Zero insertion for isi free ofdm reception

Patent metadata

Field	Value
Publication number	US-2016006586-A1
Application number	US-201314767018-A
Country	US
Kind code	A1
Filing date	Feb 12, 2013
Priority date	Feb 12, 2013
Publication date	Jan 7, 2016
Grant date	—

Abstract

An apparatus (UEA) may generate a zero-tail signal to be transmitted in an LTE/LTE-A cell, by introducing time domain samples with zero power or very low power in specific positions of a time symbol tail. The apparatus (UEA) may transmit the generated zero-tail signal to a base station (eNB), such that a first user terminal (UEA) is located in the cell farther away (e.g. on a cell egde) from the base station (eNB) than a second user terminal (UEB). Thus coexistence of signals sent by user terminals (UEA, UEB) located at different distances from the base station (eNB) within a same receiver window is enabled without inter-symbol interference. The generated zero-tail signal may also be transmitted from the first user terminal (UEA) or from the base station (eNB) in an outdoor system that is detectable by a neighbouring indoor system.

First claim

1 . A method for providing a signal in a communications system, comprising:
generating a cyclic zero-tail signal to be transmitted in a cell, by introducing time domain samples with zero power or very low power in specific positions of a time symbol tail; controlling the amount of zero power or very low power samples; and transmitting the generated cyclic zero-tail signal between communication devices.

2 . A method according to claim 1 , wherein the amount of the zero power or very low power samples is dependent on one or more of:
a distance between the communication devices, a cell size of the cell which a communication device is connected to, and synchronization accuracy between the communication devices.

3 - 4 . (canceled)

5 . A method according to claim 1 , characterized in that the zero-tail signal is generated by introducing a zero word in the last part of time symbols to be transmitted.

6 . A method according to claim 1 , wherein the step of transmitting the generated cyclic zero-tail signal between communication devices comprises at least one of the following:
transmitting the generated zero-tail signal from a first user terminal to a base station, wherein the first user terminal is located in the cell farther away from the base station than a second user terminal; and transmitting the generated zero-tail signal from the first user terminal or from the base station in an outdoor system that is detectable by a neighbouring indoor system.

7 . A method according to claim 6 , wherein the first user terminal is located in an outdoor cell and the second user terminal in an indoor cell, and wherein the generated zero-tail signal is transmitted from the first user terminal or from the base station in an outdoor system that is detectable by a neighbouring indoor system.

8 . A method according to claim 6 , wherein the first user terminal is located on an edge of the cell, wherein the generated zero-tail signal is transmitted from the first user terminal to a base station, and the first user terminal is located in the cell farther away from the base station than the second user terminal.

9 . A method according to claim 6 , wherein the second user terminal is located in the proximity of the base station.

10 . A method according to claim 1 , further comprising enabling coexistence of uplink signals sent by user terminals located at different distances from the base station within a same receiver window.

11 . A method according to claim 6 , further comprising enabling maintaining of orthogonality of symbols sent by the first user terminal and the second user terminal.

12 . A method according to claim 1 , characterized by the zero-tail signal being an OFDM signal or a SC-FDM signal.

13 . (canceled)

14 . A method according to claim 1 , further comprising time domain zeros being located in the zero-tail signal in positions defined by vectors

P
0
A

=

⌈

T
F

-

(

τ
D

+

τ
S

)

T
S

⌉

+

1


:



⌈

T
F

-

T
CP

T
S

⌉

,
and

P
0
B

=

⌈

T
F

-

(

τ
D

+

τ
S

-

T
CP

)

T
S

⌉

+

1


:



⌈

T
F

T
S

⌉

,

wherein
T F is an OFDM/SC-FDM symbol duration without a cyclic prefix,
T CP is a cyclic prefix duration,
T S is a sampling time of the system,
τ D is a propagation delay,
τ S is a delay spread,
┌a┐ rounds a to a nearest integer bigger than a,
a:b indicates samples from a to b of the vector.

15 . A method according to claim 14 , characterized in that, in case (τ D +τ S )≧2T CP , P 0 A and P 0 B are contiguous or partially overlapped vectors, wherein

P
0
A

⋃

P
0
B

=

P
0

=

Assignees

• Nokia Solutions & Networks Oy

Inventors

• Berardinelli Gilberto
• Raaf Bernard
• Tavares Fernando
• Michel Juergen

Classifications

• H04W88/08

  Access point devices · CPC title

• H04W88/02

  Terminal devices · CPC title

• H04L27/2607

  Cyclic extensions · CPC title

• H04L25/03343

  Arrangements at the transmitter end · CPC title

• H04L25/03821 Primary

  Inter-carrier interference cancellation [ICI] · CPC title