# US 9,438,327 B2 · Method for operating a secondary station

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- Number: US 9,438,327 B2
- Document ID: US9438327B2
- Status: Granted
- Kind: B2
- Application number: 14/634,967
- Filed: 2015-03-02
- Published: 2015-07-16
- Granted: 2016-09-06
- Earliest claimed: 2010-04-02
- Assignees: Koninklijke Philips N.V.
- Applicants: Koninklijke Philips N.V.
- Inventors: Timothy James Moulsley; Milos Tesanovic
- Web page: https://patentgrep.com/patent/US9438327B2

## CPC

- H04B 7/063: {Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection}
- H04B 7/0456: Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
- H04L 1/0025: {Transmission of mode-switching indication}
- H04L 1/0029: {Reduction of the amount of signalling, e.g. retention of useful signalling or differential signalling (power control H04W52/04)}
- H04B: TRANSMISSION
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

The invention relates to a method for operating a secondary station, the secondary station communicating with at least one primary station by means of MIMO transmissions, the method comprising the secondary station signaling a single precoding indicator representative of a set of recommended precoding coefficients to the primary station, wherein the same set precoding indicator applies for a plurality of available transmission modes.

## Claims

### Claim 1

A method for operating a secondary station, communicating in a multiple-input multiple-output (MIMO) wireless transmission system, with at least one primary station the method comprising the acts of:
in the secondary station:
signaling in a transmitter, a single precoding indicator representative of at least one set of recommended precoding coefficients to the primary station, wherein the same single precoding indicator applies for a plurality of available transmission modes.

### Claim 2 (depends on 1)

The method of claim 1, wherein the plurality of available transmission modes includes at least one Single User-MIMO transmission mode, and at least one Multi User-MIMO transmission mode.

### Claim 3 (depends on 1)

The method of claim 1, wherein the plurality of available transmission modes includes at least one MIMO transmission mode with a first transmission rank range, and at least one MIMO transmission mode with a second transmission rank range.

### Claim 4 (depends on 1)

The method of claim 1, wherein the secondary station signals along with the single precoding indicator, a respective set of parameters for each transmission mode.

### Claim 5 (depends on 4)

The method of claim 4, wherein each set of parameters includes, for each respective transmission mode, at least one of the group of: a preferred rank of transmission, an achievable data rate, an estimate of an achievable data rate, and additional information for at least one of the available transmission modes indicating a different set of precoding coefficients than signaled by the single precoding indicator.

### Claim 6 (depends on 1)

The method of claim 1, comprising the secondary station determining a set of recommended precoding coefficients for at least one of the available transmission modes to be signaled to the primary station by signaling only the single precoding indicator.

### Claim 7 (depends on 6)

The method of claim 6, wherein the set of recommended precoding coefficients is selected out of a precoding codebook including a set of precoding matrices, and wherein the precoding indicator is a precoding matrix indicator representative of an index to an entry in the precoding codebook.

### Claim 8 (depends on 6)

The method of claim 6, wherein the secondary station selects the set of recommended precoding coefficients, such that a joint rate is maximized, the joint rate being based on a weighted sum of the rates for rank 1 and the rank which gives the highest rate.

### Claim 9 (depends on 8)

The method of claim 8, wherein the secondary station selects the set of recommended precoding coefficients corresponding to index i, and/or selects a rank from the set of possible ranks rk={rk,1; . . . ; rk,n} for at least one transmission mode, k, such that the rate:
R
⁡
(
i
)
=
∑
k
=
1
m
⁢
α
k
⁢
R
MIMOk
⁡
(
i
,
r
k
)
,
is maximized, where 0≦αk<1, R(i) is the joint data rate, and RMIMOk is the estimated data rate of the MIMO transmission mode k.

### Claim 10 (depends on 9)

The method of claim 9, wherein
∑
k
=
1
m
⁢
α
k
=
1.

### Claim 11 (depends on 9)

The method of claim 9, wherein the secondary station reports to the primary station an estimated rate based on the product of the selected transmission rank and the data rate obtained for the set of recommended precoding coefficients with a predetermined rank.

### Claim 12 (depends on 11)

The method of claim 11, wherein the predetermined rank is 1.

### Claim 13 (depends on 12)

The method of claim 12, wherein the secondary station reports a joint rate which is determined from a combined weighted rate
Rav=δroptRSU(iopt,1)+εRSU(iopt,ropt)
where δ and ε are weights, ropt, is the optimal rank, iopt is the set of optimal precoding coefficients, and RSU(i,r) is the data rate for the transmission mode with rank r, and the set of precoding coefficients i.

### Claim 14 (depends on 8)

The method of claim 8, wherein the joint rate is reported to the primary station.

### Claim 15 (depends on 14)

The method of claim 14, wherein the rate reported to the primary station is in the form of a plurality of rates.

### Claim 16 (depends on 15)

The method of claim 15, wherein the plurality of rates each correspond to at least one of a plurality of transmission modes and/or a plurality of codewords.

### Claim 17

A primary station communicating in a multiple-input-multiple-output (MIMO) wireless transmission system, with at least one secondary station, the primary station comprising:
a plurality of transmit antennas,
a transmitter coupled to the plurality of transmit antennas,
a plurality of receive antennas,
a receiver, coupled to a plurality of receive antennas,
a controller connected to the transmitter and receiver, configured to receive from the secondary station a single precoding indicator representative of at least one set of recommended precoding coefficients, wherein the same single precoding indicator applies for a plurality of available transmission modes, and
the controller being configured for selecting a transmission mode out of the plurality of available transmission mode based at least partly on the single precoding indicator.

### Claim 18 (depends on 17)

The primary station of claim 17, wherein the plurality of available transmission modes includes at least one Single User-MIMO transmission mode, and at least one Multi User-MIMO transmission mode.

### Claim 19 (depends on 17)

The primary station of claim 17, wherein the plurality of available transmission modes includes at least one MIMO transmission mode with a first transmission rank range, and at least one MIMO transmission mode with a second transmission rank range.

### Claim 20 (depends on 17)

The primary station of claim 17, wherein the receiver additionally receives along with the single precoding indicator, a respective set of parameters for each transmission mode.

### Claim 21 (depends on 20)

The primary station of claim 20, wherein each set of parameters includes, for each respective transmission mode, at least one of the group of: the preferred rank of transmission, an achievable data rate, an estimate of an achievable data rate, and additional information for at least one of the available transmission modes indicating a different set of precoding coefficients than signaled by the single precoding indicator.

### Claim 22 (depends on 17)

The primary station of claim 17, wherein the receiver, receives a joint rate from the at least one secondary station.

### Claim 23 (depends on 22)

The primary station of claim 22, wherein the at least one secondary station selects a set of recommended precoding coefficients, such that the joint rate is maximized, the joint rate being based on a weighted sum of the rates for rank 1 and the rank which gives the highest rate.

### Claim 24 (depends on 17)

The primary station of claim 17, wherein the receiver receives an estimated rate from the at least one secondary station, wherein the estimated rate is based on the product of a selected transmission rank and the data rate obtained for the set of recommended precoding coefficients with a predetermined rank, wherein the at least one secondary station selects the set of recommended precoding coefficients corresponding to index i, and/or selects a rank from the set of possible ranks rk={rk,1; . . . ; rk,n} for at least one transmission mode, k, such that the rate:
R
⁡
(
i
)
=
∑
k
=
1
m
⁢
α
k
⁢
R
MIMOk
⁡
(
i
,
r
k
)
is maximized, where 0≦αk<1, R(i) is the joint data rate, and RMIMOk is the estimated data rate of the MIMO transmission mode k.

### Claim 25 (depends on 24)

The primary station of claim 24, wherein
∑
k
=
1
m
⁢
α
k
=
1.

### Claim 26 (depends on 17)

The primary station of claim 17, comprising a precoder coupled to the controller and plurality of transmit antennas, configured to control the plurality of transmit antennas, to adjust the gain and phase of signals applied to the transmit antennas, to transmit signals to the at least one secondary station in a beamforming mode on one or more spatial channels.

### Claim 27

A secondary station communicating in a multiple-input-multiple-output (MIMO) wireless transmission system, with a primary station, the secondary station comprising:
a plurality of receive antennas,
a receiver coupled to the plurality of receive antennas,
a plurality of transmit antennas,
a transmitter, coupled to the plurality of transmit antennas, configured to transmit a single precoding indicator representative of at least one set of recommended precoding coefficients to the primary station, wherein the same single precoding indicator applies for a plurality of available transmission modes.

### Claim 28 (depends on 27)

The secondary station of claim 27, wherein the plurality of available transmission modes includes at least one Single User-MIMO transmission mode, and one Multi User-MIMO transmission mode.

### Claim 29 (depends on 27)

The secondary station of claim 27, wherein the plurality of available transmission modes includes at least one MIMO transmission mode with a first transmission rank range, and one MIMO transmission mode with a second transmission rank range.

### Claim 30 (depends on 27)

The secondary station of claim 27, wherein the secondary station signals along with the single precoding indicator, a respective set of parameters for each transmission mode.

### Claim 31 (depends on 30)

The secondary station of claim 30, wherein each set of parameters includes, for each respective transmission mode, at least one of the group of: a preferred rank of transmission, an achievable data rate, an estimate of an achievable data rate, and additional information for at least one of the available transmission modes indicating a different set of precoding coefficients than signaled by the single precoding indicator.

### Claim 32 (depends on 27)

The secondary station of claim 27, comprising the secondary station determining a set of recommended precoding coefficients for at least one of the available transmission modes to be signaled to the primary station by signaling only the single precoding indicator.

### Claim 33 (depends on 32)

The secondary station of claim 32, wherein the set of recommended precoding coefficients is selected out of a precoding codebook including a set of precoding matrices, and wherein the precoding indicator is a precoding matrix indicator representative of an index to an entry in the precoding codebook.

### Claim 34 (depends on 32)

The secondary station of claim 32, wherein the secondary station selects the set of recommended precoding coefficients, such that a joint rate is maximized, the joint rate being based on a weighted sum of the rates for rank 1 and the rank which gives the highest rate.

### Claim 35 (depends on 34)

The secondary station of claim 34, wherein the secondary station selects the set of recommended precoding coefficients corresponding to index i, and/or selects a rank from the set of possible ranks rk={rk,1; . . . ; rk,n} for at least one transmission mode, k, such that the rate:
R
⁡
(
i
)
=
∑
k
=
1
m
⁢
α
k
⁢
R
MIMOk
⁡
(
i
,
r
k
)
,
is maximized, where 0≦αk<1, R(i) is the joint data rate, and RMIMOk is the estimated data rate of the MIMO transmission mode k.

### Claim 36 (depends on 35)

The secondary station of claim 35, wherein
∑
k
=
1
m
⁢
α
k
=
1.

### Claim 37 (depends on 35)

The secondary station of claim 35, wherein the secondary station reports to the primary station an estimated rate based on the product of the selected transmission rank and the data rate obtained for the set of recommended precoding coefficients with a predetermined rank.

### Claim 38 (depends on 37)

The secondary station of claim 37, wherein the predetermined rank is 1.

### Claim 39 (depends on 38)

The secondary station of claim 38, wherein the secondary station reports a joint rate which is determined from a combined weighted rate
Rav=δroptRSU(iopt,1)+εRSU(iopt,ropt)
where δ and ε are weights, ropt is the optimal rank, iopt is the set of optimal precoding coefficients, and RSU(i,r) is the data rate for the transmission mode with rank r, and the set of precoding coefficients i.

### Claim 40 (depends on 34)

The secondary station of claim 34, wherein the joint rate is reported to the primary station.

### Claim 41 (depends on 40)

The secondary station of claim 40, wherein the rate reported to the primary station is in the form of a plurality of rates.

### Claim 42 (depends on 41)

The secondary station of claim 41, wherein the plurality of rates each correspond to at least one of a plurality of transmission modes and/or a plurality of codewords.

### Claim 43 (depends on 27)

The secondary station of claim 27, comprising a precoder coupled to the controller and plurality of transmit antennas, configured to control the plurality of transmit antennas, to adjust the gain and phase of signals applied to the transmit antennas, to transmit signals to the at least one secondary station in a beamforming mode on one or more spatial channels.

### Claim 44

A tangible computer-readable storage medium that is not a transitory propagating signal or wave, encoded with control information including instructions, for controlling a primary station for performing a method for communication in a multiple-input-multiple-output (MIMO) wireless transmission system, with at least one secondary station, the method comprising:
at the primary station:
receiving in a transceiver of the primary station, from the secondary station, a single precoding indicator representative of at least one set of recommended precoding coefficients, wherein the same single precoding indicator applies for a plurality of available transmission modes; and
selecting in a controller, a transmission mode out of the plurality of available transmission modes based at least partly on the single precoding indicator.

### Claim 45

A tangible computer-readable storage medium that is not a transitory propagating signal or wave, encoded with control information including instructions, for controlling a secondary station for performing a method for communication in a multiple-input-multiple-output (MIMO) wireless transmission system, with a primary station, the method comprising:
at the secondary station:
a transmitter signaling a single precoding indicator representative of at least one set of recommended precoding coefficients to the primary station, wherein the same single precoding indicator applies for a plurality of available transmission modes.

### Claim 46

A method for operating a primary station, for communication in a multiple-input-multiple-output (MIMO) wireless transmission system, with at least one secondary station, the method comprising:
in the primary station:
a receiver, receiving from the secondary station a single precoding indicator representative of at least one set of recommended precoding coefficients, wherein the same single precoding indicator applies for a plurality of available transmission modes; and
a controller selecting a transmission mode out of the plurality of available transmission mode based at least partly on the single precoding indicator.

### Claim 47 (depends on 46)

The method of claim 46, wherein the plurality of available transmission modes includes at least one Single User-MIMO transmission mode, and one Multi User-MIMO transmission mode.

### Claim 48 (depends on 46)

The method of claim 46, wherein the plurality of available transmission modes includes at least one MIMO transmission mode with a first transmission rank range, and one MIMO transmission mode with a second transmission rank range.

### Claim 49 (depends on 46)

The method of claim 46, wherein the secondary station signals along with the single precoding indicator, a respective set of parameters for each transmission mode.

### Claim 50 (depends on 49)

The method of claim 49, wherein each set of parameters includes for each respective transmission mode at least one of the following group: the preferred rank of transmission, an achievable data rate, an estimate of an achievable data rate, and additional information for at least one of the available transmission modes indicating a different set of precoding coefficients than signaled by the single precoding indicator.

### Claim 51 (depends on 46)

The method of claim 46, comprising the secondary station determining a set of recommended precoding coefficients for at least one of the available transmission modes to be signaled to the primary station by signaling only the single precoding indicator.

### Claim 52 (depends on 51)

The method of claim 51, wherein the set of recommended precoding coefficients is selected out of a precoding codebook including a set of precoding matrices, and wherein the precoding indicator is a precoding matrix indicator representative of an index to an entry in the precoding codebook.

### Claim 53 (depends on 52)

The method of claim 52, wherein the secondary station selects the set of recommended precoding coefficients, such that a joint rate is maximized, the joint rate being based on a weighted sum of the rates for rank 1 and the rank which gives the highest rate.