WO2019127069A1 - 一种下行信号发送方法以及基站 - Google Patents

一种下行信号发送方法以及基站 Download PDF

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Publication number
WO2019127069A1
WO2019127069A1 PCT/CN2017/118820 CN2017118820W WO2019127069A1 WO 2019127069 A1 WO2019127069 A1 WO 2019127069A1 CN 2017118820 W CN2017118820 W CN 2017118820W WO 2019127069 A1 WO2019127069 A1 WO 2019127069A1
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base station
subcarrier
communication system
modulation symbol
code
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PCT/CN2017/118820
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English (en)
French (fr)
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王新征
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华为技术有限公司
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Priority to PCT/CN2017/118820 priority Critical patent/WO2019127069A1/zh
Publication of WO2019127069A1 publication Critical patent/WO2019127069A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/02—Traffic management, e.g. flow control or congestion control
    • H04W28/04—Error control

Definitions

  • the present application relates to the field of communications, and in particular, to a downlink signal sending method and a base station.
  • the above problem can be solved by spectrum sharing, that is, two or more communication systems are served by the same spectrum.
  • the UMTS system and the LTE system or the NR system if the traffic of the UMTS system is low for a certain period of time and the traffic of the LTE system or the NR system is high, the UMTS system deactivates one or several carriers, and the UMTS deactivated carrier. It is reserved for use in LTE systems or NR systems. If the traffic of the UMTS system is high for a certain period of time and the traffic of the LTE system or the NR system is low, then LTE deactivates one or several carriers, and the LTE system or the NR system deactivated carrier is reserved for the UMTS system. .
  • the UMTS system Since the UMTS system must give the spectrum to the LTE system or the NR system in units of 5 MHz, if the UMTS system has only one 5 MHz carrier left, since the UMTS system still needs to be used by the user, it cannot continue to give up the 5 MHz, if it is given out At 5MHz, the UMTS system will have no resources available.
  • the embodiment of the present application provides a downlink signal sending method and a base station, configured to determine, according to the symbol of the subcarrier, that when the downlink signal is sent, the terminal that uses the spreading code or the scrambling code does not cause interference.
  • the first aspect of the embodiments of the present application provides a downlink signal sending method, including:
  • the first base station acquires code channel information of the second base station, where the first base station is a base station of a first communication system using orthogonal frequency division multiplexing (OFDM), and the second base station is a second using a spreading code or a scrambling code.
  • OFDM orthogonal frequency division multiplexing
  • a base station of a communication system the track information including an orthogonal variable spreading factor OVSF code used by the second base station and a scrambling code used by the second base station.
  • the first base station can determine the first modulation symbol of the first scheduling subcarrier, determine, according to the code channel information and the first modulation symbol, a second modulation symbol of the controlled subcarrier, the controlled subcarrier and the first
  • the scheduling subcarriers are different subcarriers, so that when the first base station sends the downlink signal by using the first scheduling subcarrier and the controlled subcarrier, the first scheduling subcarrier and the controlled subcarrier are jointly carried.
  • the downlink signal is orthogonal to the OVSF code, because the information in the downlink signal carried by the first scheduling subcarrier is transmitted to the terminal using the first communication system, and the interference signal is used to the terminal using the second communication system.
  • the downlink signal jointly carried by the first scheduling subcarrier and the controlled subcarrier is orthogonal to the OVSF code, so when the terminal using the second communication system receives the downlink signal and despreads the descrambling, the second is used.
  • the terminal of the communication system will not receive the information carried by the downlink signal, so that no interference is caused, so that different base stations and different terminals of the first communication system and the second communication system are used. You may share the same bandwidth resources without causing interference to a terminal of a second communications standard.
  • the method further includes: ensuring that the power of the first downlink signal is less than or equal to Preset power.
  • the preset power is set, so that when the calculated target carrier is transmitted, the power is less than the preset power, so that when the first base station sends the first downlink signal by using the target carrier, and the second communication system is used,
  • the terminal receives the first downlink signal, after despreading and descrambling the first downlink signal, little or no information is obtained, so that the interference is very small, so the first communication system and the second are used.
  • Different base stations and different terminals of the communication system can share the same bandwidth resource, thereby achieving communication without interference or interference.
  • the first base station determines the controlled subcarrier according to the code channel information and the first modulation symbol. Before the second modulation symbol, the first base station may further oversample the useful symbol of the OFDM according to the baseband sampling frequency of the second communication system, so that the baseband sampling frequency of the first communication system and the baseband of the second communication system The sampling frequency is equal.
  • the first base station and the second base station may be the same base station, and the first base station is configured with at least four antennas, wherein the four antennas are used to transmit the signal of the first communication system. At least 2 antennas are used to transmit signals of the second communication system.
  • the first base station acquires a third modulation symbol of a second scheduling subcarrier in the target carrier by using a third base station of the first communication system; the first base station according to the code channel information and Determining, by the first modulation symbol, the second modulation symbol of the controlled subcarrier, the first base station determining the second modulation symbol according to the third modulation symbol, the first modulation symbol, and the code channel information, so that the third
  • the second downlink signal that is jointly carried by the scheduling subcarrier and the controlled subcarrier is orthogonal to the OVSF code, and the controlled subcarrier and the second scheduling subcarrier are different subcarriers, so that multiple first communication systems are used.
  • the base station and the base station of a second communication system share the same spectrum resource.
  • the communication system using orthogonal frequency division multiplexing includes a long term evolution technology LTE system and a new wireless NR system.
  • the communication system using a spreading code or a scrambling code includes a universal mobile communication system UMTS system and a code division multiple access CDMA2000 system.
  • the first base station uses a root raised cosine filter.
  • a second aspect of the embodiments of the present application provides a base station, including:
  • An acquiring module configured to acquire code channel information of the second base station, where the code channel information includes an orthogonal variable spreading factor OVSF code used by the second base station, and a scrambling code used by the second base station, where the first base station is a base station of a first communication system using orthogonal frequency division multiplexing (OFDM), the second base station is a base station of a second communication system using a spreading code or a scrambling code; and a determining module, configured to determine a first of the first scheduling subcarriers a modulation module, configured to calculate, according to the code channel information and the first modulation symbol, a second modulation symbol of the controlled subcarrier, so that the downlink signal that is jointly carried by the first scheduling subcarrier and the controlled subcarrier
  • the control subcarrier is different from the first scheduling subcarrier
  • the sending module is configured to send the downlink signal by using the first scheduling subcarrier and the controlled subcarrier.
  • the calculation module is further configured to ensure that the power of the first downlink signal is less than or equal to a preset power.
  • the base station further includes: a sampling module, configured to perform a baseband sampling frequency pair according to the second communication system.
  • the useful symbols of OFDM are oversampled such that the baseband sampling frequency of the first communication system is equal to the baseband sampling frequency of the second communication system.
  • the acquiring module is further configured to acquire a third modulation symbol of a second scheduling subcarrier in the target carrier by using a third base station of the first communication system; Calculating the second modulation symbol according to the third modulation symbol, the first modulation symbol, and the code channel information, so that the second downlink signal and the OVSF code jointly carried by the third scheduling subcarrier and the controlled subcarrier are Orthogonal, the controlled subcarrier is different from the second scheduled subcarrier.
  • a third aspect of the embodiments of the present application provides a base station, including: a transceiver, a processor, and a memory; the transceiver is configured to acquire code channel information of the second base station, where the code channel information includes the first An orthogonal variable spreading factor OVSF code used by the second base station and a scrambling code used by the second base station, the first base station being a base station of a first communication system using orthogonal frequency division multiplexing (OFDM), the second base station is a base station of a second communication system using a spreading code or a scrambling code; the processor, configured to determine a first modulation symbol of the first scheduling subcarrier, and determine a controlled subcarrier according to the code channel information and the first modulation symbol The second modulation symbol is such that the downlink signal jointly carried by the first scheduling subcarrier and the controlled subcarrier is orthogonal to the OVSF code, and the controlled subcarrier and the first scheduling subcarrier are different subcarriers;
  • the transceiver
  • Yet another aspect of the present application provides a computer readable storage medium having instructions stored therein that, when executed on a computer, cause the computer to perform the methods described in the above aspects.
  • the first base station is a base station of a first communication system that uses orthogonal frequency division multiplexing (OFDM), and the second base station is a base station of a second communication system that uses a spreading code or a scrambling code.
  • OFDM orthogonal frequency division multiplexing
  • the first base station may acquire code channel information of the second base station and determine a first modulation symbol of the first scheduling subcarrier, where the code channel information includes an orthogonal variable spreading factor OVSF code used by the second base station, and the second a scrambling code used by the base station, after which the second modulation symbol of the controlled subcarrier may be determined according to the code channel information and the first modulation symbol, so that when the first base station uses the first scheduling subcarrier and the controlled When the subcarrier transmits the downlink signal, the information in the downlink signal carried by the first scheduling subcarrier is sent to the terminal using the first communication system, and is an interference signal to the terminal using the second communication system.
  • the code channel information includes an orthogonal variable spreading factor OVSF code used by the second base station
  • the second a scrambling code used by the base station after which the second modulation symbol of the controlled subcarrier may be determined according to the code channel information and the first modulation symbol, so that when the first base station uses the first scheduling subcarrier and the controlled
  • the downlink signal jointly carried by the first scheduling subcarrier and the controlled subcarrier is orthogonal to the OVSF code, so when the terminal using the second communication system receives the downlink signal and despreads the descrambling, the use
  • the terminal of the second communication system will not receive the information carried by the downlink signal, so that no interference is caused, so that different base stations and different terminals using the first communication system and the second communication system can share the same bandwidth resource, and It does not cause interference to terminals using the second communication system.
  • FIG. 1 is a schematic diagram of an embodiment of a downlink signal sending method in the present application
  • FIG. 2 is a schematic diagram of an embodiment of a downlink signal sending method according to the present application.
  • FIG. 3 is a schematic diagram of a value-added manner of a UMTS spreading code
  • 4 is a schematic diagram showing temporal correspondence between OFDM useful symbols and UMTS spreading codes
  • 5 is a schematic diagram of an equivalent OVSF code used with OFDM symbols and UMTS;
  • FIG. 6 is a schematic diagram of power spectral density of LTE and 5 MHz UMTS signals for a 3 MHz system bandwidth
  • FIG. 7 is a schematic diagram of a receive filter of a 5 MHz LTE system and a UMTS UE;
  • FIG. 8 is a schematic diagram of a plurality of non-second communication systems and a second communication system sharing spectrum
  • FIG. 9 is a schematic diagram of an embodiment of a base station 900.
  • FIG. 10 is a schematic diagram of another embodiment of a base station 900.
  • FIG. 1 is a system structure in an embodiment of the present application, including a base station and a plurality of terminals, where a plurality of terminals include a first communication system and a second communication system, and in the embodiment of the present application, A communication system is described by taking UMTS as an example, and a second communication system is described by taking LTE as an example.
  • the base station in the embodiment of the present application which may also be referred to as a base station device, is a device deployed in a radio access network to provide a wireless communication function.
  • the name of a base station may be different in different wireless access systems.
  • a base station is called a Node B
  • a base station in an LTE network is called a base station.
  • a base station in an LTE network is called a base station.
  • a base station in a new radio (NR) network is called a transmission reception point (TRP) or a generation node B (gNB).
  • TRP transmission reception point
  • gNB generation node B
  • other base stations may be used in other networks where multiple technologies are converged, or in other various evolved networks. The invention is not limited to this.
  • a terminal also referred to as a user device, is a device that provides voice and/or data connectivity to a user, for example, a handheld device with wireless connectivity, an in-vehicle device, and the like.
  • Common terminals include, for example, mobile phones, tablets, notebook computers, PDAs, mobile internet devices (MIDs), wearable devices such as smart watches, smart bracelets, pedometers, and the like.
  • MIDs mobile internet devices
  • wearable devices such as smart watches, smart bracelets, pedometers, and the like.
  • the density of IoT terminals may be 10 times higher than the density of existing mobile phones, that is, 10 connected terminals per capita, cars, bicycles, air conditioners, lamps, curtains, door locks, electric meters, watches. , clothing, hats, audio, luggage can be connected to the Internet, express delivery will also be real-time viewing, industrial robots through the network configuration, etc., the Internet of Things will become the biggest highlight of changing people's lives.
  • the baseband chip of the 5G terminal has more computing power, and the baseband upgrade is also the improvement of the mobile phone core processor.
  • the baseband chip includes the CPU processor, channel encoder, digital signal processor, modem and interface module, and advanced coding.
  • Modulation puts forward requirements for channel encoders; new multi-access and new multi-carriers put forward requirements for modems; large-scale MIMO, full-duplex, high-band communication, and ultra-dense networking have raised the amount of data and proposed for the entire chip.
  • Claim. The antenna of the 5G terminal is more diverse. In addition to the current dual antenna, multi-antenna technology will appear. At the same time, the high-band small-sized antenna will be integrated into the mobile phone.
  • the base station can simultaneously have multiple communication system functions, that is, the capability of simultaneously serving multiple terminals using multiple communication systems. For example, the base station can notify the UMTS and LTE functions, and can simultaneously serve UMTS and LTE. The capabilities of the terminal.
  • the UMTS system deactivates one or several carriers, and the UMTS deactivated carrier is left to the LTE.
  • the system uses; if the traffic of the UMTS system is high for a certain period of time and the traffic of the LTE system is low, then LTE deactivates one or several carriers, and the LTE deactivated carrier is reserved for the UMTS system. Since the UMTS system must give the spectrum to the LTE system or the NR system in units of 5 MHz, if the UMTS system has only one 5 MHz carrier left, the 5 MHz cannot be continued.
  • the first base station is a base station that uses orthogonal frequency division multiplexing (such as LTE or NR), and the second base station is a second communication system that uses a spreading code or a scrambling code (
  • the first base station transmits the downlink signal by using the target carrier
  • the information in the downlink signal carried by the first scheduling subcarrier in the target carrier is sent to the terminal using the first communication system, and is used.
  • the terminal of the second communication system is an interference signal
  • the target carrier further includes a controlled subcarrier different from the first scheduling subcarrier, and the second modulation symbol of the controlled subcarrier is according to the first scheduling subcarrier.
  • the downlink signal of the bearer is orthogonal to the OVSF code. Therefore, when the terminal using the second communication system receives the downlink signal and despreads the descrambling, the terminal using the second communication system will not obtain the downlink signal. Hosted Information so as not to cause interference, so using the first communication standard and the second communication standard different terminals and different base stations can share the same bandwidth resources without causing interference to a terminal of a second communications standard.
  • an embodiment of a downlink signal sending method in this application includes:
  • the first base station acquires code channel information of the second base station.
  • the first base station may acquire, in advance, code channel information of the second base station, where the code channel information includes an orthogonal variable spreading factor OVSF code used by the second base station, and a used interference of the second base station. code.
  • the first base station is a base station of a first communication system using orthogonal frequency division multiplexing (OFDM)
  • the second base station is a base station of a second communication system using a spreading code or a scrambling code.
  • the first communication system is a communication system using Orthogonal Frequency Division Multiplexing (OFDM), and the first communication system is one of Multi-Carrier Modulation (MCM).
  • OFDM Orthogonal Frequency Division Multiplexing
  • MCM Multi-Carrier Modulation
  • a data stream is decomposed into a number of sub-streams such that the sub-streams have a much lower transmission bit rate, and the data is used to separately modulate several sub-carriers.
  • the channel is divided into a plurality of orthogonal subchannels, and the high speed data signal is converted into parallel low speed sub data streams, modulated to be transmitted on each subchannel, and the orthogonal signals can pass.
  • the receiving end uses correlation techniques to separate, so that mutual interference between subchannels can be reduced, and the signal bandwidth on each subchannel is smaller than the relevant bandwidth of the channel, so that each subchannel can be regarded as flatness fading, thereby eliminating symbols.
  • Inter-channel interference and since the bandwidth of each sub-channel is only a small fraction of the original channel bandwidth, channel equalization becomes relatively easy.
  • the first communication system may include a communication system of Long Term Evolution (LTE) and a communication system of a new wireless NR.
  • LTE Long Term Evolution
  • 3GPP 3rd Generation Partnership Project
  • MIMO Multi-Input & Multi-Output
  • the LTE system supports multiple bandwidth allocations: 1.4MHz, 3MHz, 5MHz, 10MHz, 15MHz and 20MHz, and supports the global mainstream 2G/3G frequency band and some new frequency bands, so the spectrum allocation is more flexible, and the system capacity and coverage are also significant. Upgrade.
  • the second base station is a base station of a second communication system using a spreading code or a scrambling code, such as a Universal Mobile Telecommunications System (UMTS) system and code division multiple access (Code).
  • a spreading code or a scrambling code such as a Universal Mobile Telecommunications System (UMTS) system and code division multiple access (Code).
  • UMTS Universal Mobile Telecommunications System
  • Code division multiple access 2000 CDMA2000
  • CDMA2000 is a wireless spread spectrum communication technology that appears in the process of digital mobile communication, with high spectrum utilization, good voice quality, strong confidentiality, low dropped call rate, and small electromagnetic radiation. , large capacity, wide coverage and so on.
  • the spreading code is also referred to as a channelization code, and is used to distinguish different transmission connections from the same cell. From the downlink signal, the spreading code is used to distinguish different link connections of one cell.
  • the first base station and the second base station may be the same base station or different base stations. If the same base station is used, different antennas may be used to separately transmit signals of the first communication system and the second communication system, which are not limited herein.
  • first base station and the second base station are the same base station, when the first communication system and the second communication system that require the co-site transmission have different numbers of transmitting antennas respectively, different communication systems use different numbers of transmissions.
  • the antenna is transmitted, and the signal of the system with a small number of transmitting antennas is copied to several antennas used in a system that occupies a large number of transmitting antennas.
  • the first communication system is transmitted at four antennas, including two antennas a and b of the second communication system, and then the first base station (or the second base station) respectively transmits a/sqrt(2), a/sqrt( 2), b/sqrt(2), b/sqrt(2), can also send a, b/sqrt(3), b/sqrt(3), b/sqrt(3), and can also send a/sqrt. (3), a/sqrt(3), a/sqrt(3), b, which are not limited here. (sqrt is Square Root Calculations, which is the square root calculation)
  • the downlink signal sent by the second base station is a superposition of signals of different physical channels, and the physical channel application cell other than the SCH (including the P-SCH and the S-SCH)
  • a specific scrambling code that is, different physical channels of one cell use the same scrambling code, and different OVSF codes (spreading codes), which are usually called different code channels.
  • the spreading code used in the UMTS system takes the value according to the method shown in FIG. 3 (the schematic diagram of the value of the spreading code of the UMTS), and the value of each element in the sequence of the spreading code is 1 or -1.
  • the length of the scrambling code used in the downlink is 38,400 chips, corresponding to a radio frame length of 10 ms, and each element of the scrambling sequence is a complex number of modulo 1.
  • the first base station determines a first modulation symbol of the first scheduling subcarrier.
  • the first scheduling subcarrier and the first modulation symbol in the target carrier may be determined according to the related protocol, where the first scheduling The subcarrier is configured to carry a subcarrier that transmits a downlink signal to a terminal that uses the first communication system, to determine that when the first base station sends the downlink signal by using the target carrier, the terminal of the first communication system can receive related information.
  • the first base station determines a second modulation symbol of the controlled subcarrier according to the code channel information and the first modulation symbol.
  • the controlled sub The carrier is different from the first scheduling subcarrier, so that the downlink signal jointly carried by the first scheduling subcarrier and the controlled subcarrier is orthogonal to the OVSF code.
  • the difference between the baseband sampling frequency of the LTE or NR and the baseband sampling frequency of the UMTS may result in a calculation method thereof. different.
  • the interface between the baseband unit (BBU) and the radio remote unit (RRU) in a base station is a common public radio interface (CPRI) interface.
  • the CPRI interface passes the baseband signal samples.
  • the sampling frequency of the CPRI interface of the UMTS downlink is 3.84 MHz.
  • the 4G LTE system is divided into Time Division Duplexing (TDD) and Frequency Division Duplexing (FDD).
  • the downlink signal different from UMTS is the superposition of signals of different code channels, and the downlink of LTE.
  • the signal is a superposition of subcarrier signals of different frequencies.
  • the duration of a useful OFDM symbol is This duration is equal to the duration of 256 chips in UMTS because
  • the sampling frequency of the LTE baseband signal is equal to the product of the number of FFT points and the subcarrier spacing. It is easy to know that one useful OFDM symbol of LTE is sampled into "FFT points" sample points.
  • sampling frequency in the actual system can be higher than the value in Table 1, that is, oversampling, and the LTE system can also deploy multiple carriers, wherein the bandwidth of each carrier is selected in Table 1 (according to the protocol, The bandwidth selection of the carriers will have different limits in different frequency bands, which are not arbitrarily selected from the table.
  • the "FFT points" in Table 1 is the value generally used in the product implementation, and other values may be used.
  • Table 1 Parameters related to LTE systems with different system bandwidths
  • the baseband sampling frequency of LTE or NR is equal to the baseband sampling frequency of UMTS.
  • the baseband signal sampling frequency of the LTE system with the system bandwidth of 3 MHz as shown in Table 1 is equal to the baseband sampling frequency of the UMTS 3.84. MHz.
  • Table 1 the baseband sampling frequency of the UMTS 3.84. MHz.
  • the starting moment of a useful OFDM symbol in an LTE system is not necessarily the same as the starting moment of a symbol in a UMTS system.
  • the useful OFDM symbol and a symbol in the UMTS system are as shown in FIG. 4. (Similar diagram of the correspondence between the OFDM useful symbols and the UMTS spreading code in time) The same scenario is shown.
  • the length of the label P-CPICH in FIG. 4 corresponds to the duration of one symbol of the P-CPICH, and the symbol is spread by the OVSF code whose SF is 256, and each symbol is expanded into 256 chips. This duration is exactly equal to the duration of the OFDM useful symbol.
  • the two strips labeled "SF128, eg, R99etc.” correspond to the duration of two symbols of the channel spread using the OVSF code with SF 128, each symbol being Expanded to 128 chips, the two symbols are exactly 256 chips, and the total duration is equal to the duration of one OFDM useful symbol.
  • the first base station selects N 1 subcarriers from the target carrier (5 MHz) as the first scheduling subcarrier, and their corresponding inverse fast Fourier transform IFFT index (counted from 1) is recorded as K 1 , the first The N 1 ⁇ 1 column vector formed by the first modulation symbol of the scheduling subcarrier is denoted as s, and then a part of the unused subcarriers other than the scheduling subcarrier in the target carrier in LTE is selected as the controlled sub Carrier.
  • the controlled subcarrier may be a subcarrier that is not currently scheduled, or may be a subcarrier on the guard band, which is not limited herein.
  • the set of their corresponding IFFT indexes (counted from 1) is denoted as K 2
  • the column vector of N 1 ⁇ 1 formed by the modulation symbols transmitted on these subcarriers is recorded as x.
  • G be a normalized discrete Fourier inverse IDFT matrix of L ⁇ L.
  • the system bandwidth is 3 MHz
  • the FFT point is 256, that is, L is 256
  • the G The element of the nth (1 ⁇ n ⁇ 256) column of m(1 ⁇ m ⁇ 256) is Where j is an imaginary unit.
  • the 256 ⁇ 1 column vector is u n
  • the 128 ⁇ 1 column vector composed of the OVSF code C ch, 128, k is v k .
  • the terminal in the UMTS system obtains (2M+2) symbols after the signal of the received LTE system is descrambled and despread (the SF of two symbols is 256, and the SF of the remaining 2M symbols is 128).
  • the first The power of the downlink signal is less than or equal to the preset power, and thus the preset power is set, so that when the calculated target carrier is transmitted, the power is less than the preset power, so that when the first base station uses the target carrier to send the first a downlink signal, and when the terminal using the second communication system receives the first downlink signal, after despreading and descrambling the first downlink signal, little or no information is obtained, so that the interference is very small. Therefore, different base stations and different terminals using the first communication system and the second communication system can share the same bandwidth resource, thereby implementing communication without interference or less interference.
  • the additional code channel power of the UMTS does not exceed the preset power P.
  • I is the identity matrix, and the larger ⁇ 0 is, The smaller the norm, the best ⁇ 0 can be found by binary search.
  • the interference power from LTE seen by the UTMS terminal descrambled and despread is as small as possible.
  • the terminal is an interference signal for the terminal using the second communication system, and since the terminal using the second communication system receives the downlink signal and despreads the descrambling, no information is obtained or obtained, so that The type of interference is very small, so different base stations and different terminals using the first communication system and the second communication system can share the same bandwidth resource, thereby achieving communication without interference or less interference.
  • the baseband sampling frequency of LTE or NR is less than the baseband sampling frequency of UMTS.
  • the LTE or NR when the baseband sampling frequency of the LTE or NR is less than the baseband sampling frequency of the UMTS, the LTE or NR may be oversampled so that the sampling frequency is equal to the sampling frequency of the UMTS, and then the above "one," Process.
  • an oversampling method is to perform a larger number of IFFTs, for example, a normal 128-point FFT and IFFT for a 1.4 MHz LTE system, but 256 points like a 3 MHz LTE system.
  • FFT and Fast Fourier Transform IFFT are not described here.
  • the baseband sampling frequency of LTE or NR is greater than the baseband sampling frequency of UMTS.
  • the baseband signal sampling frequency of the LTE is greater than the baseband sampling frequency of the UMTS, and the LTE or NR signal occupies a larger bandwidth than the UMTS.
  • the bandwidth of the RRC filter that is, the RRC filter of the terminal of the UMTS affects the LTE signal, can be calculated in the following manner:
  • the setting method here is the same as the setting method in “1.”, and will not be described here.
  • G' be the normalized discrete Fourier transform IDFT matrix of L' ⁇ L'(L' is the number of IFFT points used by the first base station, see Table 1), where L'>L), the first of G
  • the element of the nth (1 ⁇ n ⁇ L') row of m (1 ⁇ m ⁇ L') is Where j is an imaginary unit.
  • the sampling frequency is greater than 3.84 MHz.
  • the receive filter (which is an RRC filter) specifies the unit impulse response of the RRC filter used by the UMTS according to section 6.8.1 of the 3GPP protocol TS 25.104:
  • h(n) can be truncated to length 2F+1, and the downlink signal passes through the receiving filter of the terminal of the second communication system, that is, the signal sample is linearly convolved with h(n). Only the useful OFDM symbol g and h(n) linear convolution are considered here. After the linear convolution, the first F values are removed, and the L' values starting from the F+1 value form the L' ⁇ 1 vector. g', expressed as a matrix operation as:
  • the matrix H of L' ⁇ L' is composed of h(-F), h(-F+1), ..., h(F).
  • the terminal of the second communication system processes the received downlink signal in the manner of processing the received downlink signal, and downsamples g', and the downsampling factor is L'/256, that is, each L'/256 values are taken out.
  • the first value here assuming L'/256 is an integer, after downsampling, a 256 ⁇ 1 vector g" is obtained, where g" can be represented by a matrix operation as:
  • the setting method here is the same as the power optimization mode in “1.” and will not be described here.
  • This method can improve performance when the OVSF code used by UMTS is regularly arranged on the code tree (that is, the terminal of the UTMS is less interfered by LTE or NR), and does not significantly increase the complexity.
  • Selecting the controlled subcarriers makes the time domain signal of OFDM on the time periods B, C, and D shown in FIG. 5 and the OVSF code.
  • the following example is used to illustrate that the UMTS and the 5 MHz LTE share the downlink spectrum.
  • the baseband sampling rate of the 5 MHz LTE system is 7.68 MHz larger than the baseband sampling frequency of the UMTS 3.84 MHz, and the subcarrier of the LTE system and the terminal of the UMTS are received.
  • the filter is shown in Figure 6 (schematic diagram of the power spectral density of LTE and 5 MHz UMTS signals for a 3 MHz system bandwidth).
  • the "DC" in FIG. 6 represents a DC subcarrier, and the protocol stipulates that the subcarrier is not used.
  • the subcarrier of the UMTS marked in FIG. 6 is a subcarrier within the receiving band of the LTE protection band and falls into the terminal of the UMTS.
  • the scheduled subcarriers are in the vicinity of the DC, and the controlled subcarriers include a portion of the unscheduled subcarriers and the subcarriers on the guard band.
  • the scheduled subcarrier transmits data sent to the terminal of the LTE, and the controlled subcarrier takes a value according to the foregoing method.
  • the value of the controlled subcarrier is related to the value of the scheduled subcarrier and the code channel of the UMTS to be "avoided" and the scrambling code used by the UTMS.
  • the LTE waveform Due to the presence of the controlled subcarriers, the LTE waveform is changed, and as a result of the change, the UMTS terminal does not see (ideally only) the LTE signal when descrambling and despreading the code channel it needs.
  • the controlled subcarriers should not transmit data, and some specific value data is sent after the application is applied.
  • the LTE and UMTS signals are approximately orthogonal by the controlled subcarriers, and the UMTS terminal is in the When the UMTS signal on a certain path is descrambled, the LTE signal is the same as the UMTS signal delay (for example, also on the path), and the LTE signal does not interfere with the UMTS signal.
  • the information in the downlink signal of the first scheduling subcarrier is transmitted to the terminal using the first communication system, it is an interference signal to the terminal using the second communication system, and is received by the terminal using the second communication system.
  • the downlink signal is despread and descrambled, no or very little information is obtained, so that such interference is very small, so different base stations and different terminals using the first communication system and the second communication system can share the same Bandwidth resources to achieve communication without interference or interference.
  • the first base station sends the downlink signal by using the first scheduling subcarrier and the controlled subcarrier.
  • the first scheduling subcarrier and the controlled subcarrier may be used to send the downlink signal, so that the terminal and the using the first communication system are used.
  • the terminal of the second communication system can receive the downlink signal. Since the information in the downlink signal of the first scheduling subcarrier is transmitted to the terminal using the first communication system, it is an interference signal to the terminal using the second communication system, and is received by the terminal using the second communication system. After the downlink signal is despread and descrambled, no or very little information is obtained, so that such interference is very small, so different base stations and different terminals using the first communication system and the second communication system can share the same Bandwidth resources to achieve communication without interference or interference.
  • the first base station may use a root raised cosine filter as a transmit filter to share the transmit module with the second base station (referred to as UMTS).
  • UMTS root raised cosine filter
  • Figure 7 (a schematic diagram of a receive filter of a 5 MHz LTE system and a UMTS UE) compares the power spectral density of a 3 MHz system bandwidth LTE and a 5 MHz UMTS signal, and the LTE PSD has a falling spike at the 0 frequency because LTE does not transmit data on the DC subcarriers.
  • the square of the mode of the amplitude-frequency response of the receive filter and the transmit filter of the UMTS has the same shape as the PSD of the UMTS signal.
  • the UMTS receive filter has less impact on the LTE signal of the 3 MHz system bandwidth because the PSD of the LTE signal has dropped by about 30 dB at the frequency at which the filter's amplitude response begins to fall from the horizontal.
  • the LTE of the LTE with less bandwidth or the NR with less bandwidth and no transmission filter may also be added.
  • a transmit filter like UMTS that allows small bandwidth LTE (eg 3 MHz system bandwidth) or NR plus a transmit filter means that the LTE or NR baseband signal can be superimposed with the UMTS baseband signal and then transmitted through the same RRU. Going out, this can reduce costs.
  • the non-second communication system in FIG. 8 may refer to the same communication.
  • the system may also refer to different communication systems, which are not limited herein.
  • the frequency range occupied by the non-second communication system may be slightly larger than 5 MHz as needed, and the ellipsis on the right side of FIG. 8 indicates that more non-second communication systems may be placed side by side, each The non-second communication system has a controlled sub-carrier.
  • the base station determines the controlled sub-carrier, a plurality of communication systems are comprehensively considered, which is not limited herein.
  • a base station 900 includes:
  • the obtaining module 901 is configured to obtain code channel information of the second base station, where the code channel information includes an orthogonal variable spreading factor OVSF code used by the second base station, and a scrambling code used by the second base station, where the first base station A base station of a first communication system using Orthogonal Frequency Division Multiplexing (OFDM), which is a base station of a second communication system using a spreading code or a scrambling code.
  • OFDM Orthogonal Frequency Division Multiplexing
  • the determining module 902 is configured to determine a first modulation symbol of the first scheduling subcarrier.
  • the calculating module 903 is configured to calculate, according to the code channel information and the first modulation symbol, a second modulation symbol of the controlled subcarrier, so that the downlink signal jointly carried by the first scheduling subcarrier and the controlled subcarrier is
  • the OVSF code is orthogonal, and the controlled subcarrier is a different subcarrier from the first scheduling subcarrier.
  • the sending module 904 is configured to send the downlink signal by using the first scheduling subcarrier and the controlled subcarrier.
  • the information in the downlink signal carried by the first scheduling subcarrier is sent to the terminal using the first communication system, and is the interference signal for the terminal using the second communication system, and the first scheduling subcarrier and the received
  • the downlink signal jointly carried by the control subcarriers is orthogonal to the OVSF code. Therefore, when the terminal using the second communication system receives the downlink signal and despreads the descrambling, the terminal using the second communication system will not receive the downlink communication system.
  • the information carried by the downlink signal is such that no interference is caused, so that different base stations and different terminals using the first communication system and the second communication system can share the same bandwidth resource without causing a terminal using the second communication standard. Interference.
  • the calculating module 902 is further configured to ensure that the power of the first downlink signal is less than or equal to a preset power.
  • the base station 900 further includes:
  • the sampling module 905 is configured to oversample the useful symbol of the OFDM according to the baseband sampling frequency of the second communication system, so that the baseband sampling frequency of the first communication system is equal to the baseband sampling frequency of the second communication system.
  • the obtaining module 901 is further configured to acquire a third modulation symbol of a second scheduling subcarrier in the target carrier by using a third base station of the first communication system.
  • the calculating module 903 is further configured to calculate the second modulation symbol according to the third modulation symbol, the first modulation symbol, and the code channel information, so that the third scheduling subcarrier and the controlled subcarrier are jointly carried by
  • the second downlink signal is orthogonal to the OVSF code, and the controlled subcarrier and the second scheduling subcarrier are different subcarriers.
  • the embodiment of the present application is described above from the perspective of a modular functional entity. The following describes the embodiment of the present application from the perspective of hardware processing. Referring to FIG. 10, the embodiment of the present application provides a base station 1000:
  • the transceiver 1001 is configured to acquire code channel information of the second base station, where the code channel information includes an orthogonal variable spreading factor OVSF code used by the second base station, and a scrambling code used by the second base station, where the first
  • the base station is a base station of a first communication system using orthogonal frequency division multiplexing (OFDM)
  • the second base station is a base station of a second communication system using a spreading code or a scrambling code.
  • the processor 1002 is configured to determine a first modulation symbol of the first scheduling subcarrier, and determine a second modulation symbol of the controlled subcarrier according to the code channel information and the first modulation symbol, so that the first scheduling subcarrier and The downlink signal jointly carried by the controlled subcarrier is orthogonal to the OVSF code, and the controlled subcarrier is different from the first scheduling subcarrier.
  • the transceiver 1001 is further configured to send the downlink signal by using the first scheduling subcarrier and the controlled subcarrier.
  • the memory 1003 is configured to store a program, the code channel information, a first modulation symbol of the first scheduling subcarrier, and a second modulation symbol of the controlled subcarrier.
  • the information in the downlink signal carried by the first scheduling subcarrier is sent to the terminal using the first communication system, and is the interference signal for the terminal using the second communication system, and the first scheduling subcarrier and the received
  • the downlink signal jointly carried by the control subcarriers is orthogonal to the OVSF code. Therefore, when the terminal using the second communication system receives the downlink signal and despreads the descrambling, the terminal using the second communication system will not receive the downlink communication system.
  • the information carried by the downlink signal is such that no interference is caused, so that different base stations and different terminals using the first communication system and the second communication system can share the same bandwidth resource without causing a terminal using the second communication standard. Interference.
  • the computer program product includes one or more computer instructions.
  • the computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable device.
  • the computer instructions can be stored in a computer readable storage medium or transferred from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions can be from a website site, computer, server or data center Transfer to another website site, computer, server, or data center by wire (eg, coaxial cable, fiber optic, digital subscriber line (DSL), or wireless (eg, infrared, wireless, microwave, etc.).
  • wire eg, coaxial cable, fiber optic, digital subscriber line (DSL), or wireless (eg, infrared, wireless, microwave, etc.).
  • the computer readable storage medium can be any available media that can be stored by a computer or a data storage device such as a server, data center, or the like that includes one or more available media.
  • the usable medium may be a magnetic medium (eg, a floppy disk, a hard disk, a magnetic tape), an optical medium (eg, a DVD), or a semiconductor medium (such as a solid state disk (SSD)).
  • the disclosed system, apparatus, and method may be implemented in other manners.
  • the device embodiments described above are merely illustrative.
  • the division of the unit is only a logical function division.
  • there may be another division manner for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored or not executed.
  • the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.
  • the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.
  • each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.
  • the above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.
  • the integrated unit if implemented in the form of a software functional unit and sold or used as a standalone product, may be stored in a computer readable storage medium.
  • a computer readable storage medium A number of instructions are included to cause a computer device (which may be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present application.
  • the foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and the like. .

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Abstract

本申请实施例公开了一种下行信号发送方法以及基站，用于根据确定子载波的符号，使得发送下行信号时，对使用扩频码或扰码的终端不造成干扰。本申请实施例方法包括：第一基站获取第二基站的码道信息；所述第一基站确定第一调度子载波的第一调制符号；所述第一基站根据所述码道信息和所述第一调制符号确定受控子载波的第二调制符号，以使得所述第一调度子载波和所述受控子载波所共同承载的下行信号与所述OVSF码正交，所述受控子载波与所述第一调度子载波是不同的子载波；所述第一基站使用所述第一调度子载波和所述受控子载波发送所述下行信号。

Description

一种下行信号发送方法以及基站 技术领域
本申请涉及通信领域，尤其涉及一种下行信号发送方法以及基站。
背景技术
随着移动通信产业的发展，用户逐渐从旧的通信系统向新的通信系统迁移，如用户从2G或3G向4G或5G迁移。用户的迁移使得旧的通信系统的频谱越来越空闲，新的通信系统的频谱越来越紧张，但是旧的通信系统的用户数不会立刻降为0，有可能在较长时间内维持在一定水平上，因此运营商不能关闭旧的通信系统，并将其频谱用在新的通信系统上。
当下，可以通过频谱共享来解决上述问题，即同一段频谱服务两个或多个通信系统。例如UMTS系统和LTE系统或NR系统，如果某段时间UMTS系统的业务量低而LTE系统或NR系统的业务量高，那么UMTS系统就去激活某个或某几个载波，UMTS去激活的载波就留给LTE系统或NR系统使用。如果某段时间UMTS系统的业务量高而LTE系统或NR系统的业务量低，那么就LTE就去激活某个或某几个载波，LTE系统或NR系统去激活的载波就留给UMTS系统使用。
由于UMTS系统对LTE系统或NR系统让出频谱必须以5MHz为单位，如果UMTS系统只剩下一个5MHz的载波，由于UMTS系统还有用户需要使用，则无法继续让出该5MHz，如果让出了该5MHz，则UMTS系统将无资源可用。
发明内容
本申请实施例提供了一种下行信号发送方法以及基站，用于根据确定子载波的符号，使得发送下行信号时，对使用扩频码或扰码的终端不造成干扰。
有鉴于此，本申请实施例的第一方面提供一种下行信号发送方法，包括：
第一基站获取第二基站的码道信息，其中，该第一基站为使用正交频分复用OFDM的第一通信制式的基站，该第二基站为使用扩频码或扰码的第二通信制式的基站，该码道信息包括了该第二基站使用的正交可变扩频因子OVSF码和该第二基站所使用的扰码。则该第一基站可以确定第一调度子载波的第一调制符号之后，根据该码道信息和该第一调制符号确定受控子载波的第二调制符号，该受控子载波与该第一调度子载波是不同的子载波，以至于当该第一基站使用该第一调度子载波和该受控子载波发送该下行信号时，该第一调度子载波和该受控子载波所共同承载的下行信号与该OVSF码正交，由于第一调度子载波所承载的下行信号内的信息是发送给使用该第一通信制式的终端的，对于使用第二通信制式的终端来说是干扰信号，该第一调度子载波和该受控子载波所共同承载的下行信号与该OVSF码正交，因此当使用第二通信制式的终端接收到该下行信号并解扩解扰后，使用第二通信制式的终端将会得不到该下行信号所承载的信息，使得不造成干扰，使得使用该第一通信制式和该第二通信制式的不同基站和不同终端可以共享同一个带宽资源，而不会造成对使用第二通信制式的终端的干扰。
在一些可行的实施例中，该第一基站根据该码道信息和该第一调制符号确定受控子载 波的第二调制符号之后，还包括：确保该第一下行信号的功率小于或等于预设功率。
为了不浪费太多的功率，在根据所述码道信息和该第一调制符号确定受控子载波的第二调制符号之后，可以确保该第一下行信号的功率小于或等于预设功率，因而设置预设功率，以使得计算出来的目标载波发射时，其功率小于该预设功率，以使得当该第一基站使用该目标载波发送第一下行信号，且使用该第二通信制式的终端接收到该第一下行信号时，解扩解扰该第一下行信号后得不到或得到极少的信息，使得此类干扰非常小，因此使用该第一通信制式和该第二通信制式的不同基站和不同终端可以共享同一个带宽资源，从而实现无干扰或少干扰的通信。
在一些可行的实施例中，若该第一通信制式的基带采样频率小于该第二通信制式的基带采样频率，在该第一基站根据该码道信息和该第一调制符号确定受控子载波的第二调制符号之前，该第一基站还可以根据该第二通信制式的基带采样频率对OFDM的有用符号进行过采样，使得该第一通信制式的基带采样频率与该第二通信制式的基带采样频率相等。
在一些可行的实施例中，该第一基站和该第二基站可以为同一个基站，则该第一基站具备至少4个天线，其中，该4个天线用于发射该第一通信制式的信号，其中至少2个天线用于发射第二通信制式的信号。
在一些可行的实施例中，该第一基站获取使用该第一通信制式的第三基站在该目标载波中的第二调度子载波的第三调制符号；该第一基站根据该码道信息和该第一调制符号确定受控子载波的第二调制符号包括：该第一基站根据该第三调制符号、该第一调制符号和该码道信息确定该第二调制符号，以使得该第三调度子载波和该受控子载波所共同承载的第二下行信号与该OVSF码正交，该受控子载波与该第二调度子载波是不同的子载波，以使得多个第一通信制式的基站和一个第二通信制式的基站共享同一个频谱资源。
在一些可行的实施例中，该使用正交频分复用的通信制式包括长期演进技术LTE制式和新无线NR制式。
在一些可行的实施例中，该使用扩频码或扰码的通信制式包括通用移动通信系统UMTS制式和码分多址接入CDMA2000制式。
在一些可行的实施例中，该第一基站使用根升余弦滤波器。
本申请实施例的第二方面提供一种基站，其特征在于，包括：
获取模块，用于获取第二基站的码道信息，该码道信息包括该第二基站使用的正交可变扩频因子OVSF码和该第二基站所使用的扰码，该第一基站为使用正交频分复用OFDM的第一通信制式的基站，该第二基站为使用扩频码或扰码的第二通信制式的基站；确定模块，用于确定第一调度子载波的第一调制符号；计算模块，用于根据该码道信息和该第一调制符号计算受控子载波的第二调制符号，以使得该第一调度子载波和该受控子载波所共同承载的下行信号与该OVSF码正交，该受控子载波与该第一调度子载波是不同的子载波；发送模块，用于使用该第一调度子载波和该受控子载波发送该下行信号。
在一些可行的实施例中，该计算模块，还用于确保该第一下行信号的功率小于或等于预设功率。
在一些可行的实施例中，若该第一通信制式的基带采样频率小于该第二通信制式的基带采样频率，该基站还包括：采样模块，用于根据该第二通信制式的基带采样频率对OFDM 的有用符号进行过采样，使得该第一通信制式的基带采样频率与该第二通信制式的基带采样频率相等。
在一些可行的实施例中，该获取模块，还用于获取使用该第一通信制式的第三基站在该目标载波中的第二调度子载波的第三调制符号；该计算模块，还用于根据该第三调制符号、该第一调制符号和该码道信息计算该第二调制符号，以使得该第三调度子载波和该受控子载波所共同承载的第二下行信号与该OVSF码正交，该受控子载波与该第二调度子载波是不同的子载波。
本申请实施例的第三方面提供了一种基站，其特征在于，包括：收发器、处理器和存储器；该收发器，用于获取第二基站的码道信息，该码道信息包括该第二基站使用的正交可变扩频因子OVSF码和该第二基站所使用的扰码，该第一基站为使用正交频分复用OFDM的第一通信制式的基站，该第二基站为使用扩频码或扰码的第二通信制式的基站；该处理器，用于确定第一调度子载波的第一调制符号，根据该码道信息和该第一调制符号确定受控子载波的第二调制符号，以使得该第一调度子载波和该受控子载波所共同承载的下行信号与该OVSF码正交，该受控子载波与该第一调度子载波是不同的子载波；该收发器，还用于使用该第一调度子载波和该受控子载波发送该下行信号；该存储器，用于存储程序、该码道信息、该第一调度子载波的第一调制符号和该受控子载波的第二调制符号。
本申请的又一方面提供了一种计算机可读存储介质，所述计算机可读存储介质中存储有指令，当其在计算机上运行时，使得计算机执行上述各方面所述的方法。
本申请实施例提供的技术方案中，该第一基站为使用正交频分复用OFDM的第一通信制式的基站，该第二基站为使用扩频码或扰码的第二通信制式的基站，第一基站可以获取第二基站的码道信息并确定第一调度子载波的第一调制符号，该码道信息包括该第二基站使用的正交可变扩频因子OVSF码和该第二基站所使用的扰码，之后，可以根据该码道信息和该第一调制符号确定受控子载波的第二调制符号，以使得当该第一基站使用该第一调度子载波和该受控子载波发送该下行信号时，由于第一调度子载波所承载的下行信号内的信息是发送给使用该第一通信制式的终端的，对于使用第二通信制式的终端来说是干扰信号，该第一调度子载波和该受控子载波所共同承载的下行信号与该OVSF码正交，因此当使用第二通信制式的终端接收到该下行信号并解扩解扰后，使用第二通信制式的终端将会得不到该下行信号所承载的信息，使得不造成干扰，使得使用该第一通信制式和该第二通信制式的不同基站和不同终端可以共享同一个带宽资源，而不会造成对使用第二通信制式的终端的干扰。
附图说明
图1为本申请中一种下行信号发送方法的一个实施例示意图；
图2为本申请中一种下行信号发送方法的一个实施例示意图；
图3为UMTS的扩频码的取值方式示意图；
图4为OFDM有用符号与UMTS扩频码在时间上的对应关系的示意图；
图5为有用OFDM符号与UMTS使用的等效的OVSF码的示意图；
图6为3MHz系统带宽的LTE与5MHz的UMTS信号的功率谱密度的示意图；
图7为5MHz的LTE系统与UMTS的UE的接收滤波器的示意图；
图8为多个非第二通信制式与第二通信制式共享频谱的示意图；
图9为一种基站900的一个实施例示意图；
图10为一种基站900的另一个实施例示意图。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。
本申请的说明书和权利要求书及上述附图中的术语“第一”、“第二”、“第三”、“第四”等(如果存在)是用于区别类似的对象，而不必用于描述特定的顺序或先后次序。应该理解这样使用的数据在适当情况下可以互换，以便这里描述的实施例能够以除了在这里图示或描述的内容以外的顺序实施。此外，术语“包括”和“具有”以及他们的任何变形，意图在于覆盖不排他的包含，例如，包含了一系列步骤或单元的过程、方法、系统、产品或设备不必限于清楚地列出的那些步骤或单元，而是可包括没有清楚地列出的或对于这些过程、方法、产品或设备固有的其它步骤或单元。
请参考图1，为本申请实施例中的系统结构，包括基站和多个终端，其中，多个终端中包括使用第一通信制式的和使用第二通信制式的，本申请实施例中，第一通信制式以UMTS为例进行说明，第二通信制式以LTE为例进行说明。
本申请实施例中的基站，也可称为基站设备，是一种部署在无线接入网用以提供无线通信功能的设备。在不同的无线接入系统中基站的叫法可能有所不同，例如在通用移动通讯系统(Universal Mobile Telecommunications System，UMTS)网络中基站称为节点B(NodeB),而在LTE网络中的基站称为演进的节点B(evolved NodeB，eNB或者eNodeB)，在新空口(new radio,NR)网络中的基站称为收发点(transmission reception point，TRP)或者下一代节点B(generation nodeB，gNB)，或者在其他多种技术融合的网络中，或者在其他各种演进网络中的基站也可能采用其他叫法。本发明并不限于此。
终端，又称之为用户设备，是一种向用户提供语音和/或数据连通性的设备，例如，具有无线连接功能的手持式设备、车载设备等。常见的终端例如包括：手机、平板电脑、笔记本电脑、掌上电脑、移动互联网设备(mobile internet device，MID)、可穿戴设备，例如智能手表、智能手环、计步器等。
需要说明的是，在5G时代中，物联网终端密度可能比现有手机密度高出10倍，也即人均拥有10个联网终端，汽车、自行车、空调、灯具、窗帘、门锁、电表、手表、衣帽、音响、行李箱都可能实现联网，快递也会实现实时查看，工业机器人通过网络进行配置等，物联网将成为改变人们生活的最大亮点。与此同时，5G的终端的基带芯片计算能力更强，基带的提升也即手机核心处理器的提升，基带芯片包括CPU处理器、信道编码器、数字信号处理器、调制解调器和接口模块，先进编码调制对信道编码器提出了要求；新型多址、新型多载波对调制解调器提出了要求；大规模MIMO、全双工、高频段通信、超密集组网由于提升了数据量，对整个芯片都提出了要求。5G的终端的天线更加多元，除了目前的双天线，多天线技术会出现，同时，高频段小尺寸天线也会集成在手机之中。
在本系统架构中，基站可以同时具备多种通信制式的功能，即具备同时服务使用多种通信制的终端的能力，例如，基站可以通知具备UMTS和LTE的功能，可以同时服务使用UMTS和LTE的终端的能力。
随着移动通信产业的发展，用户逐渐从旧的通信系统向新的通信系统迁移，因此旧的通信系统的频谱越来越空闲，新的通信系统的频谱越来越紧张。但是由于旧的通信系统还是有人用的，不能马上关闭，当下可以通过频谱共享来解决这个问题，即同一段频谱服务两个或多个通信系统。
以UMTS系统和LTE系统为例，如果某段时间UMTS系统的业务量低而LTE系统的业务量高，那么UMTS系统就去激活某个或某几个载波，UMTS去激活的载波就留给LTE系统使用；如果某段时间UMTS系统的业务量高而LTE系统的业务量低，那么就LTE就去激活某个或某几个载波，LTE去激活的载波就留给UMTS系统使用。由于UMTS系统对LTE系统或NR系统让出频谱必须以5MHz为单位，这时，如果UMTS系统只剩下一个5MHz的载波，则无法继续让出该5MHz。
在本申请实施例中，以第一基站为使用正交频分复用的第一通信制式(如LTE或NR)的基站，第二基站为使用扩频码或扰码的第二通信制式(如UMTS)的基站，当第一基站使用目标载波发送下行信号时，目标载波中的第一调度子载波所承载的下行信号内的信息是发送给使用该第一通信制式的终端的，对于使用第二通信制式的终端来说是干扰信号，由于该目标载波还包括不同于该第一调度子载波的受控子载波，该受控子载波的第二调制符号是根据第一调度子载波的第一调制符号、第二基站使用的正交可变扩频因子OVSF码和所述第二基站所使用的扰码确定的，且所述第一调度子载波和所述受控子载波所共同承载的下行信号与所述OVSF码正交的，因此，当使用第二通信制式的终端接收到该下行信号并解扩解扰后，使用第二通信制式的终端将会得不到该下行信号所承载的信息，使得不造成干扰，使得使用该第一通信制式和该第二通信制式的不同基站和不同终端可以共享同一个带宽资源，而不会造成对使用第二通信制式的终端的干扰。
为便于理解，下面对本申请实施例中的具体流程进行描述，请参阅图2，本申请中一种下行信号发送方法的一个实施例包括：
201、第一基站获取第二基站的码道信息。
在本申请实施例中，第一基站可以预先获取第二基站的码道信息，该码道信息包括该第二基站使用的正交可变扩频因子OVSF码和该第二基站所使用的扰码。需要说明的是，第一基站为使用正交频分复用OFDM的第一通信制式的基站，该第二基站为使用扩频码或扰码的第二通信制式的基站。
在本申请实施例中，第一通信制式为使用正交频分复用(Orthogonal Frequency Division Multiplexing，OFDM)的通信制式，该第一通信制式是多载波调制(Multi-CarrierModulation，MCM)中的一种。在MCM技术中，把数据流分解为若干个子数据流，从而使子数据流具有低得多的传输比特速率，利用这些数据分别去调制若干个子载波。在使用该MCM技术的该第一通信制式下，将信道分成若干正交子信道，将高速数据信号转换成并行的低速子数据流，调制到在每个子信道上进行传输，正交信号可以通过在接收端采用相关技术来分开，这样可以减少子信道之间的相互干扰，每个子信道上的信号带宽小于信道的相关带宽， 因此每个子信道上的可以看成平坦性衰落，从而可以消除符号间干扰，而且由于每个子信道的带宽仅仅是原信道带宽的一小部分，信道均衡变得相对容易。
在本申请实施例中，该第一通信制式可以包括长期演进技术(Long Term Evolution，LTE)的通信制式和新无线NR的通信制式。其中，LTE是由第三代合作伙伴计划(The 3rd Generation Partnership Project，3GPP)组织技术标准的长期演进，LTE系统引入了OFDM和多输入多输出(Multi-Input&Multi-Output，MIMO)等关键技术，显著增加了频谱效率和数据传输速率。而且该LTE系统支持多种带宽分配：1.4MHz，3MHz，5MHz，10MHz，15MHz和20MHz等，且支持全球主流2G/3G频段和一些新增频段，因而频谱分配更加灵活，系统容量和覆盖也显著提升。
在本申请实施例中，该第二基站为使用扩频码或扰码的第二通信制式的基站，如通用移动通信系统(Universal Mobile Telecommunications System，UMTS)制式和码分多址接入(Code Division Multiple Access 2000，CDMA2000)制式，其中，CDMA2000是数字移动通信进程中出现的一种无线扩频通信技术，具有频谱利用率高、话音质量好、保密性强、掉话率低、电磁辐射小、容量大、覆盖广等特点。
在本申请实施例中，扩频码又称为信道化码，用于区分来自同一小区的不同传输连接，从下行信号看，扩频码用于区别一个小区的不同链路连接。
在一些可行的实施例中，第一基站和第二基站可以为同一个基站，也可以为不同的基站。若为同一个基站，则可以分别使用不同的天线用于分别发送第一通信制式和第二通信制式的信号，此处不做限定。
若第一基站和第二基站为同一个基站，当需要共站发射的第一通信制式和第二通信制式分别有不同的发射天线数时的处理方法，不同的通信制式使用不同的数目的发射天线发射出去，发射天线数小的制式的信号被复制几份占满发射天线数多的制式使用的天线。例如，第一通信制式在四个天线发，其中包括第二通信制式的两个天线a和b，于是第一基站(或第二基站)在分别发a/sqrt(2)，a/sqrt(2)，b/sqrt(2)，b/sqrt(2)，也可以分别发a，b/sqrt(3)，b/sqrt(3)，b/sqrt(3)，还可以发a/sqrt(3)，a/sqrt(3)，a/sqrt(3)，b，此处不做限定。(sqrt系Square Root Calculations，即平方根计算)
在本申请实施例中，若第二通信制式为UMTS，该第二基站发送的下行信号是不同物理信道的信号的叠加，除SCH(包括P-SCH和S-SCH)以外的物理信道应用小区特定的扰码，即一个小区的不同物理信道使用相同的扰码，和不同的OVSF码(扩频码)，这些物理信道通常被叫做不同的码道。如UMTS系统中使用的扩频码按照图3(为UMTS的扩频码的取值方式示意图)所示的方法取值，扩频码的序列中每个元素的取值为1或-1，其中，下行使用的扰码长度为38400码片，对应10ms的无线帧长，扰码序列的每个元素为模为1的复数。
202、该第一基站确定第一调度子载波的第一调制符号。
在本申请实施例中，当第一基站需要向使用第一通信制式的终端发行下行信号时，可以根据相关协议确定目标载波中的第一调度子载波及其第一调制符号，该第一调度子载波为用于承载向使用第一通信制式的终端发送下行信号的子载波，以确定当该第一基站使用该目标载波发送下行信号时，该第一通信制式的终端可以接收到相关的信息。
203、该第一基站根据该码道信息和该第一调制符号确定受控子载波的第二调制符号。
在本申请实施例中，当获取了第二基站的码道信息和确定了第一调度子载波的第一符号后，可以通过计算确定该受控子载波的第二调度符号，该受控子载波与该第一调度子载波是不同的子载波，以使得该第一调度子载波和该受控子载波所共同承载的下行信号与该OVSF码正交。
在一些可行的实施例中，若第一通信制式是LTE或NR，第二通信制式是UMTS，LTE或NR的基带采样频率和UMTS的基带采样频率的大小关系的不同，可以导致其计算方法的不同。
需要说明的是，一个基站中的基带处理单元(Base band Unit，BBU)与射频拉远单元(Radio Remote Unit，RRU)之间的接口是公共无线电(Common Public Radio Interface，CPRI)接口，通过该CPRI接口传递基带信号采样。UMTS下行的CPRI接口的采样频率为3.84MHz，基带信号采样通过CPRI到RRU后，经过处理(例如上变频等)变为射频信号通过天线发射出去。
而作为4G的LTE系统分为时分双工(Time Division Duplexing，TDD)和频分双工(Frequency Division Duplexing，FDD)，不同于UMTS的下行信号是由不同码道的信号的叠加，LTE的下行信号是不同频率的子载波信号的叠加，不同系统带宽的LTE系统有不同的CPRI接口速率，见表1，LTE的子载波间隔Δf＝15kHz。一个有用OFDM符号的持续时间为
Figure PCTCN2017118820-appb-000001
该持续时间等于UMTS里的256个码片的持续时间，因为
Figure PCTCN2017118820-appb-000002
LTE基带信号的采样频率等于FFT点数与子载波间隔的乘积。容易知道，LTE的一个有用OFDM符号被采样成“FFT点数”个采样点。需要说明的是，实际系统中的采样频率可以高于表1中的数值，也就是过采样，LTE系统也可以部署多个载波，其中每个载波的带宽在表1中选取(按照协议，多个载波的带宽的选取在不同的频段会有不同的限制，不是从表中任意选取)，表1中的“FFT点数”是产品实现一般会采用的数值，采用其他数值也可以。
表1：不同系统带宽的LTE系统的有关参数
Figure PCTCN2017118820-appb-000003
一、LTE或NR的基带采样频率等于UMTS的基带采样频率。
在一些可行的实施例中，当LTE或NR的基带采样频率等于UMTS的基带采样频率时，即如表1所示的系统带宽为3MHz的LTE系统的基带信号采样频率等于UMTS的基带采样频率3.84MHz。为了简单起见，下面以3MHz的LTE系统为例描述具体算法，该描述可照 搬到有相同采样频率的NR系统中。
LTE系统中的一个有用OFDM符号的起始时刻与UMTS系统中的一个符号的起始时刻不一定相同，为了对计算方式方便解释，我们假设该有用OFDM符号和UMTS系统中的一个符号如图4(OFDM有用符号与UMTS扩频码在时间上的对应关系的示意图)所示的两者相同的场景。在本申请实施例中，轻载的UMTS下行使用了公共信道P-CPICH和P-CCPCH，它们使用SF＝256的OVSF码，如图4中所用的C_(ch,256,n)(n＝0,1)来表示OVSF码如图3所示，其中，n表示OVSF码的序号，这与技术规范中的记号一致。假设基站除了发送这两个公共信道，还发送其他使用SF＝128的信道，例如，发向特定UE的专用信道DPCH，在DPCH上传R99业务，例如AMR12.2k的语音业务。
在本申请实施例中，图4中标P-CPICH的长条对应P-CPICH的一个符号的持续时间，该符号被SF为256的OVSF码扩频，每个符号被扩展成256个码片，这个持续时间正好等于OFDM有用符号的持续时间，标“SF128，e.g.,R99etc.”的两个长条对应使用SF为128的OVSF码扩频的信道的两个符号的持续时间，每个符号被扩展成128个码片，两个符号正好是256个码片，总的持续时间等于一个OFDM有用符号的持续时间。
以下为具体的计算方法：
1、设值。
假设第一基站从目标载波(5MHz)中选择N 1个子载波作为第一调度子载波，它们对应的快速傅里叶逆变换IFFT索引(从1开始计数)的集合记为K 1，该第一调度子载波的第一调制符号构成的N 1×1的列向量记为s，然后，从LTE中的该目标载波中该调度子载波之外的不使用的子载波中选择一部分作为受控子载波。需要说明的是，受控子载波可以是当前没有调度的子载波，也可以是保护带上的子载波，此处不做限定。再假设受控子载波个数为N 2，它们对应的IFFT索引(从1开始计数)的集合记为K 2，这些子载波上所传的调制符号构成的N 1×1的列向量记为x。
2、计算。
令G为L×L的归一化的离散傅里叶逆变换IDFT矩阵，本申请实施例中，以系统带宽为3MHz为例，则其FFT点数为256，即L为256，则G的第m(1≤m≤256)行第n(1≤n≤256)列的元素为
Figure PCTCN2017118820-appb-000004
其中，j是虚数单位。
然后，只保留G中列的索引(从1开始计数)为集合K 1的元素的那些列，删掉G的其余列，所得的256×N 1的矩阵记为T；只保留G中列的索引(从1开始计数)为集合K 2的元素的那些列，删掉G的其余列，所得的256×N 2的矩阵记为R，则可以得到LTE系统的正交频分复用OFDM的有用符号的采样构成的256×1的列向量：
g＝Ts+Rx(1)
记S为256×256的对角矩阵，其对角线元素为在这256个码片的持续时间内扰码的取值，记OVSF码C ch,256,n(n＝0,1)构成的256×1的列向量为u n，记OVSF码C ch,128,k构成的128×1的列向量为v k。
令(2M+2)×256的矩阵：
Figure PCTCN2017118820-appb-000005
UMTS系统中的终端对收到的LTE系统的信号解扰解扩完后得到的(2M+2)个符号(其中两个符号的SF为256，其余的2M个符号的SF为128)设为的(2M+2)×1的列向量：
r＝AS Hg(3)
令x＝r，得到该受控子载波的第二调制符号x。
3、功率优化。
需要说明的是，在本申请实施例中，为了不浪费太多的功率，在根据所述码道信息和该第一调制符号确定受控子载波的第二调制符号之后，可以确保该第一下行信号的功率小于或等于预设功率，因而设置预设功率，以使得计算出来的目标载波发射时，其功率小于该预设功率，以使得当该第一基站使用该目标载波发送第一下行信号，且使用该第二通信制式的终端接收到该第一下行信号时，解扩解扰该第一下行信号后得不到或得到极少的信息，使得此类干扰非常小，因此使用该第一通信制式和该第二通信制式的不同基站和不同终端可以共享同一个带宽资源，从而实现无干扰或少干扰的通信。
设
Figure PCTCN2017118820-appb-000006
为满足预设功率P的受控子载波的第二调制符号x。
我们希望选取合适的x最小化UMTS的终端看到的LTE的干扰的功率，即最小化：
||r|| 2(4)
其中，||·||表示向量的欧式范数。
最小化式(4)时，还需要给出约束条件：
||x|| 2≤P(5)
即UMTS的额外使用的码道功率不超过预设功率P。
根据式(1)和式(3)得到公式：
Figure PCTCN2017118820-appb-000007
令：
K＝AS HR(7)
b＝-AS HTs(8)
那么上述优化问题简化为：
Figure PCTCN2017118820-appb-000008
由卡罗需-库恩-塔克条件(Karush-Kuhn-Tucker Conditions，KKT)得到：
Figure PCTCN2017118820-appb-000009
如果λ＞0，那么：
||x|| 2＝P(11)
(K HK+λI)x＝K Hb(12)
解得：
Figure PCTCN2017118820-appb-000010
其中，λ 0使得
Figure PCTCN2017118820-appb-000011
满足式(11)，I是单位矩阵，λ 0越大，
Figure PCTCN2017118820-appb-000012
的范数就越小，通过二分查找可以找到最佳的λ 0。
如果λ＝0，那么：
K HKx＝K Hb(14)
可知x是：
Kx＝b(15)
的最小二乘解。
实际应用时为了简化计算，直接令λ为某一个固定的值，此处不做限定，例如λ＝0.01，然后按照式(13)计算得到
Figure PCTCN2017118820-appb-000013
至此，我们得到一个算法获得受控子载波上的调制符号取值，在满足受控子载波消耗功率的前提下使得UTMS的终端解扰解扩后看到的来自LTE的干扰功率尽可能小。根据上述方式确定该目标载波中的受控子载波的第二调制符号，并使用该目标载波发送下行信号，由于该第一调度子载波的下行信号内的信息是发送给使用该第一通信制式的终端的，对于使用第二通信制式的终端来说是干扰信号，由于使用第二通信制式的终端接收到该下行信号并解扩解扰后，得不到或者得到极少的信息，使得此类干扰非常小，因此使用该第一通信制式和该第二通信制式的不同基站和不同终端可以共享同一个带宽资源，从而实现无干扰或少干扰的通信。
二、LTE或NR的基带采样频率小于UMTS的基带采样频率。
在一些可行的实施例中，当LTE或NR的基带采样频率小于UMTS的基带采样频率时，可以对LTE或NR进行过采样，以使其采样频率等于UMTS的采样频率，然后上述“一、”的处理过程。在LTE或NR技术中，一种过采样的方法是进行点数更大的IFFT，例如，对于1.4MHz的LTE系统进行通常的128点的FFT和IFFT，而是像3MHz的LTE系统那样进行256点的快速傅里叶变换FFT和快速傅里叶逆变换IFFT，此处不再赘述。
三、LTE或NR的基带采样频率大于UMTS的基带采样频率。
在本申请实施例中，当LTE或NR的系统带宽为5MHz、10MHz、15MHz和20MHz时，LTE的基带信号采样频率大于UMTS的基带采样频率，这时LTE或NR的信号占用的带宽会大于UMTS的RRC滤波器的带宽，即UMTS的终端的RRC滤波器会影响LTE信号，则可以使用以下方式进行计算：
1、设值。
此处的设置方式与“一、”中的设值方式一致，此处不再赘述。
2、计算。
令G’为L’×L′(L’为第一基站所使用的IFFT点数，见表1)的归一化的离散傅里叶逆变换IDFT矩阵，其中L’＞L)，G的第m(1≤m≤L′)行第n(1≤n≤L′)列的元素为
Figure PCTCN2017118820-appb-000014
其中，j是虚数单位。
然后，只保留G中列的索引(从1开始计数)为集合K 1的元素的那些列，删掉G的其余列，所得的L′×N 1的矩阵记为T；只保留G中列的索引(从1开始计数)为集合K 2的元素的那些列，删掉G的其余列，所得的L′×N 2的矩阵记为R，OFDM有用符号的采样构成的L’×1的列向量：
g＝Ts+Rx(17)
因为L′＞L，所以采样频率大于3.84MHz，第一基站发送LTE信号时，并没有像第二基站那样加RRC滤波器，而该下行信号经过第二通信制式的终端时会经过其终端的接收滤波器(为RRC滤波器)，根据3GPP的协议TS25.104中的6.8.1小节规定了UMTS使用的RRC滤波器的单位冲激响应：
Figure PCTCN2017118820-appb-000015
其中，式中的T c≈0.26μs为UMTS的码片持续时间，滚降系数α＝0.22。由于LTE信号的采样间隔为
Figure PCTCN2017118820-appb-000016
因此，将RRC滤波器离散化后得到数字滤波器的单位脉冲响应
Figure PCTCN2017118820-appb-000017
其中，h(n)仅在有限的长度内有显著非0的取值。
为了简化计算，可以将h(n)截短为长度2F+1，该下行信号经过第二通信制式的终端的接收滤波器就是信号采样与h(n)进行线性卷积。此处只考虑有用OFDM符号g与h(n)线性卷积，线性卷积后去掉开始的F个数值，从第F+1个数值开始往后的L’个数值组成L′×1的向量g′，用矩阵运算表示为：
g′＝Hg＝HTs+HRx(19)
其中，L′×L′的矩阵H由h(-F)、h(-F+1)、……、h(F)构成。
第二通信制式的终端会按照处理接收到的下行信号的方式处理收到的该下行信号，对g′进行降采样，降采样因子为L′/256，即取出每L′/256个数值中的第一个值，这里假设L′/256为整数，降采样后得到256×1的向量g″，其中，g″可用矩阵运算表示为：
g″＝Λg′＝ΛHTs+ΛHRx(20)
其中，Λ的元素为0或1，如果是由采样频率7.68MHz(L′＝512)的序列降采样到采样频率为3.84MHz的序列(降采样因子为2)，那么：
Figure PCTCN2017118820-appb-000018
在矩阵中，每一行的1都比上一行向右移动两列，Λ乘以一个列向量就相当于将列向量的第1、3、5、7、……个元素取出来重新排成一个列向量，就是每两个元素中抽取第一个元素，则式(20)中的g″与式(1)中的g有类似的表达式，后续的计算方式可以参照上述的“一、”中的计算方法，此处不再赘述。
3、功率优化。
此处的设置方式与“一、”中的功率优化方式一致，此处不再赘述。
另外，需要说明的是，由于LTE的有用OFDM符号与UMTS的符号的在时间上并不总是对齐，事实上，在1ms内14个有用OFDM符号中只有1个有用OFDM符号与UMTS的符号的对齐。这将导致误差，完全精确的方法是统一优化1ms内14个OFDM符号的受控子载波的取值，但这导致复杂度变大，如果需要避开的码道个数比较多，那么本实施例提供的方法能够仍然按每个OFDM符号优化受控子载波的取值，复杂度上升并不明显。
如图5(为有用OFDM符号与UMTS使用的等效的OVSF码的示意图)所示，一个SF＝N(N≥2)的OVSF码能够衍生出两个SF＝2N(N≥2)的OVSF码，且这两个SF＝2N的OVSF码都被使用，那么我们可以认为衍生这两个OVSF码的那个SF＝N的OVSF码被使用。如图5中的UMTS使用了SF＝256的OVSF码和若干SF＝128的OVSF码，如果这些OVSF码在如图3所示的码树上的排列有规律，那么可以认为UMTS使用了若干SF＝64(甚至SF更小，例如SF＝32)的OVSF码，则没有将有用OFDM符号的起始时刻与UMTS的符号的起始时刻对齐，这样更有一般性。
该方法在UMTS使用的OVSF码在码树上排列有规律时，能够提高性能(也就是使UTMS的终端受到来自LTE或NR的干扰更小)，并且不显著增加复杂度。
选取受控子载波使OFDM的时域信号在图5所示的时间段B、C、D上与OVSF码
Figure PCTCN2017118820-appb-000019
……、
Figure PCTCN2017118820-appb-000020
正交，在时间段A和E上OFDM信号的取值没有与对应的OVSF码正交，这会对UMTS信号造成干扰。即使这样，该方法比上述描述的方法始终假设Δ＝0能获得更好的性能(即对UMTS造成的干扰更小)。事实上，当等效的OVSF码的SF(该例中是64)足够小时，时间段A与E所占的比例就小，由此造成的干扰可接受。
结合以下例子进行说明，本例是UMTS与5MHz的LTE共享下行频谱，5MHz的LTE系统的基带采样率为7.68MHz大于UMTS的基带采样频率3.84MHz，该LTE系统的子载波与UMTS的终端的接收滤波器如图6所示(为3MHz系统带宽的LTE与5MHz的UMTS信号的功率谱密度的示意图)。图6中的“DC”表示直流子载波，协议规定不使用该子载波，图6中所标的UMTS的子载波是在LTE的保护带并且落进UMTS的终端的接收带宽内的子载波，在该例中，调度的子载波在DC附近，而受控子载波包括一部分不调度的子载波和保护带上的子载波。在本申请实施例中，调度的子载波传输发向LTE的终端的数据，而受控子载波根据上述方法取值。受控子载波的取值与调度的子载波的取值和要“避开”的UMTS的码道以及UTMS使用的扰码有关。
由于受控子载波的存在，LTE的波形被改变，改变的结果就是UMTS的终端在解扰解扩它需要的码道时看不到(仅理想情况下)LTE的信号。需要说明的是，受控子载波本来不该发送数据，应用本申请后发送了某些特定取值的数据，本实施例通过受控子载波使得LTE与UMTS信号近似正交，UMTS的终端在解扰解扩某一条径上的UMTS信号时，与该UMTS信号时延相同的(例如也在该条径上)LTE信号对该UMTS信号不造成干扰。
由于该第一调度子载波的下行信号内的信息是发送给使用该第一通信制式的终端的，对于使用第二通信制式的终端来说是干扰信号，由于使用第二通信制式的终端接收到该下行信号并解扩解扰后，得不到或者得到极少的信息，使得此类干扰非常小，因此使用该第一通信制式和该第二通信制式的不同基站和不同终端可以共享同一个带宽资源，从而实现无干扰或少干扰的通信。
204、该第一基站使用该第一调度子载波和该受控子载波发送该下行信号。
在本申请实施例中，当确定了受控子载波的第二调制符号后，可以使用该第一调度子 载波和该受控子载波发送下行信号，则使得使用第一通信制式的终端和使用第二通信制式的终端均可接收到下行信号。由于该第一调度子载波的下行信号内的信息是发送给使用该第一通信制式的终端的，对于使用第二通信制式的终端来说是干扰信号，由于使用第二通信制式的终端接收到该下行信号并解扩解扰后，得不到或者得到极少的信息，使得此类干扰非常小，因此使用该第一通信制式和该第二通信制式的不同基站和不同终端可以共享同一个带宽资源，从而实现无干扰或少干扰的通信。
在一些可行的实施例中，第一基站可以使用根升余弦滤波器作为发射滤波器，以便与第二基站(指UMTS)共用发射模块。
图7(为5MHz的LTE系统与UMTS的UE的接收滤波器的示意图)中比较了3MHz系统带宽的LTE与5MHz的UMTS信号的功率谱密度，LTE的PSD在0频率处有个下降尖峰是因为LTE在DC子载波上没有传数据。UMTS的接收滤波器和发射滤波器的幅频响应的模的平方与UMTS信号的PSD有相同的形状。从图7中可以看到，UMTS接收滤波器对3MHz系统带宽的LTE信号的影响较小，因为在滤波器幅频响应从水平开始下降的频点上LTE信号的PSD已经下降了大约30dB。
在一些可行的实施例中，当第一基站和第二基站为同一个基站而共站发射时，可以在带宽较小的LTE或带宽较小并且不采用发射滤波器的NR的发射端也加一个与UMTS一样的发射滤波器，允许小带宽的LTE(例如3MHz的系统带宽)或NR也加一个发射滤波器意味着LTE或NR基带信号可以与UMTS的基带信号先叠加然后经过同一个RRU发射出去，这能够降低成本。
需要说明的是，在一些可行的实施例中，如图8(为多个非第二通信制式与第二通信制式共享频谱的示意图)，图8中非第二通信制式有可能指同一个通信制式，也可能指不同的通信制式，此处不做限定。在一些可行的实施例中，非第二通信制式所占的频率范围根据需要也可以比5MHz稍微大一些，图8右边的省略号表示中间还可以并排放置更多的非第二通信制式，每个非第二通信制式都有受控子载波，基站确定受控子载波时要综合考虑多种通信制式，此处不做限定。
以上对一种下行信号发送的方法进行了描述，以下对相关的基站进行描述，请参考图9，为一种基站900，包括：
获取模块901，用于获取第二基站的码道信息，该码道信息包括该第二基站使用的正交可变扩频因子OVSF码和该第二基站所使用的扰码，该第一基站为使用正交频分复用OFDM的第一通信制式的基站，该第二基站为使用扩频码或扰码的第二通信制式的基站。
确定模块902，用于确定第一调度子载波的第一调制符号。
计算模块903，用于根据该码道信息和该第一调制符号计算受控子载波的第二调制符号，以使得该第一调度子载波和该受控子载波所共同承载的下行信号与该OVSF码正交，该受控子载波与该第一调度子载波是不同的子载波。
发送模块904，用于使用该第一调度子载波和该受控子载波发送该下行信号。
由于第一调度子载波所承载的下行信号内的信息是发送给使用该第一通信制式的终端的，对于使用第二通信制式的终端来说是干扰信号，该第一调度子载波和该受控子载波所共同承载的下行信号与该OVSF码正交，因此当使用第二通信制式的终端接收到该下行信 号并解扩解扰后，使用第二通信制式的终端将会得不到该下行信号所承载的信息，使得不造成干扰，使得使用该第一通信制式和该第二通信制式的不同基站和不同终端可以共享同一个带宽资源，而不会造成对使用第二通信制式的终端的干扰。
在一些可行的实施例中，该计算模块902，还用于确保该第一下行信号的功率小于或等于预设功率。
在一些可行的实施例中，若该第一通信制式的基带采样频率小于该第二通信制式的基带采样频率，该基站900还包括：
采样模块905，用于根据该第二通信制式的基带采样频率对OFDM的有用符号进行过采样，使得该第一通信制式的基带采样频率与该第二通信制式的基带采样频率相等。
在一些可行的实施例中，该获取模块901，还用于获取使用该第一通信制式的第三基站在该目标载波中的第二调度子载波的第三调制符号。
该计算模块903，还用于根据该第三调制符号、该第一调制符号和该码道信息计算该第二调制符号，以使得该第三调度子载波和该受控子载波所共同承载的第二下行信号与该OVSF码正交，该受控子载波与该第二调度子载波是不同的子载波。
上面从模块化功能实体的角度对本申请实施例进行描述，下面从硬件处理的角度对本申请实施例进行描述，请参阅图10，本申请实施例提供了一种基站1000：
收发器1001、处理器1002和存储器1003。
该收发器1001，用于获取第二基站的码道信息，该码道信息包括该第二基站使用的正交可变扩频因子OVSF码和该第二基站所使用的扰码，该第一基站为使用正交频分复用OFDM的第一通信制式的基站，该第二基站为使用扩频码或扰码的第二通信制式的基站。
该处理器1002，用于确定第一调度子载波的第一调制符号，根据该码道信息和该第一调制符号确定受控子载波的第二调制符号，以使得该第一调度子载波和该受控子载波所共同承载的下行信号与该OVSF码正交，该受控子载波与该第一调度子载波是不同的子载波
该收发器1001，还用于使用该第一调度子载波和该受控子载波发送该下行信号。
该存储器1003，用于存储程序、该码道信息、该第一调度子载波的第一调制符号和该受控子载波的第二调制符号。
由于第一调度子载波所承载的下行信号内的信息是发送给使用该第一通信制式的终端的，对于使用第二通信制式的终端来说是干扰信号，该第一调度子载波和该受控子载波所共同承载的下行信号与该OVSF码正交，因此当使用第二通信制式的终端接收到该下行信号并解扩解扰后，使用第二通信制式的终端将会得不到该下行信号所承载的信息，使得不造成干扰，使得使用该第一通信制式和该第二通信制式的不同基站和不同终端可以共享同一个带宽资源，而不会造成对使用第二通信制式的终端的干扰。
在上述实施例中，可以全部或部分地通过软件、硬件、固件或者其任意组合来实现。当使用软件实现时，可以全部或部分地以计算机程序产品的形式实现。
所述计算机程序产品包括一个或多个计算机指令。在计算机上加载和执行所述计算机程序指令时，全部或部分地产生按照本申请实施例所述的流程或功能。所述计算机可以是通用计算机、专用计算机、计算机网络、或者其他可编程装置。所述计算机指令可以存储在计算机可读存储介质中，或者从一个计算机可读存储介质向另一计算机可读存储介质传 输，例如，所述计算机指令可以从一个网站站点、计算机、服务器或数据中心通过有线(例如同轴电缆、光纤、数字用户线(DSL))或无线(例如红外、无线、微波等)方式向另一个网站站点、计算机、服务器或数据中心进行传输。所述计算机可读存储介质可以是计算机能够存储的任何可用介质或者是包含一个或多个可用介质集成的服务器、数据中心等数据存储设备。所述可用介质可以是磁性介质，(例如，软盘、硬盘、磁带)、光介质(例如，DVD)、或者半导体介质(例如固态硬盘Solid State Disk(SSD))等。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，上述描述的系统，装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统，装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。上述集成的单元既可以采用硬件的形式实现，也可以采用软件功能单元的形式实现。
所述集成的单元如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的全部或部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行本申请各个实施例所述方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、只读存储器(ROM，Read-Only Memory)、随机存取存储器(RAM，Random Access Memory)、磁碟或者光盘等各种可以存储程序代码的介质。
以上所述，以上实施例仅用以说明本申请的技术方案，而非对其限制；尽管参照前述实施例对本申请进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本申请各实施例技术方案的精神和范围。

Claims (15)

  1. 一种下行信号发送方法，其特征在于，包括：
    第一基站获取第二基站的码道信息，所述码道信息包括所述第二基站使用的正交可变扩频因子OVSF码和所述第二基站所使用的扰码，所述第一基站为使用正交频分复用OFDM的第一通信制式的基站，所述第二基站为使用扩频码或扰码的第二通信制式的基站；
    所述第一基站确定第一调度子载波的第一调制符号；
    所述第一基站根据所述码道信息和所述第一调制符号确定受控子载波的第二调制符号，以使得所述第一调度子载波和所述受控子载波所共同承载的下行信号与所述OVSF码正交，所述受控子载波与所述第一调度子载波是不同的子载波；
    所述第一基站使用所述第一调度子载波和所述受控子载波发送所述下行信号。
  2. 根据权利要求1述方法，其特征在于，所述第一基站根据所述码道信息和所述第一调制符号确定受控子载波的第二调制符号之后，还包括：
    确保所述第一下行信号的功率小于或等于预设功率。
  3. 根据权利要求1或2所述方法，其特征在于，若所述第一通信制式的基带采样频率小于所述第二通信制式的基带采样频率，所述第一基站根据所述码道信息和所述第一调制符号确定受控子载波的第二调制符号之前，还包括：
    所述第一基站根据所述第二通信制式的基带采样频率对OFDM的有用符号进行过采样，使得所述第一通信制式的基带采样频率与所述第二通信制式的基带采样频率相等。
  4. 根据权利要求1-3中任一项所述方法，其特征在于，所述第一基站和所述第二基站为同一个基站。
  5. 根据权利要求4所述方法，其特征在于，所述第一基站具备至少4个天线，其中，所述4个天线用于发射所述第一通信制式的信号，其中至少2个天线用于发射第二通信制式的信号。
  6. 根据权利要求1-5中任一项所述方法，其特征在于，还包括：
    所述第一基站获取使用所述第一通信制式的第三基站在所述目标载波中的第二调度子载波的第三调制符号；
    所述第一基站根据所述码道信息和所述第一调制符号确定受控子载波的第二调制符号包括：
    所述第一基站根据所述第三调制符号、所述第一调制符号和所述码道信息确定所述第二调制符号，以使得所述第三调度子载波和所述受控子载波所共同承载的第二下行信号与所述OVSF码正交，所述受控子载波与所述第二调度子载波是不同的子载波。
  7. 根据权利要求1-6中任一项所述方法，其特征在于，所述使用正交频分复用的通信制式包括长期演进技术LTE制式和新无线NR制式。
  8. 根据权利要求1-7中任一项所述方法，其特征在于，所述使用扩频码或扰码的通信制式包括通用移动通信系统UMTS制式和码分多址接入CDMA2000制式。
  9. 根据权利要求1-8中任一项所述方法，其特征在于，所述第一基站使用根升余弦滤波器。
  10. 一种基站，其特征在于，包括：
    获取模块，用于获取第二基站的码道信息，所述码道信息包括所述第二基站使用的正交可变扩频因子OVSF码和所述第二基站所使用的扰码，所述第一基站为使用正交频分复用OFDM的第一通信制式的基站，所述第二基站为使用扩频码或扰码的第二通信制式的基站；
    确定模块，用于确定第一调度子载波的第一调制符号；
    计算模块，用于根据所述码道信息和所述第一调制符号计算受控子载波的第二调制符号，以使得所述第一调度子载波和所述受控子载波所共同承载的下行信号与所述OVSF码正交，所述受控子载波与所述第一调度子载波是不同的子载波；
    发送模块，用于使用所述第一调度子载波和所述受控子载波发送所述下行信号。
  11. 根据权利要求10述基站，其特征在于，
    所述计算模块，还用于确保所述第一下行信号的功率小于或等于预设功率。
  12. 根据权利要求10或11所述基站，其特征在于，若所述第一通信制式的基带采样频率小于所述第二通信制式的基带采样频率，所述基站还包括：
    采样模块，用于根据所述第二通信制式的基带采样频率对OFDM的有用符号进行过采样，使得所述第一通信制式的基带采样频率与所述第二通信制式的基带采样频率相等。
  13. 根据权利要求10-12中任一项所述基站，其特征在于，还包括：
    所述获取模块，还用于获取使用所述第一通信制式的第三基站在所述目标载波中的第二调度子载波的第三调制符号；
    所述计算模块，还用于根据所述第三调制符号、所述第一调制符号和所述码道信息计算所述第二调制符号，以使得所述第三调度子载波和所述受控子载波所共同承载的第二下行信号与所述OVSF码正交，所述受控子载波与所述第二调度子载波是不同的子载波。
  14. 一种基站，其特征在于，包括：
    收发器、处理器和存储器；
    所述收发器，用于获取第二基站的码道信息，所述码道信息包括所述第二基站使用的正交可变扩频因子OVSF码和所述第二基站所使用的扰码，所述第一基站为使用正交频分复用OFDM的第一通信制式的基站，所述第二基站为使用扩频码或扰码的第二通信制式的基站；
    所述处理器，用于确定第一调度子载波的第一调制符号，根据所述码道信息和所述第一调制符号确定受控子载波的第二调制符号，以使得所述第一调度子载波和所述受控子载波所共同承载的下行信号与所述OVSF码正交，所述受控子载波与所述第一调度子载波是不同的子载波；
    所述收发器，还用于使用所述第一调度子载波和所述受控子载波发送所述下行信号；
    所述存储器，用于存储程序、所述码道信息、所述第一调度子载波的第一调制符号和所述受控子载波的第二调制符号。
  15. 一种计算机可读存储介质，包括指令，当其在计算机上运行时，使得计算机执行如权利要求1-9所述的方法。
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CN101124749A (zh) * 2005-02-18 2008-02-13 Lg电子株式会社 用于抑制小区间干扰的无线多路接入系统
US20130258868A1 (en) * 2012-03-28 2013-10-03 Qualcomm Incorporated Method and Apparatus for Multicarrier Coverage Diversity
CN104798398A (zh) * 2012-11-26 2015-07-22 高通股份有限公司 利用小型小区间协作的小型小区上行链路干扰消除的系统和方法
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