Downlink baseband signal generating method, relevant device and system

• US 8,705,483 B2
• Filed: 12/11/2012
• Issued: 04/22/2014
• Est. Priority Date: 12/21/2010
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Liu, Sheng
• Primary Examiner(s): Kizou, Hassan
• Assistant Examiner(s): Daya, Tejis
• Application Number:
  US13/711,541
• Publication Number:
  US 20130100907A1
• Time in Patent Office: 497 Days
• Field of Search: 370/329, 455/501
• US Class Current: 370/329
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

The downlink baseband signal generating method includes: performing channel coding and modulation on a downlink data stream of a user in a cell, and obtaining a downlink coded and modulated user signal of the cell; generating a downlink control channel signal according to physical-layer control information; and forwarding the reference signal, synchronization signal, broadcast channel signal, downlink coded and modulated user signal, and downlink control channel signal to the corresponding RRU, so that the corresponding RRU performs MIMO precoding on the downlink coded and modulated user signal, maps the MIMO-precoded signal, the downlink control channel signal, reference signal, synchronization signal, and broadcast channel signal to their respective subcarriers, performs IFFT transformation to obtain a downlink baseband signal, and sends the signal out. The embodiments of the present invention can reduce the signal transmission bandwidth between the C-RAN node and the RRU.

Claims

1. A downlink baseband signal generating method, implemented by a radio access network node at a distributed base station with remote radio, comprising:

performing channel coding and modulation on a downlink data stream of a user in a cell, and obtaining a downlink coded and modulated user signal of the cell;

generating a downlink control channel signal according to physical-layer control information; and

forwarding a reference signal, a synchronization signal, a broadcast channel signal, the downlink coded and modulated user signal, and the downlink control channel signal to a corresponding remote radio unit, so that the corresponding remote radio unit performs multi-input multi-output precoding on the downlink coded and modulated user signal, maps the downlink coded and modulated user signal that has undergone the multi-input multi-output precoding, the downlink control channel signal, the reference signal, the synchronization signal, and the broadcast channel signal to their respective subcarriers, performs inverse fast Fourier transformation to obtain a downlink baseband signal, and sends the downlink baseband signal out.

2. The downlink baseband signal generating method according to claim 1, wherein:

the forwarding the reference signal, the synchronization signal, the broadcast channel signal, the downlink coded and modulated user signal, and the downlink control channel signal to the corresponding remote radio unit comprises;

forwarding the reference signal, the synchronization signal, the broadcast channel signal, the downlink coded and modulated user signal, and the downlink control channel signal to the corresponding remote radio unit according to a preset forwarding configuration list, wherein

the preset forwarding configuration list is used to record a mapping relationship between user information and a remote radio unit identifier.

3. The downlink baseband signal generating method according to claim 1, wherein:

the downlink control channel signal carries transmission resource indication information, and the transmission resource indication information indicates subcarriers that correspond to the downlink coded and modulated user signal that has undergone the multi-input multi-output precoding and the downlink control channel signal respectively, so that the remote radio unit maps the downlink coded and modulated user signal that has undergone the multi-input multi-output precoding and the downlink control channel signal onto their respective subcarriers according to the transmission resource indication information.

4. The downlink baseband signal generating method according to claim 1, wherein:

if the cell and one or more other cells employ coordinated multi-point processing based on Network-MIMO on a physical layer, the method further comprises;

forwarding downlink coded and modulated user signals of the one or more other cells to the corresponding remote radio unit, so that the corresponding remote radio unit performs joint multi-input multi-output precoding on the downlink coded and modulated user signal of the cell and the downlink coded and modulated user signals of the one or more other cells, maps the downlink coded and modulated user signal of the cell and the downlink coded and modulated user signals of the one or more other cells that have undergone the joint multi-input multi-output precoding, the downlink control channel signal, the reference signal, the synchronization signal, and the broadcast channel signal onto their respective subcarriers, performs the inverse fast Fourier transformation to obtain a downlink baseband signal, and sends the downlink baseband signal out, wherein the transmission resource indication information further indicates subcarriers that correspond to the downlink coded and modulated user signal of the cell and the downlink coded and modulated user signals of the one or more other cells that have undergone the joint multi-input multi-output precoding and the downlink control channel signal respectively, so that the remote radio unit maps the downlink coded and modulated user signal of the cell and the downlink coded and modulated user signals of the one or more other cells that have undergone the joint multi-input multi-output precoding and the downlink control channel signal onto their respective subcarriers according to the transmission resource indication information.

5. A downlink baseband signal generating method, implemented by a remote radio unit at a distributed base station with remote radio, comprising:

receiving a downlink coded and modulated user signal and a downlink control channel signal of a specific cell, wherein the downlink coded and modulated user signal and the downlink control channel signal are forwarded by a radio access network node, the downlink coded and modulated user signal is obtained after the radio access network node performs channel coding and modulation on a downlink data stream of a user in the specific cell, and the downlink control channel signal is generated by the radio access network node according to physical-layer control information;

performing multi-input multi-output precoding on the downlink coded and modulated user signal;

receiving a reference signal, a synchronization signal, and a broadcast channel signal that are forwarded by the radio access network node; and

mapping the downlink coded and modulated user signal that has undergone the multi-input multi-output precoding, the downlink control channel signal, the reference signal, the synchronization signal, and the broadcast channel signal to their respective subcarriers, performing inverse fast Fourier transformation to obtain a downlink baseband signal, and sending the downlink baseband signal out.

6. The downlink baseband signal generating method according to claim 5, wherein:

the mapping the downlink coded and modulated user signal that has undergone the multi-input multi-output precoding, the downlink control channel signal, the reference signal, the synchronization signal, and the broadcast channel signal to their respective subcarriers comprises;

mapping the downlink coded and modulated user signal that has undergone the multi-input multi-output precoding and the downlink control channel signal onto their respective subcarriers according to transmission resource indication information sent by the radio access network node, wherein the transmission resource indication information indicates subcarriers that correspond to the downlink coded and modulated user signal that has undergone the multi-input multi-output precoding and the downlink control channel signal respectively, and the transmission resource indication information is carried in the downlink control channel signal; and

mapping the reference signal, the synchronization signal, and the broadcast channel signal to their respective subcarriers according to a preset mapping rule, wherein the preset mapping rule is used to indicate subcarriers that correspond to the reference signal, the synchronization signal, and the broadcast channel signal respectively.

7. The downlink baseband signal generating method according to claim 5, further comprising:

receiving downlink coded and modulated user signals of other cells, wherein the downlink coded and modulated user signals of the other cells are forwarded by the radio access network node, and the specific cell and the other cells employ coordinated multi-point processing based on Network-MIMO on a physical layer; and

performing joint multi-input multi-output precoding on the downlink coded and modulated user signal of the specific cell and the downlink coded and modulated user signals of the other cells, mapping the downlink coded and modulated user signal of the specific cell and the downlink coded and modulated user signals of the other cells that have undergone the joint multi-input multi-output precoding signals, the downlink control channel signal, reference signal, synchronization signal, and broadcast channel signal onto their respective subcarriers, performing inverse fast Fourier transformation to obtain a downlink baseband signal, and sending the downlink baseband signal out.

8. A radio access network node comprising a computer processor and a non-transitory computer readable storage medium, at a distributed base station with remote radio, wherein the non-transitory computer readable storage medium comprising computer program codes which when executed by the computer processor cause the computer processor to execute the steps of:

performing channel coding and modulation on a downlink data stream of a user in a cell, obtaining a downlink coded and modulated user signal of the cell;

generating a downlink control channel signal according to physical-layer control information; and

forwarding a reference signal, a synchronization signal and a broadcast channel signal of the cell, and the downlink coded and modulated user signal and the downlink control channel signal to a corresponding remote radio unit, so that the corresponding remote radio unit performs multi-input multi-output precoding on the downlink coded and modulated user signal, maps the downlink coded and modulated user signal that has undergone the multi-input multi-output precoding, the downlink control channel signal, the reference signal, the synchronization signal, and the broadcast channel signal to their respective subcarriers, performs inverse fast Fourier transformation to obtain a downlink baseband signal, and sends the downlink baseband signal out.

9. The radio access network node according to claim 8, wherein the computer processor is specifically caused to execute the steps of:

forwarding the reference signal, the synchronization signal and the broadcast channel signal, and the downlink coded and modulated user signal and the downlink control channel signal to the corresponding remote radio unit according to a preset forwarding configuration list, wherein the preset forwarding configuration list is used to record a mapping relationship between user information and a remote radio unit identifier.

10. The radio access network node according to claim 8, wherein the computer processor is specifically caused to execute the steps of:

forwarding downlink coded and modulated user signals of other cells to the corresponding remote radio unit, so that the corresponding remote radio unit performs joint multi-input multi-output precoding on the downlink coded and modulated user signal of the cell and the downlink coded and modulated user signals of the other cells, maps the downlink coded and modulated user signal of the cell and the downlink coded and modulated user signals of the other cells that have undergone the joint multi-input multi-output precoding, the downlink control channel signal, the reference signal, the synchronization signal, and the broadcast channel signal onto their respective subcarriers, performs the inverse fast Fourier transformation to obtain a downlink baseband signal, and sends the downlink baseband signal out, wherein

the cell and the other cells employ coordinated multi-point processing based on Network-MIMO on a physical layer.

11. A remote radio unit comprising a computer processor and a non-transitory computer readable storage medium, at a distributed base station with remote radio, wherein the non-transitory computer readable storage medium comprising computer program codes which when executed by the computer processor cause the computer processor to execute the steps of:

receiving a downlink coded and modulated user signal and a downlink control channel signal of a specific cell, wherein the downlink coded and modulated user signal and the downlink control channel signal are forwarded by a radio access network node; and

performing multi-input multi-output precoding on the downlink coded and modulated user signal, wherein the downlink coded and modulated user signal is obtained after the radio access network node performs channel coding and modulation on a downlink data stream of a user in the specific cell, and the downlink control channel signal is generated by the radio access network node according to physical-layer control information;

receiving a reference signal, a synchronization signal, and a broadcast channel signal of a specific cell that are forwarded by the radio access network node; and

mapping the downlink coded and modulated user signal that has undergone the multi-input multi-output precoding, the downlink control channel signal, the reference signal, the synchronization signal, and the broadcast channel signal to their respective subcarriers;

performing inverse fast Fourier transformation on the signals mapped onto the subcarriers to obtain a downlink baseband signal; and

sending the downlink baseband signal out.

12. The remote radio unit according to claim 11, wherein the computer processor is specifically caused to execute the steps of:

receiving the reference signal, synchronization signal, and broadcast channel signal of the specific cell that are forwarded by the radio access network node; and

mapping the reference signal, the synchronization signal, and the broadcast channel signal onto their respective subcarriers according to a preset mapping rule, wherein the preset mapping rule is used to indicate the subcarriers that correspond to the reference signal, the synchronization signal, and the broadcast channel signal respectively; and

mapping the downlink coded and modulated user signal has undergone the multi-input multi-output precoding performed by the precoding module and the downlink control channel signal to their respective subcarriers according to transmission resource indication information sent by the radio access network node, wherein the transmission resource indication information is carried in the downlink control channel signal and is used to indicate the subcarriers that correspond to the downlink coded and modulated user signal that has undergone the multi-input multi-output precoding and the downlink control channel signal respectively.

13. The remote radio unit according to claim 11, wherein the computer processor is specifically caused to execute the steps of:

receiving downlink coded and modulated user signals of other cells, wherein the downlink coded and modulated user signals of the other cells are forwarded by the radio access network node; and

performing joint multi-input multi-output precoding on the downlink coded and modulated user signals of the other cells and the downlink coded and modulated user signal of the specific cell, wherein the specific cell and the other cells employ coordinated multi-point processing based on Network-MIMO on a physical layer; and

mapping the downlink coded and modulated user signal of the specific cell and the downlink coded and modulated user signals of the other cells that have undergone the joint multi-input multi-output precoding, the downlink control channel signal, the reference signal, the synchronization signal, and the broadcast channel signal to their respective subcarriers.