Channel state information-reference signal patterns for time division duplex systems in long term evolution wireless networks

Patent metadata

Field	Value
Publication number	US-9455811-B2
Application number	US-201314126599-A
Country	US
Kind code	B2
Filing date	Sep 27, 2013
Priority date	Jan 17, 2013
Publication date	Sep 27, 2016
Grant date	Sep 27, 2016

Abstract

A user equipment (UE) for time division duplex (TDD) communication through a wireless communication channel has a receiver to receive a channel state information reference signal (CSI-RS) subframe configuration value, a CSI-RS configuration value, and a CSI-RS; and circuitry to determine a subframe index corresponding to a temporal position of a special subframe including the CSI-RS; determine a CSI-RS pattern of one or more orthogonal frequency division modulation (OFDM) resource elements carrying the CSI-RS, the pattern being from among a group of CSI-RS patterns that include OFDM resource elements in OFDM symbols corresponding to a physical downlink control channel (PDCCH) region of a legacy LTE wireless communication channel; control the receiver to receive the special subframe carrying the CSI-RS during the temporal position and at the one or more OFDM resource elements of the CSI-RS pattern; and measure the wireless communication channel based on the CSI-RS.

First claim

The invention claimed is:

1. A user equipment (UE) for time division duplex (TDD) communication through a wireless communication channel with an evolved Node B (eNB), the TDD communication having a radio frame including an uplink subframe and a special subframe preceding the uplink subframe, the UE comprising:
a receiver configured to receive from the eNB, a channel state information reference signal (CSI-RS) subframe configuration value, a CSI-RS configuration value, and a CSI-RS; and
circuitry configured to:
determine, based on the CSI-RS subframe configuration value, a subframe index corresponding to a temporal position of a special subframe including the CSI-RS in the radio frame;
determine, based on the CSI-RS configuration value, a CSI-RS pattern of one or more orthogonal frequency division modulation (OFDM) resource elements carrying the CSI-RS, the pattern being from among a group of CSI-RS patterns that include OFDM resource elements in OFDM symbols corresponding to a physical downlink control channel (PDCCH) region of a long term evolution (LTE) wireless communication channel;
control the receiver to receive from the eNB the special subframe carrying the CSI-RS during the temporal position and at the one or more OFDM resource elements of the CSI-RS pattern; and
measure the wireless communication channel based on the CSI-RS, in which the CSI-RS subframe configuration value has a value according to an expression 1+(x*5), where x satisfies the relationship 0≦x≦30.

2. The UE of claim 1 , in which the circuitry is further configured to:
determine a CSI-RS subframe offset defining an initial subframe index corresponding to a first temporal position of the special subframe including the CSI-RS in the radio frame; and
determine a CSI-RS subframe periodicity defining a number of subframes between the initial subframe index and a subsequent subframe index corresponding to a second temporal position of a second special subframe including the CSI-RS, so as to periodically receive the CSI-RS in special subframes.

3. The UE of claim 1 , in which the special subframe includes a downlink pilot time slot (DwPTS) having a predetermined duration, and in which the receiver is further configured to receive a special subframe configuration value corresponding to the predetermined duration, and in which the group of CSI-RS patterns are defined based on a number of OFDM symbols available in the predetermined duration.

4. The UE of claim 3 , in which the group of CSI-RS patterns include patterns for special subframe configuration values corresponding to special subframe configurations having DwPTSs of less than four OFDM symbols.

5. The UE of claim 1 , in which the group of CSI-RS patterns comprise a predetermined group of CSI-RS patterns selected to avoid collision between CSI-RSs and a cell-specific reference signal (CRS) for antenna port zero.

6. The UE of claim 1 , in which the group of CSI-RS patterns are predefined according to an equation and a mapping of CSI-RS configuration values to an OFDM sub-carrier position k′ and an OFDM symbol position l′, in which the equation yields, for a given number of 1 and 2, 4, or 8 antenna ports and a given OFDM sub-carrier position k′ and symbol position l′, a set of CSI-RS resource elements corresponding to 1 and 2, 4, or 8 antenna ports.

7. The UE of claim 6 , in which the equation and the mapping include multiple equations and mappings, in which each of different ones of the equations and mappings correspond to a number of OFDM symbols available in a subframe configuration value.

8. A method of receiving a channel state information reference signal (CSI-RS), the method comprising:
receiving from an evolved Node B (eNB) information indicating that the CSI-RS is carried in a special subframe preceding an uplink subframe;
receiving from the eNB CSI-RS configuration information indicating a position of the CSI-RS in a pattern of resource elements of an OFDM transmission made in the special subframe, in which the pattern comprises CSI-RS subcarriers k and symbols l;
determining, based on the CSI-RS configuration information, the pattern according to an equation and a predetermined table, the predetermined table having pairs of subcarrier position k′ and symbol position l′ corresponding to a resource element, the pairs including resource elements in at least one of an initial pair of OFDM symbols of a resource block, and the equation identifying the CSI-RS subcarriers k and symbols l based on an antenna port value, an index of resource blocks in the special subframe, and a selected pair of subcarrier position k′ and a symbol position l′; and
receiving the CSI-RS at the subcarriers k and symbols l, in which the CSI-RS configuration information comprises an index for the pairs of subcarrier position k′ and symbol position l′ of the predetermined table, and in which the determining comprises:
selecting, based on the index, a pair of subcarrier position k′ and symbol position l′ from the predetermined table; and
mapping the pair of subcarrier position k′ and symbol position l′ to the CSI-RS subcarriers k and symbols l of the pattern based on the equation that includes the following expression:

k
=

k
′

+

12
⁢
m

+

{

-
0

for
⁢

⁢
p

∈

{

15
,
16

}

,

normal
⁢

⁢
cyclic
⁢

⁢
prefix

-
6

Assignees

• Intel Ip Corp

Inventors

• He Hong
• Davydov Alexei
• Han Seunghee
• Fwu Jong-Kae
• Bashar Shafi

Classifications

• H04L5/14

  Two-way operation using the same type of signal, i.e. duplex · CPC title

• H04L5/1469

  using time-sharing · CPC title

• H04L27/2613

  Structure of the reference signals · CPC title

• H04W28/06

  Optimizing {the usage of the radio link}, e.g. header compression, information sizing {, discarding information (system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365)} · CPC title

• H04L5/0048 Primary

  Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091) · CPC title