memory mapping/addressing block; and

a correlator for performing a correlation process of the added result to a previously designated code column.

8. The apparatus of claim 2, wherein the first correlation function is an auto-correlation function and the second correlation function is a cross-correlation function.

9. A method for an apparatus receiving a pilot pattern, comprising:

storing pilot pattern sequences demodulated and/or inputted by slots of a frame for at least one of channel estimation or frame synchronization for at least one of uplink or downlink channels, wherein the pilot pattern sequences have a relation based on one or both of the following;

$\begin{array}{cc}{R}_i<br><br>\left(\mathrm{\tau <br><br>}\right)=\{\begin{array}{c}15,\mathrm{\tau <br><br>}=0\\ -1,\mathrm{\tau <br><br>}\ne <br><br>0\end{array},i=1,2,\mathrm{\dots <br><br>}<br><br>\text{\hspace{1em}<br><br>},8& \left(1\right)\end{array}$

where R_i(τ

) is the auto-correlation function of the pilot pattern sequence, $\begin{array}{cc}{R}_{i,j}<br><br>\left(\mathrm{\tau <br><br>}\right)=\{\begin{array}{c}-15,\mathrm{\tau <br><br>}=7\\ 1,\mathrm{\tau <br><br>}\ne <br><br>7\end{array}<br><br><br><br>R_{j,i}<br><br>\left(\mathrm{\tau <br><br>}+1\right)=\{\begin{array}{c}-15,\mathrm{\tau <br><br>}=7\\ 1,\mathrm{\tau <br><br>}\ne <br><br>7\end{array}& \left(2\right)\end{array}$

where R_i,j(τ

) is a cross-correlation function between a pair of pilot pattern sequences and i, j=1, 2, 3, . . . , 8.

10. An apparatus receiving a pilot pattern comprising:

a memory mapping and/or addressing block for storing pilot pattern sequences inputted and/or demodulated by slots, wherein the pilot pattern sequences have a relation based on one or both of the following;

$\begin{array}{cc}{R}_i<br><br>\left(\mathrm{\tau <br><br>}\right)=\{\begin{array}{c}15,\mathrm{\tau <br><br>}=0\\ -1,\mathrm{\tau <br><br>}\ne <br><br>0\end{array},i=1,2,\mathrm{\dots <br><br>}<br><br>\text{\hspace{1em}<br><br>},8& \left(1\right)\end{array}$

where R_i(τ

) is the auto-correlation function of the pilot pattern sequence, $\begin{array}{cc}{R}_{i,j}<br><br>\left(\mathrm{\tau <br><br>}\right)=\{\begin{array}{c}-15,\mathrm{\tau <br><br>}=7\\ 1,\mathrm{\tau <br><br>}\ne <br><br>7\end{array}<br><br><br><br>R_{j,i}<br><br>\left(\mathrm{\tau <br><br>}+1\right)=\{\begin{array}{c}-15,\mathrm{\tau <br><br>}=7\\ 1,\mathrm{\tau <br><br>}\ne <br><br>7\end{array}& \left(2\right)\end{array}$

where R_i,j(τ

) is a cross-correlation function between a pair of pilot pattern sequences and i, j=1, 2, 3, . . . , 8.