System and method for transmitting a synchronization signal

Patent metadata

Field	Value
Publication number	US-9615341-B2
Application number	US-201414530322-A
Country	US
Kind code	B2
Filing date	Oct 31, 2014
Priority date	Nov 1, 2013
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

A method for device-to-device (D2D) communications includes generating, by a synchronization source, a primary device-to-device synchronization signal that is different from a primary synchronization signal (PSS) sent by an Evolved NodeB (eNodeB) and an existing uplink (UL) signal sent by device-to-device communications devices, and transmitting, by the synchronization source, the primary device-to-device synchronization signal in a single carrier frequency division multiple access (SC-FDMA) waveform.

First claim

What is claimed is:

1. A method for device-to-device communications, the method comprises:
generating, by a synchronization source, a primary device-to-device synchronization signal that is different from a primary synchronization signal (PSS) sent by an Evolved NodeB (eNodeB) and an existing uplink (UL) signal sent by device-to-device communications devices, wherein generating the primary device-to-device synchronization signal comprises:
generating a synchronization sequence in accordance with a first sequence, wherein a first root index of the first sequence is different from a second root index of a second sequence used to generate the PSS; and
mapping the synchronization sequence onto subcarriers to produce the primary device-to-device synchronization signal; and

transmitting, by the synchronization source, the primary device-to-device synchronization signal in a single carrier frequency division multiple access (SC-FDMA) waveform.

2. The method of claim 1 , wherein generating the primary device-to-device synchronization signal comprises:
generating the synchronization sequence further in accordance with a third root index of a third sequence used to generate the existing UL signal.

3. The method of claim 1 , wherein the first sequence comprises a first punctured Zadoff-Chu (ZC) sequence, and wherein the second sequence comprises a second punctured ZC sequence.

4. The method of claim 3 , wherein the first punctured ZC sequence and the second punctured ZC sequence are the same.

5. The method of claim 1 , wherein mapping the primary device-to-device synchronization signal comprises mapping the synchronization sequence to the subcarriers so that the primary device-to-device synchronization signal is centrally symmetric.

6. The method of claim 5 , wherein for N samples of the primary device-to-device synchronization signal, a central symmetry is according to s[k]=−s[N−k], k=1, . . . , N−1, where N is an integer value.

7. The method of claim 1 , wherein the primary device-to-device synchronization signal is generated in accordance with a synchronization sequence

s
u

⁡

(
t
)

=

∑

k
=

-
N

/
2

N
/
2

-
1

⁢

H
u

⁡

[
k
]

·

ⅇ

j
⁢

⁢
2
⁢

⁢

π
⁡

(

k
+
δ

)

⁢
Δ
⁢

⁢
ft

,

0
≤
t
<

1

Δ
⁢

⁢
f

=

N
·

T
S

,

and wherein the synchronization sequence is mapped to at most N coefficients of H[ ], where T s is a sampling period, Δf is a subcarrier spacing, u is the first root index, N=1/T s Δf, and δ=½.

8. The method of claim 7 , wherein the synchronization sequence is expressible as

d
u

⁡

(
n
)

=

{

ⅇ

-

j

π
⁢

⁢

un
⁡

(

n
+
1

)

63

n
=
0

,
1
,
…
⁢

,
30

Assignees

• Futurewei Technologies Inc

Inventors

• Sartori Philippe
• Xia Liang
• Li Qiang
• Popovic Branislav
• Berggren Fredrik

Classifications

• H04W72/21

  in the uplink direction of a wireless link, i.e. towards the network · CPC title

• H04W56/001 Primary

  Synchronization between nodes · CPC title

• H04J2011/0096

  Network synchronisation · CPC title

• H04J11/0073 Primary

  Acquisition of primary synchronisation channel, e.g. detection of cell-ID within cell-ID group · CPC title

• H04J11/00

  Orthogonal multiplex systems, {e.g. using WALSH codes}(H04J13/00 takes precedence) · CPC title