CN115190494B

CN115190494B - Wireless signal forwarding method and device based on PON (Passive optical network)

Info

Publication number: CN115190494B
Application number: CN202211098975.3A
Authority: CN
Inventors: 庞军
Original assignee: Shenzhen Fanweitai Technology Service Co ltd
Current assignee: Guangdong Broadradio Communication Technology Co Ltd
Priority date: 2022-09-09
Filing date: 2022-09-09
Publication date: 2022-12-02
Anticipated expiration: 2042-09-09
Also published as: CN115190494A

Abstract

The invention belongs to the field of wireless communication, in particular to a wireless signal forwarding method and a wireless signal forwarding device based on a PON (passive optical network), wherein the method comprises the following steps of: the method comprises the following steps: the system comprises a BBU unit, a HUB unit and an RU unit; the BBU equipment and the OLT equipment are co-located, the HUB unit and the second-level light splitting are co-located, and the RU unit and the ONU unit are co-located; the BBU unit returns back through the IPRAN resource of the machine room where the OLT equipment is located, and connection with a core network is established; point-to-multipoint transmission is used between the HUB and the BBU; point-to-point transmission is used between the RU and the HUB; the RU unit and the ONU unit divide the optical signals into two paths by using WDM and respectively send the two paths of optical signals to the RU unit and the ONU unit, and the RU unit changes the baseband signals into wireless signals so as to complete the coverage of the wireless signals. The invention provides a network transmission system which does not need a security gateway, does not need a special 4G/5G baseband chip for a covering unit, does not need to lay cables again, and can match with ONU one-to-one or one-to-many and has wide signal covering range.

Description

Wireless signal forwarding method and device based on PON (Passive optical network)

Technical Field

The present invention relates to the field of wireless communications, and in particular, to a PON network-based wireless signal forwarding method and apparatus.

Background

The 4G/5G signal wireless coverage methods in the prior art mainly include the following three methods:

(1) The light cat adds integrative skin station and realizes family or enterprise 4G wireless coverage, as shown in fig. 1: and the call back to the core network in a PTN + VLAN or IPsec mode is supported, and the opening of the 4G cell is completed. In this mode, a home or an enterprise is used as a unit to exclusively share an LTE cell. The mode is characterized in that the LTE cell opening can be completed by using the optical fiber of the original PON (Passive optical Network) Network without secondary wiring construction, property coordination and the like. The method provides the home or enterprise broadband for the user, and simultaneously provides the LTE service with high quality. The method is mainly used for family scenes or small and micro enterprise scenes, can quickly improve the indoor coverage quality of wireless signals and improve user experience, and can shunt the flow of macro stations and relieve the capacity expansion pressure of macro networks.

(2) As shown in fig. 2, the extended pico-base station is an evolution form of an integrated pico-base station, and adopts a digital technology, and a micro-power indoor coverage scheme based on transmission and distribution of optical fiber or network cable bearing wireless signals. The method is mainly used for low-capacity indoor scenes and is one of indoor coverage enhancement schemes. An extended pico-station, similar to watson, includes a base unit (BBU), an Extended Unit (EU), and a Radio Unit (RU). The extended pico-base station can conveniently and simultaneously support the coverage of 4G and 5G wireless signals by extending the functions of the host unit, and meanwhile, the coverage unit can realize lower cost;

(3) The wireless coverage is realized in the PON network secondary split forward, as shown in fig. 3: the BBU carries out feedback through a broadband interface of one ONU unit after secondary light splitting, and establishes connection with a core network; service data is processed by a BBU baseband and is combined with an optical signal of PON secondary light splitting through a fronthaul interface optical signal thereof and then is transmitted to the RONU unit; the combined optical signal is transmitted to a user residence through a single optical fiber and then is divided into two optical signals by using an optical splitter, and the two optical signals are respectively sent to the RU unit and the ONU unit, and the RU unit changes the baseband signal into a wireless signal to complete wireless signal coverage.

The three communication methods have the following disadvantages: the inside of the optical modem integrated leather station is provided with a baseband chip, so that the equipment cost and the power consumption are high; the base stations are more, so that the adjacent cell relation is complex, the adjacent cell interference is serious, the core network parameters are more, the opening and the management maintenance are complex, and the 5G realization cost is high; the expansion type pico-station needs to be re-wired and constructed, the manufacturing cost is high, and the ONU units return and occupy the current broadband flow.

Disclosure of Invention

The invention provides a wireless signal forwarding method based on a PON (passive optical network), which is characterized by comprising the following steps: comprises a BBU unit and an RU unit; wherein, the BBU equipment and the OLT equipment are co-located, and the RU unit and the ONU unit are co-located; the BBU unit returns back through the IPRAN resource of the machine room where the OLT equipment is located, and connection with a core network is established; the RU unit and the ONU unit are divided into two optical signals by using WDM, and the two optical signals are respectively sent to the RU unit and the ONU unit, and the RU unit changes the baseband signal into a wireless signal so as to complete the coverage of the wireless signal.

Wherein, the preferred scheme is as follows: further comprising: a HUB unit having an upstream interface C and an extended optical port; the BBU unit returns back through the IPRAN resource of the machine room where the OLT equipment is located, and connection with a core network is established; service data is processed by a BBU unit baseband and is transmitted to a second-level light splitting box through a two-level light splitting network after an optical signal passing through a fronthaul interface of the BBU baseband and an optical signal passing through a PON port of OLT equipment are subjected to wavelength division multiplexing; the surplus optical fiber after the second-stage light splitting is directly connected to an uplink port C of the HUB, and the HUB unit distributes and processes the baseband signals from the BBU and transmits the baseband signals to a plurality of extended optical ports of the HUB unit; the signal of the expansion optical port and the optical signal of the PON port after the second-stage light splitting are combined with the WDM wavelength according to requirements, then the signals are transmitted to a user through a single optical fiber, the signals are divided into two paths of optical signals through the optical splitter, the two paths of optical signals are respectively sent to the RU unit and the ONU unit, and the RU unit changes the baseband signals into wireless signals so as to complete the coverage of the wireless signals.

Wherein, the preferred scheme is as follows: the BBU unit supports point-to-multipoint transmission to the HUB unit, the BBU unit uses laser wavelength lambda 7 and lambda 8 to carry out forward transmission, time division CPRI forward transmission is adopted between the BBU unit and the HUB unit, wherein a downlink adopts a broadcast mode, an uplink adopts a time division mode, each HUB carries out time division uplink transmission, the wavelength of the downlink comprises lambda 1, lambda 5 and lambda 7, the wavelength of the uplink comprises lambda 2, lambda 6 and lambda 8, wherein lambda 1, lambda 2, lambda 5 and lambda 6 are respectively used by GPON and XGPON OLT equipment, and the wavelengths are combined into one fiber to be connected to one port of the WDM; the wavelengths λ 7 and λ 8 are used wavelengths of BBU units of radio signals, and are connected to a wavelength selection channel of WDM using one fiber.

Wherein, the preferred scheme is as follows: the BBU unit determines the number of directly-connected HUBs of the BBU unit according to the maximum transmission bandwidth supported by the fronthaul optical interface and the uplink transmission bandwidth requirement of the RU unit, and the formula for calculating the number NTh of the HUBs is as follows: when BWTH/BWRU-INT (BWTH/BWRU) <1% is more than or equal to 0, NTh = INT (BWTH/BWRU) -1; when BWTH ÷ BWRU-INT (BWTH ÷ BWRU) is greater than or equal to 1%, NTh = INT (BWTH ÷ BWRU), wherein the forward bandwidth: BWTH; RU uplink bandwidth: BWRU; INT is a rounding function.

The invention relates to a wireless signal forwarding device based on a PON (passive optical network), which is characterized in that: the system comprises a BBU and an RU unit, wherein the BBU unit and an OLT device are co-located, and the RU unit and an ONU unit are co-located; the BBU unit returns back through an IPRAN resource of a machine room where OLT equipment is located, and connection with a core network is established; the RU unit and the ONU unit are divided into two optical signals by using an optical splitter and WDM, and the two optical signals are respectively sent to the RU unit and the ONU unit.

Wherein, the preferred scheme is as follows: the system also comprises a HUB unit, wherein the HUB unit comprises a time-sharing CPRI interface connection which uses redundant optical fibers after secondary light splitting as an uplink port C and a BBU unit, and a plurality of expansion optical ports, wherein the BBU equipment and the OLT equipment are co-located, and the HUB unit and the secondary optical splitter are co-located; and the BBU unit and the HUB unit are connected by adopting a time division CPRI forward transmission connection mode.

Wherein, the preferred scheme is as follows: the upper connection port C of the HUB unit is a CPRI interface, and the extension optical port of the HUB unit is a point-to-point CPRI interface.

Wherein, the preferred scheme is as follows: the BBU unit is integrated in the OLT equipment; the optical splitter and the WDM optical splitting unit can also be independently taken as one component and are not arranged in the RU unit or the ONU unit equipment.

Compared with the prior art, the invention has the beneficial effects that:

1. the home unit does not need a special 4G/5G baseband chip, and equipment for realizing 4G/5G wireless coverage is simpler, has smaller power consumption and lower cost, and is convenient to popularize; meanwhile, the required core network parameters are few, the network is plugged and used in the home, and the workload of opening, managing and maintaining is small.

2. The RU unit of the invention is installed and used with the existing broadband terminal to enter the home by the rubber-insulated wire in the prior art, and the cable does not need to be laid again, thereby reducing the construction difficulty.

3. The existing PON network can be fully utilized, 4G/5G wireless coverage can be quickly realized in a place with the PON network, and compared with a 4G/5G newly-built expansion type leather station, the wireless coverage system has the advantages of quick and simple construction and low overall network manufacturing cost.

4. The invention has the advantages of high quality of wireless signals and small interference.

5. Because the BBU unit is directly integrated in the OLT machine room, the IPRAN can be directly used for returning, and compared with an integrated home-level or enterprise-level pico station, the IPRAN does not need to use a security gateway and does not occupy broadband flow.

Drawings

Fig. 1 is a schematic diagram of a 4G wireless coverage method for a home or an enterprise implemented by an optical modem and an integrated leather station in the prior art;

FIG. 2 is a schematic diagram of a method for implementing enterprise scenario 4G/5G wireless coverage in an extended pico-station in the prior art;

fig. 3 is a schematic diagram illustrating a method for implementing wireless coverage in PON network secondary split forward in the prior art;

fig. 4 is a schematic diagram of a first embodiment of a PON network-based wireless signal forwarding apparatus according to the present invention;

fig. 5 is a schematic diagram of a second embodiment of a PON network-based wireless signal forwarding apparatus according to the present invention;

fig. 6 is a schematic diagram of a second embodiment of a PON network-based wireless signal forwarding apparatus according to the present invention.

Detailed Description

The following is a detailed description of embodiments of the invention, but the invention can be practiced in many different ways, as defined and covered by the claims.

The invention provides a wireless signal forward transmission method based on a PON (Passive Optical Network) Network, and aims to provide a wireless signal forward transmission method based on the PON Network so as to achieve a method for achieving high-efficiency, low-cost and high-quality coverage of wireless signals (as shown in figures 4 to 6). Wherein the content of the first and second substances,

WDM: wavelet Division Multiplexing

OLT Optical line terminal;

ONU Unit, optical Network Unit;

passive Optical Network (Passive Optical Network);

ODN Optical Distribution Network

BBU Building Baseband Unit (base band processing Unit)

HUB-multiport repeater

CPRI Common Public Radio Interface

RU Radio Unit

Fig. 4 is a schematic diagram of a first embodiment of the present invention, as shown in fig. 4: the invention aims to provide a low-cost wireless signal forwarding covering method which can be configured with ONU units one to one under the point-to-multipoint networking application scene based on the existing PON network, and can configure the RU units of 3-4 times of the number of the ONU units under a PON port under certain complex scenes. As shown in fig. 4. According to the configuration that the first-level light splitting and the second-level light splitting are both 1. If more RU units are needed, such as FTTR networking application, 2 to 3 RU units can be cascaded under each RU unit, which is equivalent to that the number of ONU units corresponding to each PON port can reach 3 to 4 times, and the 4G/5G wireless signal forwarding scheme can adopt a three-level architecture and consists of three active network elements, namely a BBU, a HUB and an RU unit. The BBU device is co-located with the OLT device, the HUB is co-located with the secondary splitter (as shown in fig. 4), and the RU unit is co-located with the ONU unit.

In the invention, under the condition of using a pair of laser wavelengths lambda 7 and lambda 8, the number of HUBs directly connected with the BBU is recommended to be about 4-8, if 8 HUBs are provided, the HUBs can be exactly in one-to-one correspondence with the secondary optical splitters shown in the figure 4, but the maximum number of directly connected HUB units of the BBU also depends on the forwarding rate and the processed signal bandwidth. A time division CPRI forward transmission technology is adopted between the BBU unit and the HUB unit, specifically, a broadcast mode is adopted for a downlink, a time division mode is adopted for an uplink, the time division uplink transmission of each HUB unit needs to consider the transmission rate of the current PON, GPON can reach 2.5Gbps, XGPON can reach 10Gbps, and the transmission rate from the BBU unit to the HUB unit and then to the RU unit is more suitable in the range of 2.5Gbps to 10Gbps from the maturity and the cost of an industrial chain. Based on the forwarding rate and the processed signal bandwidth, the maximum number of uplink timeslots that can be allocated, that is, the maximum value of the direct-connected HUB unit corresponding to the BBU unit, can be determined.

Example 1, if NR30MHz/LTE20MHz is supported in the N1/B1 frequency band, 6.144Gbps is selected as the forward transmission rate from the BBU unit to the HUB unit; considering the mode of saving bandwidth most, the signals of NR30MHz and LTE20MHz are combined into signals of 50MHz bandwidth, the transmission rate required by the signals of 768mbps and the forwarding rate of 6.144gbps can just transmit 8 signals of 50MHz bandwidth, considering the transmission bandwidth required by management and control information and the protection interval during uplink time division transmission, one transmission bandwidth of 768Mbps can be reserved, only 7 transmission bandwidths of 768Mbps are taken to transmit 7 independent signals of 50MHz bandwidth, the uplink can be divided into 7 independent time slots, and the number of HUB units that can be directly connected with BBU unit is 7 at most.

Example 2, in the N41/B41 frequency band, NR 80MHz/LTE20MHz is supported, and 9.8304Gbps is selected as the forward transfer rate from the BBU unit to the HUB unit; considering the mode of saving bandwidth most, the forward transmission rate of 100MHz signal needed is 1.536Gbps,9.8304Gbps can transmit 6.4 wireless signals with 100MHz bandwidth, considering the transmission bandwidth needed by management and control information and the protection interval in uplink time division transmission, a certain transmission bandwidth can be reserved, and only 6 transmission bandwidths with 1.536Gbps are used for transmitting 6 independent wireless signals with 100MHz bandwidth. The uplink can be divided into 6 independent time slots, so that the maximum number of directly-connected HUB units which can be directly connected with the BBU units is calculated to be 6.

Example 3, in the N1/B1 frequency band, NR30MHz/LTE20MHz is supported, 9.8304Gbps is selected as the forwarding rate from the BBU unit to the HUB unit, according to the algorithms of the above examples 1 and 2, the uplink chain can be divided into 12 independent timeslots, the maximum number of HUB units directly connected to the BBU unit is 12, and under the condition of 1. However, considering that the number of the secondary optical splitters is generally only 8, it is recommended that the number of directly connected HUB units with BBU units is not more than 8 at most, and in the case of 12 independent timeslots, 4 HUB units may be allocated with two timeslots, another 4 HUB units are allocated with one timeslot, and one HUB unit allocated with more timeslots may also be flexibly processed; the HUB unit is allocated with two time slots, and uplink can transmit two independent data streams and support 2R uplink, so that the bandwidth of uplink service is doubled or the uplink diversity receiving function is increased. Examples 1 and 2, some of the HUB uplinks may be allocated two or more timeslots by reducing the number of HUB directly connected to BBU.

As shown in fig. 5: in some scenarios, for example, in a case where it is inconvenient to supply power to the HUB, the 4G5G wireless signal forwarding method of the present invention may also only adopt a two-stage architecture, and consists of two active network elements, i.e., a BBU unit and an RU unit, as shown in fig. 5; the BBU unit and OLT equipment are co-located, and the RU unit and ONU unit are co-located, can save the HUB unit of second grade beam split position department, can save the power supply of HUB unit. The RU unit and the ONU unit perform light splitting using wavelength division. In the case that the optical attenuation between the OLT device and the ONU unit is sufficient, the fronthaul wavelength between the BBU unit and the RU unit may also be increased, and the number of supported RU units may be doubled by increasing one upstream fronthaul wavelength, as shown in fig. 6; further, considering that the RU units and the ONU units can be configured one-to-one, the uplink bandwidth is halved or the number of subcarriers used in uplink is halved, and the number of RU units supported in fig. 6 can also be doubled.

As shown in fig. 6: two-stage architecture wireless signal coverage based on the PON network-two upstream wavelengths.

Example 4, in the case of a two-stage architecture, consisting of two active network elements, BBU, RU unit, as shown in fig. 5 and 6. In the N1/B1 frequency band, NR30MHz/LTE20MHz is supported, 9.8304Gbps is selected as the forwarding rate from the BBU unit to the RU unit, based on the foregoing algorithm, the uplink may be divided into 12 independent time slots, and the maximum number of RU units directly connected to the BBU unit is 12, as shown in fig. 5. If an uplink wavelength is added, that is, one transmitting laser is added to the RU unit, one receiving laser with the same wavelength is added to the BBU unit, and the same time division transmission mode is used, the number of RU units can be increased by 12, as shown in fig. 6, so that the maximum number of RU units directly connected to the BBU unit can be supported by 24. Considering that the RU units and the ONU units can be configured in one-to-one manner, the uplink bandwidth is halved or the number of subcarriers used in uplink is halved, the number of RU units supported in the case shown in fig. 6 may also be doubled, and the maximum number of RU units directly connected to the BBU may be supported by 48, which basically satisfies the one-to-one configuration of RU units and ONU units in the existing actual broadband networking.

Thus, define: forwarding bandwidth: BWTH, RU upstream bandwidth: BWRU, direct number: NTh, the following formula:

when BWTH is more than or equal to 0, BWRU-INT (BWTH is less than or equal to BWRU) <1%, NTh = INT (BWTH is less than or equal to BWRU) -1;

when BWTH/BWRU-INT (BWTH/BWRU) is more than or equal to 1%, NTh = INT (BWTH/BWRU).

The RU can support applications such as N1 frequency band 4T2R, 4T1R, 2T2R, 2T1R and the like, and can also support applications such as N1 frequency band 4T4R, or applications such as N1 frequency band 2T2R plus N78 frequency band 2T2R and the like; in the application of 4G/5G, the BBU can support 4G of a plurality of cells and 5G of the plurality of cells, each BBU supports 1 to 16 optical interfaces, and can support binding of a plurality of PON ports and also can introduce other 4G and 5G information sources to the BBU for centralized distribution processing. For example 2 above, a BBU port bound to one PON port may support 6 independent uplink timeslots, and if each 4G cell and each 5G cell support 2T2R, then at most 4G 2t2r for 3 cells and 5G 2t2r for 3 cells may be supported here. If each RU unit supports 2R (two antenna diversity or two independent upstream), then there can be up to 96 RU units supporting 2T 2R; if each RU unit supports only 1R, then a maximum of 192 2T1R RU units can be supported here. Such RU unit support capability may be 2 times (2T 2R) or 4 times (2T 1R) the number of actual ONU units under the corresponding PON, and then these cells may be rebundled to another PON port, and may be rebundled to one PON port (2T 2R application) or 3 PON ports (2T 1R application). For a villa coverage scenario or some enterprise coverage scenarios or other FTTR scenarios, it is also fully applicable that multiple RU units may be required to extend coverage under one ONU unit. The two 2T2R 5G cells may be combined into one 4T4R cell, or may support a 4T4R RU unit for higher traffic demand applications.

The 4G/5G BBU unit of the invention can support a plurality of time division CPRI interfaces, can bind a plurality of PON ports, and can realize the quick and flexible coverage as required of fewer users under each PON port based on the two-stage networking architecture of BBU-RU. With the increase of wireless users under the PON port, the HUB can be added to cover more users under the PON port. The combined application of the two-stage networking architecture of the BBU-RU and the three-stage networking architecture of the BBU-HUB-RU unit is also suitable for the comprehensive coverage of residential districts/apartments and office buildings.

The invention strictly controls the optical attenuation of the link introduced between the original OLT and the ONU unit. As shown in fig. 4, the light attenuation of the newly added link is introduced by the light of the WDM module and the RU unit of the two channels on the BBU side and the HUB side, with a typical loss of 2dB and a maximum loss of less than 2.5dB; one side of the HUB unit can also use light splitting, and the total introduced light attenuation can be controlled within 3 dB. As shown in fig. 5, the optical attenuation of the newly added link is introduced by two channels WDM at the BBU side and the RU unit side, the typical loss is 1.2dB, and the maximum loss is less than 2dB; as shown in fig. 6, the optical attenuation of the newly added link is introduced by the three-channel WDM at the BBU side and the RU unit side, the typical loss is 1.8dB, and the maximum loss is less than 2.5dB.

The BBU-HUB uses 1350/1530 under the condition of a three-level architecture, and an optical module needs to support a burst mode; the HUB-RU unit can use 1330/1550 or 1370/1550. The BBU-RU uses 1350/1530 in the case of the two-stage architecture, and the optical module needs to support burst mode.

For simplicity of description, the above example 2 application is taken as an example, as shown in fig. 4.

The method mainly comprises the following steps: the BBU unit returns back through the IPRAN resource of the machine room where the OLT equipment is located, and connection with a core network is established; service data is processed by a BBU unit baseband and is transmitted to a second-level light splitting box through a two-level light splitting network after an optical signal passing through a fronthaul interface of the BBU baseband and an optical signal passing through a PON port of OLT equipment are subjected to wavelength division multiplexing; the surplus optical fiber after the secondary light splitting is directly connected to the uplink port of the HUB unit, the HUB unit distributes and processes the baseband signals from the BBU unit to a plurality of extension optical ports of the HUB unit, the extension optical ports of the HUB unit and PON signals after the secondary light splitting are combined with WDM wavelength division as required, then the signals are transmitted to a user residence through a single optical fiber, the optical splitter is used for dividing the signals into two paths of optical signals, the RU unit and the ONU unit are respectively given, and the RU unit changes the baseband signals into wireless signals so as to complete the coverage of the wireless signals.

The invention has the following advantages:

2. The RU unit of the invention is installed and used with the existing broadband terminal to enter the home through the rubber-covered wire in the prior art, and the cables do not need to be laid again, thereby reducing the construction difficulty.

4. The invention has high quality of wireless signals and small interference.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered as the technical solutions and the inventive concepts of the present invention within the technical scope of the present invention.

Claims

1. A wireless signal forwarding method based on a PON (Passive optical network) is characterized by comprising the following steps: comprises a BBU unit and an RU unit; the BBU equipment and the OLT equipment are co-located, and the RU unit and the ONU unit are co-located; the BBU unit returns back through an IPRAN resource of a machine room where OLT equipment is located, and connection with a core network is established; the RU unit and the ONU unit are divided into two optical signals by using WDM, and the two optical signals are respectively sent to the RU unit and the ONU unit, the RU unit changes the baseband signal into a wireless signal so as to complete the coverage of the wireless signal,

further comprising: a HUB unit having an upstream interface C and an extended optical port; service data is processed by a BBU unit baseband and is transmitted to a second-level light splitting box through a two-level light splitting network after an optical signal passing through a fronthaul interface of the BBU baseband and an optical signal passing through a PON port of OLT equipment are subjected to wavelength division multiplexing; the surplus optical fiber after the secondary light splitting is directly connected to an uplink port C of the HUB, and the HUB unit distributes and processes baseband signals from the BBU and transmits the baseband signals to a plurality of extended optical ports of the HUB unit; the signal of the expansion optical port and the optical signal of the PON port after the second-stage light splitting are combined with the WDM wavelength according to requirements, then the signals are transmitted to a user through a single optical fiber, the signals are divided into two paths of optical signals through the optical splitter, the two paths of optical signals are respectively sent to the RU unit and the ONU unit, and the RU unit changes the baseband signals into wireless signals so as to complete the coverage of the wireless signals.

2. The PON network-based wireless signal forwarding method according to claim 1, wherein point-to-multipoint transmission is supported between the BBU unit and the HUB unit, the BBU unit uses laser wavelength λ 7 λ 8 for forwarding transmission, and time division CPRI is used between the BBU unit and the HUB unit for forwarding, wherein the downlink uses a broadcast mode, the uplink uses a time division mode, and each HUB uses time division uplink transmission.

3. The PON network-based wireless signal forwarding method of claim 2, wherein the downlink wavelength comprises λ 1 λ 5 λ 7 and the uplink wavelength comprises λ 2 λ 6 λ 8, wherein λ 1 λ 2 and λ 5 λ 6 are wavelengths used by OLT devices of GPON and XGPON, respectively, and have been combined into one fiber connected to one port of WDM; the wavelength lambda 7 lambda 8 is used by BBU of wireless signals, and each is connected to a wave selection channel of WDM by using one fiber.

4. The PON network-based wireless signal forwarding method of claim 1, wherein the BBU unit determines the number of the BBU units directly connected to the HUBs according to the maximum transmission bandwidth supported by the fronthaul optical interface and the uplink transmission bandwidth requirement of the RU unit.

5. A PON network-based wireless signal forwarding method as claimed in claim 4, wherein the formula for calculating the number NTh of HUBs is as follows: NTh = INT (BWTH/BWRU) -1, when 0 ≦ BWTH/BWRU-INT (BWTH/BWRU) <1%; NTh = INT (BWTH/BWRU), when BWTH/BWRU-INT (BWTH/BWRU) is more than or equal to 1%; wherein, RU uplink transmission bandwidth: BWRU; INT is an integer function; BWTH: and forwarding the bandwidth.

6. A wireless signal forwarding device based on a PON (passive optical network) is characterized in that: the system comprises a BBU and an RU unit, wherein the BBU unit and an OLT device are co-located, and the RU unit and an ONU unit are co-located; the BBU unit returns back through an IPRAN resource of a machine room where OLT equipment is located, and connection with a core network is established; the RU unit and the ONU unit are divided into two paths of optical signals by using an optical splitter and a WDM optical splitting unit, the two paths of optical signals are respectively sent to the RU unit and the ONU unit, the HUB unit also comprises a HUB unit, the HUB unit comprises a time-sharing CPRI interface connection which uses redundant optical fibers after secondary light splitting as an uplink port C and a BBU unit, and a plurality of extended optical ports, wherein the BBU equipment and the OLT equipment are co-located, and the HUB unit and the secondary optical splitter are co-located; and the BBU and the HUB are connected by adopting a time division CPRI forward transmission connection mode.

7. A PON network-based wireless signal forwarding device as claimed in claim 6, wherein the uplink port C of the HUB unit is a CPRI interface, and the extended optical port of the HUB unit is a point-to-point CPRI interface.

8. A PON network-based wireless signal forwarding apparatus according to claim 6, wherein: the BBU unit is integrated in the OLT equipment; the optical splitter and the WDM optical splitting unit can also be independently one component and are not arranged in the RU unit or the ONU unit equipment.