WO2012174826A1

WO2012174826A1 - Data compression and decompression method, apparatus and system in distributed base station system

Info

Publication number: WO2012174826A1
Application number: PCT/CN2011/082836
Authority: WO
Inventors: 王润荣; 李彬; 许兵舰
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-06-24
Filing date: 2011-11-24
Publication date: 2012-12-27
Also published as: CN102843720B; CN102843720A

Abstract

Disclosed are a data compression and decompression method, apparatus and system in a distributed base station system. The compression method comprises the following steps: a remote radio unit (RRU) compresses the IQ data of each antenna in the unit of a predetermined number of chips according to the compression factor of the IQ data, and frames the compressed IQ data in the link frame format of a high speed interface protocol; and the RRU transmits the framed data via an optical fiber to a building baseband unit (BBU), wherein the framed data comprises the compression factor and a preamble sequence for locking the header of the predetermined number of chips. The present invention reduces equipment costs and improves the competitiveness of finished products.

Description

TECHNICAL FIELD The present invention relates to the field of communications, and in particular to a method, a device, and a system for compressing, decompressing, and compressing data in a distributed base station system. BACKGROUND OF THE INVENTION A distributed base station architecture has become a development trend of a wireless communication system. Based on the architecture, an indoor baseband unit (BBU) and a remote radio unit (RRU) are separated. Independent development, which reduces development costs and increases networking flexibility. Such a base station architecture has been recognized by more and more users, and applications are also increasing. In the distributed base station architecture, the BBU and the RRU are generally arranged in a remote manner by using optical fibers or other cables. One BBU can support multiple RRUs, and the distance can be up to several kilometers or even tens of kilometers, which requires wireless data transmission. The ability has been greatly improved. In the related art, the "BBU+RRU" multi-channel scheme can solve the problem of indoor coverage of large venues. Because there are usually floor slabs in the interior of large buildings, walls in rooms, and space between indoor and indoor users, the "BBU+RRU" multi-channel solution utilizes this feature for large stadiums with more than 100,000 square meters. The stand can be divided into several cells, and each cell is provided with several channels, and each channel corresponds to a panel antenna. The "BBU+RRU" scheme adopts the distribution mode of optical fiber transmission. The baseband BBU is placed in the equipment room, the RRU can be installed to the floor, the optical fiber is transmitted between the BBU and the RRU, and the RRU passes through the coaxial cable and the power splitter (coupler). Connected to the antenna, that is, the trunk uses fiber and the branch uses coaxial cable. Since the loss of the signal transmitted through the optical fiber is small, the overall feeder loss of the system is reduced, thereby reducing the dependence on the mains amplifier.

The communication between the BBU and the RRU is generally based on a high-speed interface protocol for data transmission. For example, in the Long Term Evolution (LTE), the Common Public Radio Interface (CPRI) is adopted. The high-speed interface protocol uses the Open Base Station Architecture Initiative (OBSAI) high-speed interface protocol in the World Interoperability for Microwave Access (WiMAX). Regardless of which interface protocol is used, the communication principle between the BBU and the RRU is the same, δΡ, according to the direction of data transmission, divided into downlink and uplink. The downlink refers to the optical fiber directly connected to the RRU from the BBU, and the baseband digital signal is transmitted between the BBU and the RRU, and several antennas are connected to the RRU, and the downlink data is transmitted through the antenna on the RRU; The link refers to the transmission of data from the RRU to the BBU. That is, after receiving the mobile phone user signal, the antenna on the RRU transmits the mobile phone user signal to the base station (BBU). When the uplink needs to support more antenna number configurations, it faces the problem of excessive data volume. In order to effectively reduce equipment costs and improve product competitiveness, data compression between BBU and RRU is very necessary. That is, the uplink IQ data is transmitted in the RRU (the signal is usually represented by a sine component and an cosine component, wherein the cosine component is called an in-phase component, that is, an inphase component, and the sinusoid component is called a quadrature component, that is, a Q component. (Orthogonal component), the inphase component and orthogonal component (IQ) data represents all the information of the signal), before the uplink IQ data is first compressed to reduce the amount of data transmitted in the uplink, Therefore, it is possible to transmit a larger amount of information at a lower optical port rate, reduce the cost of the optical module, and also improve the reliability of the hardware circuit design. However, the compression and decompression scheme of data transmission between the existing BBU and the RRU is relatively complicated to implement, and the development and manufacturing cost is relatively high. SUMMARY OF THE INVENTION A main object of the present invention is to provide a compression and decompression scheme for data in a distributed base station system, so as to at least solve the above-mentioned related art, a method for compressing and decompressing data transmitted between a BBU and an RRU is relatively complicated, and is developed and manufactured. The problem of high cost. In order to achieve the above object, according to an aspect of the present invention, a method of compressing data in a distributed base station system is provided. A method for compressing data in a distributed base station system according to the present invention includes the following steps: The RRU compresses IQ data of each antenna in units of a predetermined number of chips according to a compression factor of the IQ data, and compresses the compressed IQ. The data is framing according to the link frame format of the high-speed interface protocol; the RRU transmits the framing data to the BBU through the optical fiber, where the framing data includes a compression factor and a header for locking a predetermined number of chips. Lead sequence. Preferably, the compression factor includes an I channel compression factor and a Q channel compression factor, and the RRU compresses the IQ data of each antenna according to a compression factor of the IQ data in units of a predetermined number of chips, and the method further includes: The I channel compression factor and the Q channel compression factor of each antenna in a predetermined number of chips; the buffer space is allocated according to the bandwidth condition to store all samples of each antenna in a predetermined number of chips. Preferably, the RRU compresses the IQ data of each antenna by a compression factor of the IQ data in units of a predetermined number of chips. The RRU compresses all samples of each antenna in a predetermined number of chips, where The I channel data in the IQ data of each antenna is compressed according to the I channel compression factor, and the Q channel data in the IQ data of each antenna is compressed according to the Q channel compression factor. Preferably, the RRU calculates the I channel compression factor and the Q channel compression factor of each antenna in the predetermined number of chips, including: the RRU searches for the maximum number of absolute values in the I channel data of each antenna in the predetermined number of chips. If the sign bit of the number is m bits, the Bay ij l path compression factor is n, where m + n = 8, m and n take a natural number; RRU Q channel data of each antenna in a predetermined number of chips Find a number with the largest absolute value. If the sign bit of the number is i, the Q-channel compression factor is j, where i + j = 8, i and j take the natural number. Preferably, in the case that the high-speed interface protocol is the CPRI protocol, the chip is BF, and the compressed IQ data is framing according to the link frame format of the high-speed interface protocol, including: in each BF, different optical interfaces with different bandwidths At the rate, all the compressed data of the antennas are sequenced in the order of the antennas, wherein each antenna is placed in the order of the parameter information after the sample is placed. Preferably, the post-framing data further includes an uplink gain factor. In order to achieve the above object, according to another aspect of the present invention, a method of decompressing data in a distributed base station system is provided. A method for decompressing data in a distributed base station system according to the present invention includes the following steps: The BBU receives data from a RRU in a link frame format according to a high-speed interface protocol through an optical fiber, and according to a link frame of a high-speed interface protocol The format defragmented the data after the framing; the BBU obtains a preamble sequence for locking a header of a predetermined number of chips by blind detection, and parses the RRU according to the preamble sequence to each antenna in a predetermined number of chips. The compression factor when the IQ data is compressed; the BBU decompresses the deframed data according to the preamble sequence and the compression factor. Preferably, the BBU decompresses the de-framed data according to the preamble sequence and the compression factor. When the compression factor is p, the BBU adds q-bit symbol bit information before each de-framed data. The p-bit 0 is added to the last bit of the data after the frame, where p + q = 7, p and q take the natural number. In order to achieve the above object, according to still another aspect of the present invention, a method of processing data in a distributed base station system is also provided. A method for processing data in a distributed base station system according to the present invention includes the following steps: The RRU compresses IQ data of each antenna by a compression factor of the IQ data in units of a predetermined number of chips, and compresses the IQ after the compression. The data is framing according to the link frame format of the high-speed interface protocol, and the data after the framing is transmitted to the BBU through the optical fiber, where the data after the framing includes a compression factor and a preamble for locking the head of the predetermined number of chips. The BBU de-frames the data after the framing according to the link frame format of the high-speed interface protocol, obtains the preamble sequence by blind detection, and parses the compression factor according to the preamble sequence, and then de-frames according to the preamble sequence and the compression factor. The data is decompressed. Preferably, in the case where the high speed interface protocol is the CPRI protocol, the chip is BF; and in the case where the high speed interface protocol is the OBSAI protocol, the chip is a message. In order to achieve the above object, according to still another aspect of the present invention, an RRU is provided. The RRU according to the present invention includes: a compression module configured to compress IQ data of each antenna in accordance with a compression factor of IQ data in units of a predetermined number of chips; a framing module configured to follow the compressed IQ data The link frame format of the high speed interface protocol is framing; and the sending module is configured to transmit the framing data to the BBU through the optical fiber, where the framing data includes a compression factor and is used for locking a predetermined number of chips. The leading sequence of the head. In order to achieve the above object, according to still another aspect of the present invention, a BBU is provided. The BBU according to the present invention includes: a receiving module configured to receive, by using an optical fiber, data from a RRU in a link frame format according to a high speed interface protocol; a frame splitting module, configured to follow a link frame format of a high speed interface protocol The framing data is deframed; the obtaining module is configured to obtain a preamble sequence for locking a header of a predetermined number of chips by blind detection, and parse out the RRU according to the preamble sequence to each of the predetermined number of chips. a compression factor when the IQ data of the antenna is compressed; and a decompression module configured to decompress the deframed data according to the preamble sequence and the compression factor. In order to achieve the above object, according to another aspect of the present invention, a processing system for data in a distributed base station system is also provided. A data processing system in a distributed base station system according to the present invention includes the above-described RRU and the above-described BBU. Through the invention, combined with the radio frame format in the communication system, the IQ data compressed by the compression factor is framing according to the link frame format of the high-speed interface protocol, and the transmission between the BBU and the RRU in the related art is solved. The data compression and decompression methods are more complicated to implement, and the development and manufacturing cost are high, which reduces the equipment cost and improves the product competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, In the drawings: FIG. 1 is a flowchart of a method for compressing data in a distributed base station system according to an embodiment of the present invention; FIG. 2 is a flowchart of a method for decompressing data in a distributed base station system according to an embodiment of the present invention; 3 is a flowchart of a method for processing data in a distributed base station system according to an embodiment of the present invention; FIG. 4 is a structural block diagram of an RRU according to an embodiment of the present invention; and FIG. 5 is a structural block diagram of a BBU according to an embodiment of the present invention; 6 is a structural block diagram of a data processing system in a distributed base station system according to an embodiment of the present invention; FIG. 7 is a schematic diagram of uplink processing between a BBU and an RRU according to Embodiment 1 of the present invention; FIG. FIG. 9 is a schematic diagram of a frame structure of a CPRI basic frame at a 3.072 G optical port rate according to Embodiment 2 of the present invention; FIG. 10 is a RRU side according to Embodiment 2 of the present invention; FIG. 11 is a schematic diagram of a transmission frame format of a compression factor and an uplink gain according to Embodiment 2 of the present invention; FIG. 12 is a P of different bandwidths according to Embodiment 2 of the present invention; FIG. 13 is a schematic diagram of a CPRI link mapping pattern of a 20M cell at a 3.072G optical port rate according to Embodiment 2 of the present invention; FIG. 14 is a schematic diagram of decompression of a BBU side according to Embodiment 2 of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. According to an embodiment of the present invention, a method for compressing data in a distributed base station system is provided. 1 is a flowchart of a method for compressing data in a distributed base station system according to an embodiment of the present invention. As shown in FIG. 1, the method includes the following steps: Step S102: The RRU will each perform in units of a predetermined number of chips. The IQ data of the antenna is compressed according to the compression factor of the IQ data, and the compressed IQ data is framing according to the link frame format of the high-speed interface protocol. In step S104, the RRU transmits the data after the framing to the BBU through the optical fiber. The framing data includes the foregoing compression factor and a preamble sequence for locking a header of a predetermined number of chips (preambled is combined with a radio frame format in a communication system by using the above steps, and the compression factor is compressed. The IQ data is framing according to the link frame format of the high-speed interface protocol, which solves the problem that the compression and decompression methods of the data transmission between the BBU and the RRU in the related art are complicated, the development and manufacturing cost are high, and the equipment cost is reduced. , improving product competitiveness. Preferably, the compression factor includes an I channel compression factor and a Q channel compression factor, in step S102 Before the RRU compresses the IQ data of each antenna in units of a predetermined number of chips according to the compression factor of the IQ data, the RRU can calculate the I channel compression factor and the Q channel compression factor of each antenna in the predetermined number of chips. Allocating all the samples of each antenna in a predetermined number of chips according to the bandwidth condition. This method can improve the adaptability and flexibility of the system. Preferably, the RRU calculates the I of each antenna in a predetermined number of chips. The path compression factor and the Q channel compression factor include: the RRU searches for the largest number of absolute values in the I path data of each antenna in the predetermined number of chips, and if the sign bit of the number is m bits, the ij l path compression The factor is n, where m + n = 8, m and n take a natural number; the RRU finds a maximum number of absolute values in the Q channel data of each antenna in a predetermined number of chips, if the sign bit of the number is i bit, then the Q channel compression factor is j, where i + j = 8, i and j take the natural number. This method has the advantage of improving the accuracy and effectiveness of the system. Preferably, in step S102, the RRU is in a predetermined number. Chip Compressing the IQ data of each antenna according to the compression factor of the IQ data includes: RRU compresses all samples of each antenna in a predetermined number of chips, wherein I in the IQ data of each antenna The road data is compressed according to the I channel compression factor, and the Q channel data in the IQ data of each antenna is compressed according to the Q channel compression factor. The method is simple, practical, and operability. Preferably, the high speed interface protocol is CPRI protocol. In the case that the chip is a basic frame (abbreviated as BF), in step S102, the compressed IQ data is in accordance with the link frame format of the high speed interface protocol. The row group frame includes: In each BF, the data compressed by all the antennas at different optical port rates of different bandwidths are coded in the order of the antennas, wherein each antenna is placed in the order of the parameter information after the sample is placed. . Preferably, the post-framing data further includes an uplink gain factor. This method can improve the processing power of the system. Corresponding to the method for compressing data in the distributed base station system, the embodiment of the present invention further provides a method for decompressing data in a distributed base station system. 2 is a flowchart of a method for decompressing data in a distributed base station system according to an embodiment of the present invention. As shown in FIG. 2, the method includes the following steps: Step S202: A BBU receives a link according to a high-speed interface protocol from an RRU through an optical fiber. Frame format framing data, and framing the framing data according to the link frame format of the high speed interface protocol; Step S204, the BBU obtains a preamble sequence for locking a header of a predetermined number of chips by blind detection, And parsing, according to the preamble sequence, a compression factor when the RRU compresses the IQ data of each antenna by a predetermined number of chips; and in step S206, the BBU decompresses the framed data according to the preamble sequence and the compression factor. Through the above steps, the method of combining with the radio frame format in the communication system is adopted to solve the problem that the compression and decompression methods of the data transmitted between the BBU and the RRU in the related art are relatively complicated, and the development and manufacturing cost are high, and the device is lowered. Cost, improve product competitiveness. For example, in step S204, the BBU first acquires the preamble sequence by blind detection, and then locks the header of the predetermined number of chips according to the preamble sequence, and then parses the I/Q compression factor according to the header of the chip. Preferably, in step S206, when the compression factor is p, the BBU adds q-bit symbol bit information before each de-framed data, and adds p-bit 0 to the last data bit after each de-frame. p + q = 7, p and q take natural numbers. According to an implementation of the present invention, a method of processing data in a distributed base station system is also provided. FIG. 3 is a flowchart of a method for processing data in a distributed base station system according to an embodiment of the present invention. As shown in FIG. 3, the method includes the following steps: Step S302: The RRU sends each antenna in units of a predetermined number of chips. The IQ data is compressed according to the compression factor of the IQ data, and the compressed IQ data is framing according to the link frame format of the high speed interface protocol; Step S304, the RRU transmits the framing data to the BBU through the optical fiber, where the framing data includes a compression factor and a preamble sequence for locking a header of the predetermined number of chips. Step S306, the BBU follows the high-speed interface protocol. The link frame format de-frames the data after the framing, obtains the preamble sequence by blind detection, and parses the compression factor according to the preamble sequence; in step S308, the BBU decompresses according to the preamble sequence and the compression factor pair. Through the above steps, the method of combining with the radio frame format in the communication system is adopted to solve the problem that the compression and decompression methods of the data transmitted between the BBU and the RRU in the related art are relatively complicated, and the development and manufacturing cost are high, and the device is lowered. Cost, improve product competitiveness. Preferably, in the case that the high speed interface protocol is a CPRI protocol, the chip is a basic frame (BF); in the case where the high speed interface protocol is an open base station architecture OBSAI protocol, the chip is a message (messaged corresponds to the above distributed base station system) The embodiment of the present invention further provides an RRU. FIG. 4 is a structural block diagram of an RRU according to an embodiment of the present invention. As shown in FIG. 4, the RRU 40 includes: a compression module 42 configured to be in a predetermined number. The chip data is compressed in units of IQ data of each antenna according to the compression factor of the IQ data; the framing module 44 is coupled to the compression module 42 and configured to compress the IQ data according to the link frame format of the high speed interface protocol. The framing is performed; and the transmitting module 46 is coupled to the framing module 44, and configured to transmit the framing data to the BBU through the optical fiber, where the framing data includes the foregoing compression factor and is used for locking a predetermined number of codes. The preamble sequence of the slice header. In combination with the radio frame format in the communication system, the framing module 44 compresses the IQ data compressed by the compression module 42 according to the high speed interface. The proposed link frame format is framing, which solves the problem that the compression and decompression methods of data transmission between the BBU and the RRU in the related art are complicated, and the development and manufacturing cost are high, the equipment cost is reduced, and the product competitiveness is improved. A BBU is provided in the embodiment of the present invention, and the BBU 50 includes: The module 52 is configured to receive, by the optical fiber, the data after the frame frame format of the link frame format according to the high speed interface protocol from the RRU; the frame splitting module 54 is coupled to the receiving module 52, and is set to the link frame format according to the high speed interface protocol. The post-frame data is deframed; the obtaining module 56 is coupled to the deframing module 54 and configured to acquire a preamble sequence for locking a header of a predetermined number of chips by blind detection, and parse the RRU according to the preamble sequence by a predetermined number. a chip is a compression factor when the IQ data of each antenna is compressed; and a decompression module 58 is coupled to the acquisition module 56, and is set to The deframed data is decompressed according to the preamble sequence and the compression factor. Corresponding to the processing method of the data in the distributed base station system, the embodiment of the present invention further provides a data processing system in the distributed base station system. 6 is a structural block diagram of a data processing system in a distributed base station system according to an embodiment of the present invention. As shown in FIG. 6, the system includes the above-described RRU 40 and the above-described BBU 50. The implementation process of the above embodiment will be described in detail below in conjunction with the preferred embodiments and the accompanying drawings. Embodiment 1 The present invention provides a method and apparatus for data compression and decompression between a distributed base station system BBU and an RRU, which solves the problem of excessive uplink data, thereby reducing equipment cost and improving product competition. force. It should be noted that the LTE system is only used as an example, and is not limited to the LTE system, but also applicable to communication systems of various standards such as WiMAX. Other systems are similar to the principles and the same applies. FIG. 7 is a schematic diagram of uplink processing between a BBU and an RRU according to the first embodiment of the present invention. As shown in FIG. 7, the device compression part of the embodiment is implemented on the RRU side, and the decompression part is implemented on the BBU side. For example, in the uplink processing, the RRU receiving antenna receives the user signal, performs A/D conversion (ie, analog-to-digital conversion) through the intermediate frequency module, and then compresses the data through the compression module (for example, compressing data from 16 bits in LTE to 9bit), then, carried on the high-speed protocol interface for transmission, and connected to the BBU side through the optical fiber through the optical module, the BBU performs inverse processing, decompresses to obtain the baseband signal, and then performs baseband subsequent processing. In the implementation process, the data interaction between the BBU and the RRU is based on a high-speed interface protocol. Different high-speed interface protocols are adopted in different standards. CPRI high-speed interface protocol is adopted in LTE, and OB S AI high-speed interface protocol is adopted in WiMAX. It should be noted that the wireless communication system has the concept of a wireless frame format. Similarly, each high-speed interface protocol has its own minimum transmission unit. The minimum transmission unit in CPRI is a basic frame, and the transmission convention format of each basic frame. That is, the basic frame format. Similarly, the smallest transmission unit in OBSAI is Message, which also has its agreed format. For example, in the LTE system, the CPRI protocol is used. If the length of a basic frame (BF) is lTC=l/3.84MHz=260.416667ns, a basic frame contains 16 words (W=0.. ..15). The first word W=0 of the basic frame is a control word for controlling and managing the transmission of the plane and the synchronization plane information, and the remaining 15 words (W=l~15) are data words for the user. Plane data (ie, transmission of IQ data), the length T of each word depends on the linear rate of the CPRI. In the implementation process, the number of samples per antenna in each BF is different under different bandwidth configurations of the LTE system. For example, at 20M, there are 8 samples per antenna in each BF, and at 10M, there are 4 samples per antenna in each BF. At 5M, each BF has 2 samples per antenna. FIG. 8 is a schematic diagram of various bandwidth HALF_AXC allocations according to the first embodiment of the present invention. As shown in FIG. 8, the compressed I/Q channel data is carried on an antenna carrier (Antenna Carrier, AXC) container of the CPRI link. on. One AXC container is 30 bits, and half AXC or one HALF_AXC container is 15 bits. In order to facilitate the simulation with other products, when the antenna data is allocated, it is allocated in units of one HALF_AXC container. When less than one HALF_AXC is used, the reserved bits are used. In this embodiment, LTE is taken as an example. The RRU side compresses the IQ data of each antenna by 32 BFs (the value of 32 is not absolute, depending on the transmission capability and resources), and the I/Q channel data is from the original. The 16-bit compression is 9 bits (the number of bits after compression is the result of the balance between the simulation evaluation performance and the actual optical module cost, and the 9-bit number is not absolute). The I/Q path compression factor and the (preamble) parameters used to lock the 32 BF headers are added as the associated parameters to the middle of the IQ data for transmission. The BBU side can obtain 32 BF headers based on the preamble blind detection. Then, the opposite operation to the RRU side is performed, that is, the I/Q data is decompressed from 9 bits to 16 bits. It can be seen that the data transmission method of compressing and decompressing between the baseband unit and the radio unit is completed by using the CPRI interface, which can solve the problem that the amount of uplink data is too large in the bandwidth and the higher configuration of the antenna when the CPRI protocol standard implements the baseband radio interface. In addition, the compression decompression device proposed in this embodiment also clarifies the implementation position and specific operation of the method. Embodiment 2 FIG. 9 is a schematic diagram of a frame structure of a CPRI basic frame (BF) (ie, a chip chip) at a 3.072 G optical port rate according to Embodiment 2 of the present invention. As shown in FIG. 9, the RRU and the BBU are used. For example, the data compression method of the RRU side provided by this embodiment is described in detail. FIG. 10 is a schematic diagram of compression on the RRU side according to Embodiment 2 of the present invention. As shown in FIG. 10, the compression process includes the following steps: Step 1, RRU side compression processing. Perform IQ data compression on each antenna in units of 32 basic frames (BF) on the RRU side. To facilitate the corresponding decompression, add the I or Q compression factor and the uplink gain factor to the compressed data. Transfer together. 11 is a schematic diagram of a transmission frame format of a compression factor and an uplink gain according to Embodiment 2 of the present invention. As shown in FIG. 11, a preamble is set to understand a header of a compression-locked 32 basic frame (BF). That is 12'bl ll l_l ll l_l lll. This step is further divided into three sub-steps:

(1) Calculate the respective compression factor scale values (i.e., scaling values) for each of the antennas I and Q of each of the 32 basic frames (BF). The I road scale value method is to find in each antenna I channel data of 32 basic frames (BF). To a value with the largest absolute value, if the sign bit of the number has 1 bit, then the scale value is equal to 7; if the sign bit of the number has 2 bits, then the scale value is equal to 6. By analogy, the scale value is from 0 to 7. Similarly, the Q-scale value calculation method is the same as the I-way.

(2) All the samples of each antenna of 32 basic frames (BF) are buffered, and the development of the buffer space is opened according to the maximum bandwidth value of 20M, so that resource sharing can be achieved. FIG. 12 is a schematic diagram of buffering of PING PONG at different bandwidths according to Embodiment 2 of the present invention. As shown in FIG. 12, in order to buffer data while the compressed data is composed of CPRI frames for transmission, it is necessary to open up The space is multiplied by 2 for PING PONG operations (ie, a processing technique commonly used for data flow control, the input data stream and the output data stream are continuously pipelined, and the input and output do not conflict with each other. ). (3) Compress all samples of each antenna for 32 basic frames (BF). The I path and the Q path are respectively performed. Taking the I path as an example, the I path compression factor scale value is obtained in step one. When the scale value is equal to 7, the lowest 7-bit data is cut off during compression, and the high 9-bit data is retained; When the scale value is equal to 6, the lowest 6-bit data is truncated during compression, and the lbit sign bit is removed. The remaining 9-bit data after the end of the tail is the compressed data. The scale value is similar for other values. Q-channel compression is also the same as I-way. Step 2: RPR side CPRI framing. The CPRI framing is performed in accordance with the code placement table of each antenna compressed data in each basic frame (BF). 13 is a schematic diagram of a CPRI link mapping pattern of a 20M cell at a 3.072 G optical port rate according to Embodiment 2 of the present invention. As shown in FIG. 13, a mapping pattern of a 20M cell at a 3.072 G optical port rate is used as an example. The basic frame (BF) has 16 Words, each of which has 5 Bytes. There are 8 samples per antenna in each basic frame (BF) at 20M bandwidth. When framing, the compressed IQ data is coded in the order of antenna 0 -> antenna 1 - antenna 2 -> antenna 3, and I and Q are interleaved. In particular, the I/Q compression factor, uplink gain, and preamble of each antenna are immediately after each antenna, ie, a0, al, a2, a3. 32 bits are transmitted in 32 BFs. For example, in each basic frame, data compressed by all antennas at different optical port rates of different bandwidths is coded in order of antennas (one antenna data code is discharged and another antenna data is placed), and each antenna is coded according to the code. The order of the parameter information (for obtaining the parameter information of the I/Q compression factor, etc.) after the sample point (the compressed IQ data) is performed. In particular, a reserved bit r is provided between the antenna and the antenna to satisfy antenna data distribution in units of one HALF_AXC container. As shown in Figure 13, at the 20M bandwidth, there is a total of 150 bits to the left of the first black body vertical line, that is, 10 HALF_AXC. Step 3: Phase reversal of CPRI framing on the BBU side, CPRI on the RRU side. 14 is a schematic diagram of decompression on the BBU side according to Embodiment 2 of the present invention. As shown in FIG. 14, the frame is removed according to the code placement table of the CPRI link frame at different optical port rates, and each BF is connected to each antenna. The IQ data of the samples are deinterlaced. At the same time, the preamble and the I/Q data compression factor are parsed. Step 4: 32 BF heads are blindly detected on the BBU side. The preamble is blindly detected to lock the heads of 32 BFs, which is the key to decompression processing. The 12-bit sequence in the 32-bit parameter information obtained after the CPRI is de-framed is judged. Once the preamble, 12'bllll_llll_l lll, appears, it is considered to be the header of 32 basic frames (BF). There are two cases when performing blind detection:

(1) The fiber is properly plugged in and the uplink is normal. At this time, blind detection is performed according to the normal procedure, and 32 BF heads can be obtained for subsequent PING PONG operations.

(2) The fiber is broken and the uplink is abnormal. At this time, the BBU side does not receive the preamble information. To prevent subsequent operations from being affected, and avoid receiving dirty data from the PING PONG RAM on the uplink, the local watchdog circuit can obtain 32 BF headers. Step 5: The BBU side decompression process, that is, the inverse process of the RRU side compression process. Decompress all samples of each antenna in units of 32 basic frames (BF) on the BBU side. This step is further divided into three sub-steps:

(1) Obtain the I/Q path data scale value. Once the 32 basic frame (BF) headers are locked, the I/Q compression factor can be obtained in the frame format shown in Figure 10. A shift operation can be taken when saving 32-bit parameter information.

(2) Deinterleave all samples of each antenna in 32 basic frames (BF) and cache them. For the same reason, the development of the cache space is the same as that of the compression side, and the PING PONG operation should also be considered when opening up.

(3) Decompression processing, which restores 9-bit compressed data to 16 bits according to the obtained I/Q path compression factor. When the compression factor is equal to 0, when decompressing, 7-bit symbol bit information can be added before the 9-bit compressed data; when the compression factor is equal to 1, when decompressing, 6-bit symbol bit information is added before the 9-bit compressed data, and at the same time Add 1 bit 0; when the compression factor is equal to other values, the operation is the same. In summary, the embodiments of the present invention provide a method and device for data compression and decompression of a distributed base station system, and in combination with a radio frame format, in the case of controlling device cost and excessive data amount, in the BBU and the RRU Data compression and decompression are performed. Since the concept of the radio frame format exists in the communication system, it is not limited by the specific communication system, and is suitable for communication between BBUs and RRUs of various standards. For example, LTE, WiMAX, etc. It will be apparent to those skilled in the art that the various modules or steps of the present invention described above can be implemented by a general-purpose computing device that can be centralized on a single computing device or distributed across multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device so that they may be stored in the storage device by the computing device, or they may be separately fabricated into individual integrated circuit modules, or Multiple of these modules or steps are fabricated as a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software. The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim

A method for compressing data in a distributed base station system, comprising the steps of:

The remote radio unit RRU compresses the IQ data of each antenna by a compression factor of the IQ data in units of a predetermined number of chips, and compresses the IQ data according to a link frame format of a high speed interface protocol. Grouping

The RRU transmits the framing data to the indoor baseband processing unit BBU through the optical fiber, where the framing data includes the compression factor and a preamble sequence for locking the header of the predetermined number of chips. .

2. The method according to claim 1, wherein the compression factor comprises an I channel compression factor and a Q channel compression factor, and the RRU uses the IQ data of each antenna in units of the predetermined number of the chips. Before compressing according to the compression factor of the IQ data, the method further includes:

The RRU calculates the I-channel compression factor and the Q-channel compression factor for each of the predetermined number of the chips;

The cache space is allocated according to the bandwidth condition to store all of the predetermined number of samples of each of the chips.

3. The method according to claim 2, wherein the RRU compresses IQ data of each antenna according to a compression factor of the IQ data in units of the predetermined number of the chips, including:

The RRU compresses all samples of each of the predetermined number of the chips, wherein the I channel data in the IQ data of each antenna is compressed according to the I channel compression factor. The Q channel data in the IQ data of each antenna is compressed according to the Q channel compression factor.

The method according to claim 2, wherein the RRU calculates the I-channel compression factor and the Q-channel compression factor of each of the predetermined number of the chips, including:

The RRU searches for one of the I-channel data of each of the predetermined number of the chips to obtain a maximum absolute value, and if the sign bit of the number is m bits, the I-channel compression factor is n. , where m + n = 8, m and P n take a natural number;

The RRU searches for a maximum number of absolute values in the Q channel data of each of the predetermined number of the chips, and if the sign bit of the number is i bits, the Q channel compression factor is j , where i + j = 8, i and j take the natural number.

5. The method according to claim 1, wherein, in a case where the high speed interface protocol is a general public radio interface (CPRI) protocol, the chip is a basic frame BF, and the compressed IQ data is as described. The frame frame format of the high-speed interface protocol for framing includes:

In each BF, the data compressed by all the antennas at different optical port rates of different bandwidths are sequenced in the order of the antennas, wherein each antenna is coded in the order of the parameter information after the sample is placed.

The method according to any one of claims 1 to 5, wherein the post-framing data further comprises an uplink gain factor.

7. A method for decompressing data in a distributed base station system, comprising the steps of:

The indoor baseband processing unit BBU receives the data after the framing of the link frame format according to the high-speed interface protocol from the remote radio unit RRU through the optical fiber, and compares the data after the framing according to the link frame format of the high-speed interface protocol. Defragmenting;

The BBU obtains a preamble sequence for locking a header of the predetermined number of chips by blind detection, and parses out the RRU according to the preamble sequence to perform IQ data of each antenna in units of a predetermined number of chips. Compression factor at compression;

The BBU decompresses the framed data according to the preamble sequence and the compression factor.

The method according to claim 7, wherein the BBU decompresses the framed data according to the preamble sequence and the compression factor, including:

When the compression factor is p, the BBU adds q-bit symbol bit information before each of the de-framed data, and adds p-bit 0 to the last data after the de-framed data, where p + q = 7, p and q take natural numbers.

9. A method of processing data in a distributed base station system, comprising the steps of:

The remote radio unit RRU compresses the IQ data of each antenna by a compression factor of the IQ data in units of a predetermined number of chips, and compresses the IQ data according to a link frame format of a high speed interface protocol. The framing, the framing data is further transmitted to the indoor baseband processing unit BBU through the optical fiber, where the framing data includes the compression factor and a preamble sequence for locking the header of the predetermined number of chips ;

Decoding the framed data according to the link frame format of the high speed interface protocol, obtaining the preamble sequence by blind detection, and parsing the compression factor according to the preamble sequence, and then The preamble sequence and the compression factor decompress the deframed data.

10. The method according to claim 9, wherein, in the case that the high speed interface protocol is a general public radio interface CPRI protocol, the chip is a basic frame BF; and the high speed interface protocol is an open base station architecture OBSAI In the case of a protocol, the chip is a message.

11. A remote radio unit RRU, comprising:

a compression module, configured to compress IQ data of each antenna according to a compression factor of the IQ data in units of a predetermined number of chips; a framing module configured to compress the IQ data according to a high speed interface protocol The link frame format is framing; and the sending module is configured to transmit the framing data to the BBU through the optical fiber, where the framing data includes the compression factor and is used for locking the predetermined number The leading sequence of the head of the chip.

12. An indoor baseband processing unit BBU, comprising:

a receiving module, configured to receive, by using an optical fiber, data from a remote radio unit RRU in a link frame format framing according to a high speed interface protocol; and a detaching frame, configured to follow the link frame format of the high speed interface protocol The framing data is deframed; the obtaining module is configured to obtain a preamble sequence for locking the header of the predetermined number of chips by blind detection, and parse the RRU according to the preamble sequence by a predetermined number of codes a compression factor when compressing IQ data of each antenna in units of slices; and a decompression module configured to decompress the deframed data according to the preamble sequence and the compression factor. A data processing system in a distributed base station system, comprising the RRU of claim 11 and the BBU of claim 12.