CN1661941A - Distributed base stations and data interactive method - Google Patents

Abstract

The invention discloses a distributed base station system, which includes a baseband and more than one remote radio unit, and a main multiplexing demultiplexing module and a standby multiplexing module for wavelength division multiplexing of multi-wavelength optical signals are arranged on the baseband side The demultiplexing module is equipped with an optical add-drop multiplexing module on the side of each remote radio unit, and connects the baseband and the remote radio unit through two optical fiber links in opposite directions to form a ring topology network of wavelength division multiplexing. At the same time, a data interaction method based on a distributed base station system is disclosed, and data transmission is performed simultaneously on eastbound and westbound optical fiber links of wavelength division multiplexing rings. It not only improves the data transmission bandwidth of each remote radio unit, but also simplifies the structural design of network equipment in each system. And by adopting a new self-healing switching protection mechanism, the reliability of the network is further improved while ensuring the normal data exchange between system devices.

Description

Distributed base station system and data interaction method

technical field

The invention relates to base station networking technology in a wireless communication system, in particular to a distributed base station networking system and a data interaction method.

Background technique

With the development of the third generation mobile communication (3G) technology, the design method of the base station tends to separate the baseband (BB, BaseBand) from the radio frequency. Remote Radio Unit (RRU) is a typical application under this design idea. It can solve problems such as difficulty in site selection of the equipment room and feeder cable loss, and improve the transmit power of the antenna port. But it also brings some new problems to be solved, one of the most important problems is the transmission networking problem between BB and RRU.

The interface signal between BB and RRU is an IQ signal with a relatively high rate. Generally, light is used as the medium for direct transmission. Since the IQ signal requires relatively small transmission delay, it is not suitable to use synchronous digital series (SDH) transmission.

See Figure 1, which is a schematic diagram of the distributed base station system structure of the ring networking scheme commonly used at present. Each node on the structural ring of this networking form has optical ports in two directions, and there are active optical ports on the BB Each RRU has an east optical port and a west optical port, the east optical port is directly or indirectly connected to the BB main optical port, and the west optical port is directly or indirectly connected to the BB backup optical port.

When the base station system shown in Figure 1 is working normally, in the downlink direction, the BB will multiplex the downlink interface data in the form of electrical interface signals sent to all RRUs on the ring using the frame structure and convert them into optical signals of a certain wavelength. RRU0 receives the downlink optical signal sent by BB through the eastbound optical port, restores the interface data in the form of electrical interface signal, intercepts the downlink interface data of this node for processing, and converts the remaining data into optical signal , and forward it to the next-level RRU through the west optical port, and the subsequent RRUs complete the same function in turn until RRUn receives the downlink interface data of this RRU from the east optical port.

In the uplink direction, after RRUn converts the uplink interface data into optical signals, it sends the uplink interface data through the eastbound optical port, and RRUn-1 receives the uplink interface data sent by RRUn through the westbound optical port, and inserts the uplink interface data of the node into the uplink interface data. The uplink interface data is sent through the eastbound optical port, and the subsequent RRUs perform the same function sequentially until the BB receives the uplink interface data of each RRU in the ring from the eastbound optical port.

When the system fails, for example: the optical fiber between RRUn-1 and RRUn is faulty, and the transmission of uplink and downlink interface data between BB and RRU0, ..., RRUm-1 remains unchanged, and each RRU still passes through the eastbound optical port Send and receive uplink and downlink interface data with the main optical port of BB; but the transmission of uplink and downlink interface data between BB and RRUm, ..., RRUn is the opposite of that before the failure, that is, each RRU sends and receives data through the west optical port and the backup optical port of BB Uplink and downlink interface data.

Since the existing ring networking scheme needs to design a relatively complex frame structure to multiplex the data of each RRU, each RRU also needs to complete the data frame-level add/drop and multiplex functions, so that each RRU interface The function design is very complicated; in addition, since all RRUs on the ring share the bandwidth of the same wavelength for data transmission and reception, the bandwidth of each RRU needs to be limited, causing network resources to be tight and affecting data transmission speed.

Contents of the invention

In view of this, the main purpose of the present invention is to provide a distributed base station system to solve the problems in the prior art that the functions of the RRU interface are too complicated and the data transmission bandwidth is limited.

Another object of the present invention is to provide a data interaction method based on the distributed base station system of the present invention, so as to realize normal data interaction between network devices in the system.

According to the first objective, a distributed base station system disclosed by the present invention includes a baseband and more than one remote radio unit, and the baseband and remote radio units are connected to form a ring topology network through two optical fiber links in opposite directions. The baseband side is equipped with a main multiplexing and demultiplexing module and a standby multiplexing and demultiplexing module for wavelength division multiplexing of multi-wavelength optical signals, and each remote radio unit is equipped with an eastbound optical port and a westbound optical port. optical add-drop multiplexing module;

The baseband converts the downlink electrical interface signal sent to each remote radio unit into optical signals of different wavelengths, and sends them to the main multiplexing and demultiplexing module and the standby multiplexing and demultiplexing module respectively;

The main multiplexing and demultiplexing module combines the downlink optical signals of different wavelengths and sends them step by step along an optical fiber link to the eastbound optical port of the optical add-drop multiplexing module on the side of each radio remote unit, and the standby multiplexing The demultiplexing module multiplexes the downlink optical signal and sends it step by step along another optical fiber link to the west optical port of the optical add-drop multiplexing module on the side of each radio remote unit;

Each optical add-drop multiplexing module takes out the optical signal of the local wavelength from the east optical port and the west optical port and sends it to the radio remote unit, and the radio remote unit converts the optical signal into an electrical interface signal;

Each radio remote unit converts the uplink electrical interface signal sent to the baseband into a local wavelength uplink optical signal, and sends it to the local optical add-drop multiplexing module;

The optical add-drop multiplexing module combines the local wavelength uplink optical signal with other wavelength optical signals received from the eastbound optical port, and then sends the uplink optical signal to the baseband through its own westbound optical port along an optical fiber link for standby multiplexing and demultiplexing The optical add-drop multiplexing module combines the uplink optical signal of the local wavelength with the other wavelength optical signals received from the westbound optical port, and then sends the uplink optical signal to the main baseband through its own eastbound optical port along another optical fiber link. Use multiplexing and demultiplexing modules;

The active multiplexing and demultiplexing module and the standby multiplexing and demultiplexing module respectively demultiplex the received uplink optical signals into optical signals of different wavelengths and send them to the baseband, and the baseband converts the optical signals into electrical interface signals.

The main and standby multiplexing and demultiplexing modules described in the system are multiplexing and demultiplexing modules for coarse wavelength division multiplexing or multiplexing and demultiplexing modules for dense wavelength division multiplexing.

The multiplexing and demultiplexing module described in the system is a multiplexing and demultiplexing device for coarse wavelength division multiplexing or a multiplexing and demultiplexing device for dense wavelength division multiplexing; the optical add-drop multiplexing module is Optical Add-Drop Multiplexer.

The main and standby multiplexing and demultiplexing modules of the system are arranged inside or outside the baseband; the optical add/drop multiplexing module is arranged inside or outside the remote radio unit.

The optical fiber link of the system further includes at least one optical relay unit.

According to the other objective, the present invention simultaneously discloses a data interaction method for a distributed base station system, which is applied to a distributed base station system with a ring topology connected by baseband and radio remote units through two optical fiber links in opposite directions. In the distributed base station networking system, a main multiplexing and demultiplexing module and a standby multiplexing and demultiplexing module for wavelength division multiplexing of multi-wavelength optical signals are arranged on the baseband side of the distributed base station networking system; Optical add-drop multiplexing module;

Allocate an optical wavelength for carrying data to each remote radio unit on each optical fiber link;

The data transmission process in the downlink direction of sending data from the baseband to the remote radio unit includes:

a) The baseband converts all the downlink electrical interface signals sent to the radio remote unit into the eastbound optical signal and the westbound optical signal of the corresponding assigned wavelength, and sends them to the main multiplexing and demultiplexing module and the standby multiplexing and demultiplexing module respectively. Reuse module;

b) The main multiplexing and demultiplexing module multiplexes all eastbound downstream optical signals and sends them to the eastbound optical port of the optical add-drop multiplexing module on the side of each radio remote unit on the ring network through a fiber link, The standby multiplexing and demultiplexing module multiplexes all westbound downstream optical signals and sends them to the westbound optical port of the optical add-drop multiplexer module on the side of each radio remote unit on the ring network through another optical fiber link;

c) The optical add-drop multiplexing module on the side of each radio remote unit takes out the downlink optical signals belonging to its own assigned wavelength from the downlink optical signals received by the eastbound optical port and westbound optical port, and sends them to the radio remote unit;

d) The radio remote unit selects one of the two downlink optical signals sent by the optical add-drop multiplexing module and converts one into an electrical interface signal for data processing;

The data transmission process in the uplink direction of the remote radio unit sending data to the baseband includes:

a') Each radio remote unit converts the uplink electrical interface signal that needs to be sent to the baseband into the corresponding assigned wavelength east uplink optical signal and west uplink optical signal and sends them to the local optical add-drop multiplexing module;

b') The optical add-drop multiplexing module combines and multiplexes the local westbound optical signal with the eastbound optical signal received from the eastbound optical port, and sends the westbound optical signal to the baseband through a fiber link from the westbound optical port. The standby multiplexing and demultiplexing module on the side sends the local eastbound optical signal and the westbound optical signal received from the westbound optical port to multiplex and multiplex, and passes through another optical fiber link from the eastbound optical port Send to the main multiplexing and demultiplexing module on the baseband side;

c') The main multiplexing and demultiplexing module and the backup multiplexing and demultiplexing module on the baseband side demultiplex the received eastbound optical signal and westbound optical signal respectively to obtain the remote radio frequency unit The uplink optical signal is sent to the baseband;

d') The baseband selects one of the two upstream optical signals of each radio remote unit sent by the main multiplexing and demultiplexing module and the standby multiplexing and demultiplexing module to convert it into an electrical interface signal for data processing.

The optical wavelength allocated to each remote radio unit in the method is the wavelength in the set of available wavelengths stipulated in the standard of the International Telecommunication Union.

In this method, the optical wavelengths allocated to the same remote radio unit for carrying data in the two optical fiber links are the same.

The multiplexing and demultiplexing module described in the method is a multiplexing and demultiplexing module for coarse wavelength division multiplexing or a multiplexing and demultiplexing module for dense wavelength division multiplexing.

The method between steps c) and d) further includes: the radio remote unit detects whether the two downlink optical signals sent by the add-drop multiplexing module are normal, and sends the detection result to the baseband;

Step d') specifically includes: the baseband detects whether the two upstream optical signals of each radio remote unit sent by the main multiplexing and demultiplexing module and the standby multiplexing and demultiplexing module are normal, and receives the signal sent by the radio remote unit. The baseband selects a group of normal uplink and downlink optical signals, converts the uplink optical signals into electrical interface signals and performs data processing, and sends an instruction message to the radio remote unit to notify it to receive the selected downlink light signal;

And the step d) specifically includes: the radio remote unit receives the instruction message sent by the baseband, selects the downlink optical signal specified in the message, converts it into an electrical interface signal, and performs data processing.

The method step d') described baseband selects a group of normal uplink and downlink optical signals and specifically includes:

d'1) If the two downlink optical signals of a remote radio unit are normal, and the two uplink optical signals of the remote radio unit on the baseband side are also normal, then the baseband selects a set of uplink and downlink interface data from it Uplink and downlink optical signals with minimum delay between them;

d'2) If one or more of the two downlink optical signals of a remote radio unit and the two uplink optical signals on the baseband side have one or more optical signals that are abnormal, the baseband will preferentially select one of the normal optical signals Uplink and downlink optical signals with opposite transmission paths.

In this method, according to the principle that the transmission path of the uplink and downlink optical signals is exactly the opposite, and the principle of preferentially selecting the minimum delay between the uplink and downlink interface data is set. In the case of different detection results, the baseband should choose the uplink optical signal and the radio remote unit should be selected. The correspondence table of the downlink optical signal is stored in the baseband;

Then in step d'1), the baseband selects a group of uplink and downlink optical signals with the smallest delay between the uplink and downlink interface data. A set of uplink and downlink optical signals, baseband measurement Under this option, the interface data delay value between the baseband and the remote radio unit uplink and downlink optical signals;

The baseband restores the previous downlink optical signal and turns off the other downlink optical signal. According to the corresponding table, select a set of uplink and downlink optical signals corresponding to this case. Under this selection of baseband measurement, the uplink and downlink of the baseband radio remote unit Interface data delay value between optical signals;

The baseband compares the measured interface data delay values under the two options, and selects a group of uplink and downlink optical signals with a smaller delay value;

Step d'2) The baseband selects a group of uplink and downlink optical signals with opposite uplink and downlink transmission paths in the normal optical signal. The process specifically includes: the baseband searches in the corresponding table and selects a group of uplink and downlink optical signal.

In this method, the radio remote unit sends the detection result to the baseband through the network physical layer; the baseband sends an instruction message to the radio remote unit through the network physical layer.

It can be seen from the above that the distributed base station system and its data interaction method provided by the present invention use wavelength division multiplexing technology to set a main multiplexing system for multi-wavelength optical signal wavelength division multiplexing on the baseband side. Demultiplexing module and standby multiplexing demultiplexing module, an optical add-drop multiplexing module is installed on the side of each remote radio unit, and the BB and RRU are connected into a wavelength division multiplexing through two optical fiber links in opposite directions. The ring networking structure greatly improves the data transmission bandwidth of each RRU, and at the same time simplifies the structural design of the network equipment in each system, reduces the cost of the network equipment, and improves the data transmission speed. In the process of data interaction, using the characteristics of the ring network technology, data transmission is carried out simultaneously on the eastbound and westbound optical fiber links of the WDM ring, and by adopting a new self-healing switching protection mechanism, between the guarantee system equipment At the same time of normal data exchange, the reliability of the network is further improved.

Description of drawings

FIG. 1 is a schematic diagram of an existing distributed base station system adopting a ring networking structure;

FIG. 2 is a schematic structural diagram of a distributed base station system according to an embodiment of the present invention;

3 is a schematic diagram of data transmission and reception of OADM on the RRU side in an embodiment of the present invention;

Fig. 4 is a schematic diagram of optical fiber link self-healing switching when the second case occurs in the embodiment of the present invention;

Fig. 5 is a schematic diagram of fiber link self-healing switching when the third case occurs in the embodiment of the present invention;

Fig. 6 is a schematic diagram of optical fiber link self-healing switching when the fourth situation occurs in the embodiment of the present invention;

Fig. 7 is a schematic diagram of optical fiber link self-healing switching when the fifth situation occurs in the embodiment of the present invention;

Fig. 8 is a schematic diagram of optical fiber link self-healing switching when the sixth situation occurs in the embodiment of the present invention;

FIG. 9 is a schematic diagram of fiber link self-healing switching when the seventh situation occurs according to the embodiment of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

The scheme of the present invention adopts a ring networking structure, utilizes wavelength division multiplexing technology, and sets an active multiplexing and demultiplexing module and a standby multiplexing and demultiplexing module for wavelength division multiplexing of multi-wavelength optical signals on the baseband side, and each An optical add-drop multiplexing module is arranged on the side of each radio remote unit, and the BB and the RRU are connected to form a wavelength division multiplexing ring through two optical fiber links in opposite directions. And by rationally arranging the data transmission path between the BB and the RRU, the wavelength used for data transmission by each RRU is reasonably allocated. While solving the problem of limited data transmission bandwidth, the structure of each network device in the system is simplified, and the reliability of the network is guaranteed by using the ring network technology and the new self-healing switching protection mechanism.

Because the Coarse Wavelength Division Multiplexing (CWDM, Coarse Wavelength Division Multiplexing) technology is a kind of optical transmission technology widely used in the near future, it can improve the utilization rate of the optical fiber at a relatively low cost, so the CWDM ring network technology is used in this embodiment Networking of RRUs.

The structure of the distributed base station system in this embodiment is shown in FIG. 2 . On the BB side, there are two multiplexer/demultiplexers (MUX/DMUX) for multiplexing and demultiplexing optical signals of each wavelength, among which MUX/DMUX0 is the active module and MUX/DMUX1 is the standby module . On the RRU side, an optical add-drop multiplexer (OADM) is provided to realize the optical add-drop multiplex function of the relevant wavelength. There are two pairs of optical ports on each OADM, one pair of optical ports is directly or indirectly connected to MUX/DMUX0, mainly used for data transmission and reception with MUX/DMUX0, and the other pair of optical ports is directly or indirectly connected to MUX/DMUX1, mainly Used to send and receive data with MUX/DMUX1. MUX/DMUX0, MUX/DMUX1 and the two pairs of optical ports of the OADM on the RRU side are connected through two optical fiber links in the clockwise direction represented by the solid line and in the counterclockwise direction represented by the dotted line in Figure 2.

In the embodiment of the present invention, it is stipulated that the data transmission direction from BB to RRU is the downlink direction; the data transmission direction from RRU to BB is the uplink direction. The direction in which OADM is directly or indirectly connected to the active MUX/DMUX is east; the direction in which OADM is directly or indirectly connected to standby MUX/DMUX is west. The pair of optical ports directly or indirectly connected to MUX/DMUX0 on the OADM are eastbound optical ports; the pair of optical ports directly or indirectly connected to MUX/DMUX1 are westbound ports.

The electrical interface signals for realizing data interaction between BB and RRU0, RRU1, ... RRUn in the distributed base station system are IF0, IF1, ..., IFn respectively. Among them, IF0 is used for RRU0, IF1 is used for RRU1, and so on, IFn is used for RRUn. When it is necessary to perform data transmission on the CWDM ring, the downlink and uplink electrical interface signals IF between the BB and RRU to be sent are first converted into optical signals of corresponding wavelengths on the BB and RRU sides; The optical signal is recovered out of the IF.

Therefore, for each RRU, two wavelengths are assigned to it from the available wavelength set {λ0,λ1,...,λn} of the CWDM ring network specified in the International Telecommunications Union (ITU-T) standard, and the RRU uses one of them One wavelength is used for eastbound reception and westbound transmission of transmission data carried in the clockwise optical fiber link, and the other wavelength is used for westbound reception and eastbound transmission of transmission data carried in the counterclockwise optical fiber link.

The specific allocation of each RRU wavelength in this embodiment is shown in Table 1: RRU0 RRU1 ... RRUn RRU receives eastbound and sends westbound λ0' λ1' ... λn' The RRU westbound receives and eastbound sends λ0" λ1" ... λn"

Table 1

Since the RRU's eastbound westbound transmission and the RRU's westbound eastbound transmission are transmitted through different optical fiber links, the same wavelength can be allocated for the same RRU's eastbound westbound transmission and westbound eastbound transmission, that is, In 1, for any RRUx (x=0, 1, ..., n), λx'=λx" can be set. And the available wavelength set is in one-to-one correspondence with the RRU eastbound westbound transmission wavelength set, and the available wavelength set is related to the RRU There is a one-to-one correspondence between westbound and eastbound transmission wavelength sets.

For the downlink direction of data: on the BB side, according to the wavelength allocation principle in Table 1, the BB simultaneously converts the electrical interface signal IF downlink to each RRU into two downlink optical signals with wavelengths λ' and λ", and sends them to Enter MUX/DMUX0 and MUX/DMUX1.

Taking the xth RRU as an example, a) BB simultaneously converts the electrical interface signal IFx downlinked to RRUx (x=0, 1, ..., n) into two downlink optical signals with wavelengths λx' and λx", respectively Feed to MUX/DMUX0 and MUX/DMUX1.

b) MUX/DMUX0 as the main module combines all the east-bound optical signals λ0', λ1', ..., λn' and sends them to the clockwise optical fiber link of the CWDM ring; MUX/DMUX0 as the backup module DMUX1 multiplexes all westbound optical signals λ0", λ1", ..., λn" to the counterclockwise optical fiber link of the CWDM ring.

c) When the downlink optical signal reaches the RRUx side, as shown in Figure 3, the OADMx on the RRUx side takes out its own downlink optical signal λx' from the east optical port, and takes out its own downlink optical signal λx" from the west into RRUx.

d) RRUx selects one downlink optical signal from λx’ and λx” for photoelectric conversion, and restores the IFx electrical interface signal.

For the uplink direction of data: a') On the RRUx side, the RRUx converts the uplink electrical interface signal IFx sent to BB into two uplink optical signals with wavelengths λx' and λx" and sends them to OADMx.

b') As shown in Figure 3, OADMx combines the uplink optical signal λx" with all the optical signals λ0", λ1", ..., λx-1", λx+ received from the local westbound optical port except the downlink λx" 1", ..., λn" are multiplexed and sent to the counterclockwise optical fiber link of the CWDM ring from the east optical port; at the same time, OADMx combines the uplink optical signal λx' with all the signals received from the east optical port except λx' Optical signals of wavelengths λ0', λ1', ..., λx-1', λx+1', ..., λn' are multiplexed and sent to the clockwise optical fiber link of the CWDM ring from the westbound optical port.

c') When the uplink optical signal reaches the BB side, MUX/DMUX0 decomposes the uplink optical signal received from the counterclockwise optical fiber link into n+1 channels of light with wavelengths λ0", λ1", ..., λn" The signal is sent to BB; MUX/DMUX1 decomposes the uplink optical signal received from the clockwise optical fiber link into n+1 optical signals with wavelengths λ0', λ1', ..., λn' and sends them to BB.

d') BB selects one of each pair of uplink optical signals λx" and λx' for photoelectric conversion, and recovers the uplink IFx electrical interface signal of RRUx corresponding to the signal for processing.

During the working process of the distributed base station networking system of the present invention described above, the BB needs to select one optical signal from the two upstream optical signals λx' and λx" of each RRUx to restore the uplink electrical interface signal IFx; each RRUx It is necessary to select one optical signal from the two downstream optical signals λx' and λx" to restore to the downstream electrical interface signal IFx.

In order to ensure the best transmission effect, this embodiment requires BB and RRU to follow the following two constraints when selecting optical signals:

1. The transmission delay of uplink interface data between BB and RRUx (x=0, 1, ..., n) is as consistent as possible with the transmission delay of downlink interface data between BB and RRUx, showing that the transmission path is just opposite.

2. The transmission delay of uplink interface data between BB and RRUx (x=0, 1, ..., n) and the transmission delay of downlink interface data between BB and RRU are as small as possible.

The priority of condition 1 is higher than that of condition 2, that is, condition 1 must be satisfied first, and then condition 2 must be satisfied on the basis of condition 1.

According to the above two constraints, the optical signal selection scheme of BB and RRU formulated in this embodiment is shown in Table 2. BB detects two uplink optical signals RRUx detects two downlink optical signals Uplink optical signal selected by BB Downlink optical signal selected by RRUx λ _x ' λ _x " λ _x ' λ _x " 1 normal normal normal normal Choose the path of least delay 2 Fault normal normal -- λ _x " λ _x ' 3 -- normal normal Fault λ _x " λ _x ' 4 normal Fault -- normal λ _x ' λ _x " 5 normal -- Fault normal λ _x ' λ _x " 6 normal Fault normal Fault λ _x ' λ _x ' 7 Fault normal Fault normal λ _x " λ _x "

Table 2

And save the optical signal selection scheme shown in Table 2 in the BB, when the BB and RRU select the optical signal, specifically include the following process:

On the BB side, the BB detects whether λ0', λ1', ..., λn' and λ0", λ1", ..., λn" of the uplink optical signal are normal.

On the RRU side, each RRUx detects whether the downlink optical signals λx' and λx" are normal, and reports the detection results to the BB through the physical layer or other methods.

The processing done by BB includes the following 7 situations according to Table 2:

1. If the BB detects that the uplink optical signals λx' and λx" of the RRUx are normal, and the RRUx detects that the downlink optical signals λx' and λx" are also normal, then the BB and the RRUx select a set of transmission delay between the uplink and downlink interface data. When the smallest transmission path, the specific process includes:

a. BB turns off the downlink λx" optical signal. According to the third optical signal selection principle in Table 2, BB selects the uplink λx" optical signal, and RRUx selects the downlink λx' optical signal. BB measures the uplink and downlink between BB and RRUx Data transmission delay, set this value as T0.

b. BB recovers the downlink λx" optical signal, and then BB turns off the downlink λx' optical signal. According to the fifth optical signal selection principle in Table 2, BB selects the uplink λx' optical signal, RRUx selects the downlink λx" optical signal, and BB measures Figure out the transmission delay from BB to RRUx, set this value as T1, and BB restores the downlink λx' optical signal.

c. BB compares T0 and T1. When T0≤T1, BB selects the uplink λx" optical signal, and BB sends an instruction message to RRUx through the physical layer to inform RRUx to select the downlink λx' optical signal; when T0>T1, BB The uplink λx' optical signal is selected, and the BB sends an instruction message to the RRUx through the physical layer to notify the RRUx to select the downlink λx" optical signal.

2. As shown in Figure 4, the BB detects that the uplink optical signal λx” is normal, but the uplink optical signal λx’ is faulty, and the RRUx detects that the downlink optical signal λx’ is normal. After receiving the detection result reported by the RRU, the BB ignores the downlink optical signal Whether λx" is normal, by looking up Table 2, the BB will select the uplink optical signal λx", and send an instruction message to the RRUx to inform the RRUx to select the uplink optical signal λx'.

3. As shown in Figure 5, the RRUx detects that the downlink optical signal λx' is normal, but the downlink optical signal λx" is faulty, and the BB detects that the uplink optical signal λx" is normal. After receiving the detection result reported by the RRU, the BB ignores the uplink optical signal Whether λx' is normal, by looking up Table 2, the BB selects the uplink optical signal λx", and sends an instruction message to the RRUx to inform the RRUx to select the uplink optical signal λx'.

4. As shown in Figure 6, the BB detects that the uplink optical signal λx' is normal, but the uplink optical signal λx" is faulty, and the RRUx detects that the downlink optical signal λx" is normal. After receiving the detection result reported by the RRU, the BB ignores the downlink optical signal Whether λx' is normal, by looking up Table 2, BB selects the uplink optical signal λx', and sends an instruction message to RRUx to inform RRUx to select the uplink optical signal λx".

5. As shown in Figure 7, RRUx detects that the downlink optical signal λx" is normal, but the downlink optical signal λx' is faulty, and BB detects that the uplink optical signal λx' is normal. After receiving the detection result reported by RRU, BB checks Table 2 , regardless of whether the uplink optical signal λx" is normal or not, the BB selects the uplink optical signal λx', and sends an instruction message to the RRUx to inform the RRUx to select the uplink optical signal λx".

6. As shown in Figure 8, BB detects that the uplink optical signal λx' is normal, but the uplink optical signal λx" is faulty, RRUx detects that the downlink optical signal λx' is normal but the downlink optical signal λx" is faulty, and BB receives the report from the RRU After the detection result, by looking up Table 2, the BB selects the uplink optical signal λx', and sends an instruction message to the RRUx to notify the RRUx to select the uplink optical signal λx'.

7. As shown in Figure 9, BB detects that the uplink optical signal λx" is normal, but the uplink optical signal λx' is faulty, RRUx detects that the downlink optical signal λx" is normal, but the downlink optical signal λx' is faulty, and BB receives the report from the RRU After the detection result, by looking up Table 2, the BB selects the uplink optical signal λx", and sends an instruction message to the RRUx to notify the RRUx to select the uplink optical signal λx".

In addition, in order to increase the data transmission distance, an optical relay unit such as an optical power amplifier can be added to the optical fiber link. In the case where there are many RRU sites in the distributed base station, dense wavelength division multiplexing (DWDM) MUX/DMUX can be used on the BB side, and the CWDM technology in the above embodiment can be replaced by the DWDM technology capable of multiplexing more wavelengths. The multiplexing and demultiplexing module of the present invention can be arranged inside or outside the baseband; the optical add/drop multiplexing module can also be arranged inside or outside the remote radio unit.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (13)

1. A distributed base station system, including a baseband and more than one remote radio unit, the baseband and radio remote units are connected to form a ring topology network through two optical fiber links in opposite directions, characterized in that the baseband side is set There are main multiplexing and demultiplexing modules and standby multiplexing and demultiplexing modules for wavelength division multiplexing of multi-wavelength optical signals, and an optical division including eastbound optical ports and westbound optical ports is arranged on the side of each radio remote unit. plug-in multiplexing module; The baseband converts the downlink electrical interface signal sent to each remote radio unit into optical signals of different wavelengths, and sends them to the main multiplexing and demultiplexing module and the standby multiplexing and demultiplexing module respectively; The main multiplexing and demultiplexing module combines the downlink optical signals of different wavelengths and sends them step by step along an optical fiber link to the eastbound optical port of the optical add-drop multiplexing module on the side of each radio remote unit, and the standby multiplexing The demultiplexing module multiplexes the downlink optical signal and sends it step by step along another optical fiber link to the west optical port of the optical add-drop multiplexing module on the side of each radio remote unit; Each optical add-drop multiplexing module takes out the optical signal of the local wavelength from the east optical port and the west optical port and sends it to the radio remote unit, and the radio remote unit converts the optical signal into an electrical interface signal; Each radio remote unit converts the uplink electrical interface signal sent to the baseband into a local wavelength uplink optical signal, and sends it to the local optical add-drop multiplexing module; The optical add-drop multiplexing module combines the local wavelength uplink optical signal with other wavelength optical signals received from the eastbound optical port, and then sends the uplink optical signal to the baseband through its own westbound optical port along an optical fiber link for standby multiplexing and demultiplexing The optical add-drop multiplexing module combines the uplink optical signal of the local wavelength with the other wavelength optical signals received from the westbound optical port, and then sends the uplink optical signal to the main baseband through its own eastbound optical port along another optical fiber link. Use multiplexing and demultiplexing modules; The active multiplexing and demultiplexing module and the standby multiplexing and demultiplexing module respectively demultiplex the received uplink optical signals into optical signals of different wavelengths and send them to the baseband, and the baseband converts the optical signals into electrical interface signals. 2. The system according to claim 1, characterized in that, the main and standby multiplexing and demultiplexing modules are multiplexing and demultiplexing modules for coarse wavelength division multiplexing or for dense wavelength division multiplexing The multiplexing and demultiplexing module used. 3. The system according to claim 1, wherein the multiplexing and demultiplexing module is a multiplexing and demultiplexing device for coarse wavelength division multiplexing or a multiplexing and demultiplexing device for dense wavelength division multiplexing A multiplexer; the optical add-drop multiplexer module is an optical add-drop multiplexer. 4. The system according to claim 1, characterized in that, the main and standby multiplexing and demultiplexing modules are set inside or outside the baseband; the optical add-drop multiplexing module is set inside or outside the remote radio unit external. 5. The system according to claim 1, wherein the optical fiber link further comprises at least one optical relay unit. 6. A data interaction method for a distributed base station system, which is applied to a distributed base station system with a ring topology connected by baseband and radio remote units through two optical fiber links in opposite directions. It is characterized in that, in the distributed The baseband side of the base station networking system is equipped with a main multiplexing and demultiplexing module and a standby multiplexing and demultiplexing module for wavelength division multiplexing of multi-wavelength optical signals; with modules; Allocate an optical wavelength for carrying data to each remote radio unit on each optical fiber link; The data transmission process in the downlink direction of sending data from the baseband to the remote radio unit includes: a) The baseband converts all the downlink electrical interface signals sent to the radio remote unit into the eastbound optical signal and the westbound optical signal of the corresponding assigned wavelength, and sends them to the main multiplexing and demultiplexing module and the standby multiplexing and demultiplexing module respectively. Reuse module; b) The main multiplexing and demultiplexing module multiplexes all eastbound downstream optical signals and sends them to the eastbound optical port of the optical add-drop multiplexing module on the side of each radio remote unit on the ring network through a fiber link, The standby multiplexing and demultiplexing module multiplexes all westbound downstream optical signals and sends them to the westbound optical port of the optical add-drop multiplexer module on the side of each radio remote unit on the ring network through another optical fiber link; c) The optical add-drop multiplexing module on the side of each radio remote unit takes out the downlink optical signals belonging to its own assigned wavelength from the downlink optical signals received by the eastbound optical port and westbound optical port, and sends them to the radio remote unit; d) The radio remote unit selects one of the two downlink optical signals sent by the optical add-drop multiplexing module and converts one into an electrical interface signal for data processing; The data transmission process in the uplink direction of the remote radio unit sending data to the baseband includes: a') Each radio remote unit converts the uplink electrical interface signal that needs to be sent to the baseband into the corresponding assigned wavelength east uplink optical signal and west uplink optical signal and sends them to the local optical add-drop multiplexing module; b') The optical add-drop multiplexing module combines and multiplexes the local westbound optical signal with the eastbound optical signal received from the eastbound optical port, and sends the westbound optical signal to the baseband through a fiber link from the westbound optical port. The standby multiplexing and demultiplexing module on the side sends the local eastbound optical signal and the westbound optical signal received from the westbound optical port to multiplex and multiplex, and passes through another optical fiber link from the eastbound optical port Send to the main multiplexing and demultiplexing module on the baseband side; c') The main multiplexing and demultiplexing module and the backup multiplexing and demultiplexing module on the baseband side demultiplex the received eastbound optical signal and westbound optical signal respectively to obtain the remote radio frequency unit The uplink optical signal is sent to the baseband; d') The baseband selects one of the two upstream optical signals of each radio remote unit sent by the main multiplexing and demultiplexing module and the standby multiplexing and demultiplexing module to convert it into an electrical interface signal for data processing. 7. The method according to claim 6, characterized in that the optical wavelength allocated to each remote radio unit is a wavelength in the set of available wavelengths specified in the International Telecommunication Union standard. 8. The method according to claim 6, characterized in that the optical wavelengths allocated to the same remote radio unit for carrying data in the two optical fiber links are the same. 9. The method according to claim 6, wherein the multiplexing and demultiplexing module is a multiplexing and demultiplexing module for coarse wavelength division multiplexing or a multiplexing and demultiplexing module for dense wavelength division multiplexing Reuse modules. 10. The method according to claim 6, characterized in that, between steps c) and d), further comprising: the radio remote unit detects whether the two downlink optical signals sent by the add-drop multiplexing module are normal, and sends the detection result send to baseband; Step d') specifically includes: the baseband detects whether the two upstream optical signals of each radio remote unit sent by the main multiplexing and demultiplexing module and the standby multiplexing and demultiplexing module are normal, and receives the signal sent by the radio remote unit. The baseband selects a group of normal uplink and downlink optical signals, converts the uplink optical signals into electrical interface signals and performs data processing, and sends an instruction message to the radio remote unit to notify it to receive the selected downlink light signal; And the step d) specifically includes: the radio remote unit receives the instruction message sent by the baseband, selects the downlink optical signal specified in the message, converts it into an electrical interface signal, and performs data processing. 11. The method according to claim 10, wherein the baseband selection of a set of normal uplink and downlink optical signals in step d') specifically includes: d'1) If the two downlink optical signals of a remote radio unit are normal, and the two uplink optical signals of the remote radio unit on the baseband side are also normal, then the baseband selects a set of uplink and downlink interface data from it Uplink and downlink optical signals with minimum delay between them; d'2) If one or more of the two downlink optical signals of a remote radio unit and the two uplink optical signals on the baseband side have one or more optical signals that are abnormal, the baseband will preferentially select one of the normal optical signals Uplink and downlink optical signals with opposite transmission paths. 12. The method according to claim 11, characterized in that, in the case of setting a different detection result according to the principle that the uplink and downlink optical signal transmission paths are just opposite, and the minimum delay between the uplink and downlink interface data is selected first, the baseband The corresponding table of the uplink optical signal to be selected and the downlink optical signal to be selected by the remote radio unit is stored in the baseband; Then in step d'1), the baseband selects a group of uplink and downlink optical signals with the smallest delay between the uplink and downlink interface data. A set of uplink and downlink optical signals, baseband measurement Under this option, the interface data delay value between the baseband and the remote radio unit uplink and downlink optical signals; The baseband restores the previous downlink optical signal and turns off the other downlink optical signal. According to the corresponding table, select a set of uplink and downlink optical signals corresponding to this case. Under this selection of baseband measurement, the uplink and downlink of the baseband radio remote unit Interface data delay value between optical signals; The baseband compares the measured interface data delay values under the two options, and selects a group of uplink and downlink optical signals with a smaller delay value; Step d'2) The baseband selects a group of uplink and downlink optical signals with opposite uplink and downlink transmission paths in the normal optical signal. The process specifically includes: the baseband searches in the corresponding table and selects a group of uplink and downlink optical signal. 13. The method according to claim 10, wherein the remote radio unit sends the detection result to the baseband through the network physical layer; and the baseband sends an instruction message to the remote radio unit through the network physical layer.

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