# US 10,772,088 B2 · Control channels for wireless communication

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- Number: US 10,772,088 B2
- Document ID: US10772088B2
- Status: Granted
- Kind: B2
- Application number: 15/879,086
- Filed: 2018-01-24
- Published: 2018-05-31
- Granted: 2020-09-08
- Earliest claimed: 2012-08-02
- Assignees: Fujitsu Limited
- Applicants: Fujitsu Limited
- Inventors: Timothy Moulsley
- Web page: https://patentgrep.com/patent/US10772088B2

## CPC

- H04W 72/23: in the downlink direction of a wireless link, i.e. towards a terminal
- H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals}
- H04L 5/0096: {Indication of changes in allocation}
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

Wireless communication method where a wireless network transmits a control channel message to a terminal. At the wireless network side: configuring a plurality of search spaces, each of the plurality are configured from a plurality of control channel elements within a sub-frame by using a pseudorandom function; determining one or more control channel elements to use for transmission of the control channel message from the plurality of search spaces; and transmitting the control channel message. At the terminal side: decoding the control channel message by making a selection of locations for blind decoding the search space within the sub-frame, using the pseudorandom function. The pseudo-random function is a function based on a sum of a first value and a second value. The first value is a pseudo-random factor, and the second value is based on an aggregation level and a total of control channel elements in the sub-frame.

## Claims

### Claim 1

A wireless communication method in which a wireless network transmits a control channel message for receipt by a terminal, the method comprising,
at the wireless network side:
configuring a plurality of search spaces, each of the plurality of search spaces being configured from a plurality of control channel elements within a subframe by using a pseudorandom function;
determining one or more control channel elements to use for transmission of the control channel message within the plurality of search spaces; and
transmitting the control channel message located in the one or more control channel elements; and
at the terminal side:
decoding the control channel message by making a selection of locations for blind decoding the plurality of search spaces within the subframe, using the pseudorandom function,
wherein, the pseudo-random function is a function based on a sum of a first value and a second value,
wherein the first value is a pseudo-random factor, and the second value is based on an aggregation level and a total of control channel elements in the subframe.

### Claim 2 (depends on 1)

The method according to claim 1, wherein resources corresponding to a search space for each of the plurality of control channel elements are configured such that the resources are adjacently located in adjacent frequency domain locations.

### Claim 3 (depends on 1)

The method according to claim 1, wherein an amount of resources used for the transmission of the control channel message has one of a plurality of sizes depending on the aggregation level.

### Claim 4 (depends on 1)

The method according to claim 1, applied to an enhanced Physical Downlink Control Channel, ePDCCH of an LTE-based wireless communication system wherein each of the control channel messages occupies one or more enhanced Control Channel Elements, eCCEs within a given subframe.

### Claim 5 (depends on 4)

The method according to claim 4 wherein resources for the ePDCCH are divided in frequency domain into pairs of Physical Resource Blocks (PRBS) to which the eCCEs are mapped, resources corresponding to each search space comprise a set of PRB pairs, and said selection comprises selecting a PRB pair from the set using said pseudo-random function.

### Claim 6 (depends on 4)

The method according to claim 4 wherein the selection is made based on the following pseudo-random function:
L{((Yk+O′k,m,L,)mod|N′eCCE,k,m,L/L/+Ok,m,L)mod|NeCCE,k/L|}+i
where L is the aggregation level, m is a ePDCCH candidate corresponding to eCCEs of the search space, k is a subframe for the transmission of the control channel message, NeCCE, k is a total number of eCCEs available in the subframe k, N′eCCE, k,m,L is a number of eCCEs within which the ePDCCH candidate may be located, Ok,m,L is an offset within the total number of the eCCEs or a subset of the eCCEs for the subframe k, the ePDCCH candidate and the aggregation level, O′k, m,L is an offset within the subset of the eCCEs defined for the subframe k, the ePDCCH candidate m and the aggregation level L, Yk is the pseudo-random factor based on the subframe k and a radio network temporary identifier, and i=0 . . . , L−1.

### Claim 7 (depends on 1)

The method according to claim 1 wherein the pseudo-random factor is defined as:
Y
k
=
(
A
·
Y
k
-
1
)
⁢
⁢
mod
⁢
⁢
D
where Y−1=nRNTI≠0, A and D are different fixed values, k depends on a slot number and RNTI is radio network temporary identifier.

### Claim 8 (depends on 1)

The method according to claim 1 wherein the plurality of the control channel elements are configured from available resource.

### Claim 9

A base station for use in a wireless communication system and arranged to transmit a control channel message, the base station comprising:
a configurer configured to configure a plurality of search spaces, each of the plurality of search spaces being configured from a plurality of control channel elements within a subframe by using a pseudo-random function;
a scheduler configure to determine one or more control channel elements to use for transmission of the control channel message within the plurality of search spaces, and
a transmitter configured to transmit the control channel message located in the one or more control channel elements,
wherein, the pseudo-random function is a function based on a sum of a first value and a second value,
wherein the first value is a pseudo-random factor, and the second value is based on an aggregation level and a total of control channel elements in the subframe.

### Claim 10 (depends on 9)

The base station according to claim 9, wherein an amount of resources used for the transmission of the control channel message has one of a plurality of sizes depending on the aggregation level.

### Claim 11 (depends on 9)

The base station according to claim 9, applied to an enhanced Physical Downlink Control Channel, ePDCCH of an LTE-based wireless communication system wherein each of the control channel messages occupies one or more enhanced Control Channel Elements, eCCEs within a given subframe.

### Claim 12 (depends on 11)

The base station according to claim 11 wherein a selection is made based on the following pseudo-random function:
L{((Yk+O′k,m,L,)mod|N′eCCE,k,m,L/L|+Ok,m,L)mod|NeCCE,k/L|}+i
where L is the aggregation level, m is a ePDCCH candidate corresponding to eCCEs of the search space, k is a subframe for the transmission of the control channel message, NeCCE, k is a total number of eCCEs available in the subframe k, N′eCCE, k,m,L is a number of eCCEs within which the ePDCCH candidate may be located, Ok,m,L is an offset within the total number of the eCCEs or a subset of the eCCEs for the subframe k, the ePDCCH candidate and the aggregation level, O′k, m,L is an offset within the subset of the eCCEs defined for the subframe k, the ePDCCH candidate m and the aggregation level L, Yk is the pseudo-random factor based on the subframe k and a radio network temporary identifier, and i=0 . . . , L−1.

### Claim 13 (depends on 9)

The base station according to claim 9 wherein the pseudo-random factor is defined as:
Y
k
=
(
A
·
Y
k
-
1
)
⁢
⁢
mod
⁢
⁢
D
where Y−1=nRNTI≠0, A and D are different fixed values, k depends on a slot number and RNTI is radio network temporary identifier.

### Claim 14 (depends on 9)

The base station according to claim 9 wherein the plurality of the control channel elements are configured from available resource.

### Claim 15

A terminal for use in a wireless communication network, the wireless communication network arranged to transmit at least one control channel message to the terminal, wherein the terminal comprises:
a receiver configured to receive the at least one control channel message located in one or more control channel elements within a plurality of search spaces, each of the plurality of search spaces being configured from a plurality of control channel elements within a subframe by using a pseudorandom function;
a decoder configured to decode the control channel message by making a selection of locations for blind decoding the plurality of search spaces within the subframe, using the pseudorandom function,
wherein, the pseudo-random function is a function based on a sum of a first value and a second value,
wherein the first value is a pseudo-random factor, and the second value is based on an aggregation level and a total of control channel elements in a subframe.

### Claim 16 (depends on 15)

The terminal according to claim 15, wherein an amount of resources used for the transmission of the control channel message has one of a plurality of sizes depending on the aggregation level.

### Claim 17 (depends on 15)

The terminal according to claim 15, applied to an enhanced Physical Downlink Control Channel, ePDCCH of an LTE-based wireless communication system wherein each of the control channel messages occupies one or more enhanced Control Channel Elements, eCCEs within a given subframe.

### Claim 18 (depends on 17)

The terminal according to claim 17 wherein the selection is made based on the following pseudo-random function:
L{((Yk+O′k,m,L,)mod|N′eCCE,k,m,L/L|+Ok,m,L)mod|NeCCE,k/L|}+i
where L is the aggregation level, m is a ePDCCH candidate corresponding to eCCEs of the search space, k is a subframe for the transmission of the control channel message, NeCCE, k is a total number of eCCEs available in the subframe k, N′eCCE, k,m,L is a number of eCCEs within which the ePDCCH candidate may be located, Ok,m,L is an offset within the total number of the eCCEs or a subset of the eCCEs for the subframe, the ePDCCH candidate and the aggregation level, O′k, m,L is an offset within the subset of the eCCEs defined for the subframe k, the ePDCCH candidate m and the aggregation level L, Yk is the pseudo-random factor based on the subframe k and a radio network temporary identifier, and i=0 . . . , L−1.

### Claim 19 (depends on 15)

The terminal according to claim 15 wherein the pseudo-random factor is defined as:
Y
k
=
(
A
·
Y
k
-
1
)
⁢
⁢
mod
⁢
⁢
D
where Y−1=nRNTI≠0, A and D are different fixed values, k depends on a slot number and RNTI is radio network temporary identifier.

### Claim 20 (depends on 15)

The terminal according to claim 15 wherein the plurality of the control channel elements are configured from available resource.