CN101436896A - IQ data transmission method of radio frequency zooming unit - Google Patents

Abstract

The invention discloses a method for transmitting IQ data of radio-frequency remote units, which achieves cascade transmission for the IQ data. The method cascades the radio-frequency remote units to a baseband pool unit in a chain mode, a carrier number occupied by the IQ data of each radio-frequency remote unit is distributed by the baseband pool unit, and the IQ data are organized and transmitted according to a frame format. Trough cascade of the radio-frequency remote units (RRU), the method increases coverage area of a base station, improves flexibility of network arrangement, and reduces selection difficulty of a machine room greatly.

Description

A kind of IQ data transmission method of Remote Radio Unit

Technical field

The present invention relates to the 3G communication technology, specifically, relate to a kind of IQ data transmission method of Remote Radio Unit.

Background technology

Whole TD-SCDMA system is made up of base station (Node B), radio network controller (RNC), core network system (CN) and travelling carriage (UE) four parts.Along with the development of wireless radio-frequency, the developing trend of base station is zoomed out middle radio frequency part by optical fiber in base band signal process is separated with middle radio frequency processing.In the base station (Node B), main control part and Base-Band Processing partly are referred to as BBU (Base Band Unit baseband pool unit), and Digital IF Processing and radio frequency part are referred to as RRU (Radio Remote Unit Remote Radio Unit).

Traditional way is the light mouth control of a BBU and manages a RRU at present, and the limitation of this mode is a lot, is unfavorable for flexible networking on the one hand, and the increase in demand to the place has also increased cost to operator in addition.

Summary of the invention

Technical problem to be solved by this invention is the IQ data transmission method that is to provide Remote Radio Unit among the NODE-B in a kind of TD-SCDMA and WCDMA field, realizes a kind of cascade transmission to the IQ data.

In order to solve the problems of the technologies described above, the invention provides a kind of IQ data transmission method of Remote Radio Unit, Remote Radio Unit cascaded up in the chain mode be connected to baseband pool unit, the shared carrier number of IQ data of Remote Radio Unit at different levels is distributed by baseband pool unit, and the IQ data are organized according to frame format and transmitted.

In the said method, described Remote Radio Unit can be realized by extensive Field Programmable Gate Array.

In the said method, can be combined into a complete frame to the data of every grade of Remote Radio Unit according to frame format.

In the said method, the carrier number that every grade of Remote Radio Unit takies can not repeat.

In the said method, in the IQ data from the baseband pool unit to the Remote Radio Unit or the down direction from Remote Radio Unit at the corresponding levels to back level Remote Radio Unit: Remote Radio Unit at the corresponding levels can obtain the IQ data according to carrier number, local clock through phase-locked loop with the road clock synchronization after, the IQ data are converted to analog if signal launch, simultaneously the IQ data forwarding is arrived back level Remote Radio Unit;

In the IQ data from the Remote Radio Unit to the baseband pool unit or the up direction from Remote Radio Unit at the corresponding levels to the prime Remote Radio Unit: the IQ data of Remote Radio Unit at the corresponding levels can be converted to digital medium-frequency signal, local clock through phase-locked loop with the road clock synchronization after, the carrier number of occupying according to the corresponding levels and the position of the up frame head of Remote Radio Unit at the corresponding levels, the IQ data are inserted into corresponding carrier wave allocation position launch, simultaneously with the IQ data forwarding to the prime Remote Radio Unit.

Further, the IQ data can be carried out buffer memory by pushup storage, to eliminate the clock jitter that phase-locked loop causes.

And, in the described up direction, can be by the control of the forwarding enable signal that number produces by the local carrier of baseband pool unit configuration, the IQ data that the IQ data and the back level Remote Radio Unit of Remote Radio Unit at the corresponding levels sends over are transmitted respectively.

Compared with prior art, the inventive method constitutes the chain type transmission by some grades of RRU are cascaded up in the mode of chain with BBU, finishes the function of Node B.Zoom out and the cascade of RRU by radio frequency, increased the area coverage of base station, improve the flexibility ratio of networking, greatly reduce the selection difficulty of machine room.

Description of drawings

Fig. 1 is the cascade model schematic diagram.

Fig. 2 transmits the data flow direction schematic diagram for cascade.

Fig. 3 is for back level IQ metadata cache RAM write address and write the sequential chart that enables.

The sequential chart that Fig. 4 reads the address and reads to enable for back level IQ metadata cache RAM.

Embodiment

Below describe conjunction with figs. and embodiment in detail embodiments of the present invention, how the application technology means solve technical problem to the present invention whereby, and the implementation procedure of reaching technique effect can fully understand and implements according to this.

The present invention relates to the method for radio frequency remote unit RRU IQ data cascade transmission among the NODE-B in TD-SCDMA and WCDMA field.A RRU is controlled and managed to a BBU light mouth in the prior art, the limitation of this mode is a lot, therefore thought of the present invention is to introduce concatenation technology, and the light mouth of such BBU just may be managed and control a plurality of by chain mode cascade RRU together.Zoom out and the cascade of RRU by radio frequency, just can increase the area coverage of base station, improve the flexibility ratio of networking, reduce the city machine room of operator greatly and select difficulty, reduce engineering construction and maintenance difficulties simultaneously.

What RRU the cascade of the IQ data of RRU of the present invention cascades up in the mode of chain, be connected with BBU with optical fiber, realizes the transmitting-receiving of IQ data, and BBU and RRU at different levels are linked together easily and reliably, finishes the function of Node B.Connect topological diagram referring to Fig. 1, suppose 3 grades of cascades,RRU0 100 is connected on theBBU 10, and RRU1 is associated on theRRU0 100 for 110 grades, and RRU2 is associated on theRRU1 110 for 120 grades.Cascade is transmitted and to be comprised both direction, and is promptly descending and up, descending be meant data flow from BBU to RRU or from RRU at the corresponding levels to back level RRU,RRU0 100 as shown in FIG. arrives RRU1 110; The up data flow that is meant from RRU to BBU or RRU from the RRU of back level to prime, RRU1 110 toRRU0 100 as shown in FIG..

Data betweenBBU 10 and the RRU make up according to certain frame format, to finish the cascade forwarding capability, just must be combined into a complete frame to the data of every grade of RRU frame format according to the rules.In the middle of embodiments of the invention, transmission frame-form between RRU and theBBU 10 is a unit with 10 milliseconds, 10 milliseconds of frames are divided into 100 super bags (super-group), and each super bag (super-group) comprises 8 bags, and each bag comprises 16 son bags (sub-group) again.The smallest vessel of IQ data is exactly a sub-group, the IQ data of 24 carrier waves have been carried among each sub-group, the position of the numbering of each carrier wave in sub-group fixed, concerning each grade RRU, the carrier number that takies (numbering of carrier wave) is distributed by signaling byBBU 10, and the carrier number that the RRU of all cascades takies can not repeat.Concerning RRU, the IQ data are time-sharing multiplex in a sub-group so, so the IQ forwarding of data enables relevant with the carrier wave configuration.

As shown in Figure 2, two RRU are embodiment with cascade, when uplink and downlink receive direction of the present invention is described, and the transmission method of IQ data.RRU in the method for the invention realizes with extensive Field Programmable Gate Array (FPGA).Below respectively descending receive direction and up receive direction are described.

In the descending receive direction, illustrate that at first RRU at the corresponding levels is in the processing that receives IQ data clock territory.Since receive the clock of data and be from the light mouth recover with the road clock, and RRU at the corresponding levels extracts and the clock of forwarding IQ data is that the local crystal vibration produces, local clock is through phase-locked loop and with the road clock synchronization, in order to eliminate the clock jitter that phase-locked loop causes,, the data that send over from BBU or prime RRU carry out caching process so need passing through FIFO (pushup storage).

The extraction and the forwarding of RRU at the corresponding levels IQ data in descending receive direction are described then.After the FIFO processing, RRU at the corresponding levels is according to the carrier wave sequence number of BBU configuration, obtain the IQ data from the correspondence position of each sub-group, the processing in advanced row clock territory, export to DUC+D/A (Digital Up Convert chip and analog-digital chip), become analog if signal and deliver to radio-frequency module, launch through antenna at last; Simultaneously, all IQ data all are forwarded to back level RRU.

In the up receive direction, the insertion operation of RRU at the corresponding levels to the IQ data is described at first.After the IQ data of RRU at the corresponding levels are received by the radio-frequency channel, be converted to digital signal, pass through DDC (Digital Down Convert chip) again and convert digital medium-frequency signal to and be sent among the FPGA through A/D (mould/number conversion chip).Through the conversion of clock zone, the carrier information that occupies according to the corresponding levels of BBU configuration according to the position of the up frame head of RRU at the corresponding levels, is inserted into corresponding carrier wave allocation position to the IQ data then in FPGA.

Illustrate then RRU at the corresponding levels in up receive direction to the IQ data that level RRU in back sends extract separately, storage and framing transmit, this process is divided into following several steps again:

(1) conversion in back level input IQ data clock territory

Equally also there is the problem of clock zone in the IQ data that back grade RRU comes, thus after entering FPGA, also want carry out caching process with FIFO earlier, and then carry out the framing transmission with local IQ data.The IQ data are carried out time-sharing multiplex in a sub-group, because there are certain time delay in the reception frame head and the transmission frame head at the corresponding levels of coming from the back level, and this time delay integral multiple of sub-group not necessarily directly insert among each sub-group so can not directly receive the IQ data that come to the back level.And will be sending out on the correct framing of IQ data of the IQ data of back level and the corresponding levels, must the IQ data that the back level is come be properly inserted in other carrier position of sub-group, therefore back grade IQ data of coming are carried out buffer memory with a dual port RAM, and the size of buffer memory is the carrier data of 2 sub-group.Can carry out buffer memory with the data that the RAM resource of minimum is come to the back level like this.

(2) read/write address of back grade IQ metadata cache dual port RAM and the processing that read-write enables

Write address begins to calculate according to the frame head of back level input, begins to produce the address counting from sub-group when initial, and full two sub-group are just passable for meter.As shown in Figure 3, write address begins to count from receiving frame head, and the IQ data of 24 carrier waves are arranged among each sub-group, so produce 48 write addresses (among the figure as AD0～AD47), two sub-group, write address be altogether 96 (shown in the figure as AD0～AD95).When producing write address, enable to be set to high level writing.

The position of the initial sub-group of back level input IQ data hints obliquely at that correspondence also has a sub-group numbering in the transmit frame of the corresponding levels, is sign with this sub-group, delay a sub-group as read the address initial calculate to produce read the address.As shown in Figure 4, also be 48 addresses, a corresponding sub-group (the corresponding sub-group (n) of AD0～AD47, the corresponding sub-group (n+1) of AD48～AD95) as shown in the figure.

It is different opportunity except the beginning that produces with write address to read the address, and all the other all are the same.Like this, produce behind the generation write address earlier and read the address, just can be inserted into the IQ data of back level RRU in the RRU frame at the corresponding levels reliably.After the IQ data of back level light mouth input are changed through such dual port RAM, enable control, form a complete frame, send to previous stage RRU or BBU with the IQ data of the corresponding levels by the IQ data forwarding.

(3) transmit the generation that enables

Forwarding enables controlling the framing of data, supposes to transmit to enable to transmit the IQ data of RRU at the corresponding levels during low level for high level is to transmit the IQ data that back level RRU sends over.According to number producing by the local carrier of BBU configuration, when in a sub-group,, to transmit so and enable to be low level if corresponding position is local carrier wave, remaining carrier position is a high level.So just produced the forwarding enable signal.

Though the disclosed execution mode of the present invention as above, described content is not in order to limit.Have in any the technical field of the invention and know the knowledgeable usually, under the prerequisite that does not break away from the disclosed spirit and scope of the present invention, can do a little change and retouching in form and on the details what implement.Scope of patent protection of the present invention, still must with appending claims the person of being defined be as the criterion.

Claims (7)

1, a kind of IQ data transmission method of Remote Radio Unit is characterized in that:

Remote Radio Unit cascaded up in the chain mode is connected to baseband pool unit, and the shared carrier number of IQ data of Remote Radio Unit at different levels is distributed by baseband pool unit, and the IQ data are organized according to frame format and transmitted.

2, the method for claim 1 is characterized in that:

Described Remote Radio Unit is realized by extensive Field Programmable Gate Array.

3, the method for claim 1 is characterized in that:

The data of every grade of Remote Radio Unit are combined into a complete frame according to frame format.

4, the method for claim 1 is characterized in that:

The carrier number that every grade of Remote Radio Unit takies does not repeat.

5, the method for claim 1 is characterized in that:

The IQ data are from the baseband pool unit to the Remote Radio Unit or from Remote Radio Unit at the corresponding levels the down direction to back level Remote Radio Unit:

Remote Radio Unit at the corresponding levels obtains the IQ data according to carrier number,, the IQ data is converted to analog if signal launches through phase-locked loop and after with the road clock synchronization at local clock, simultaneously the IQ data forwarding is arrived back level Remote Radio Unit;

The IQ data are from the Remote Radio Unit to the baseband pool unit or from Remote Radio Unit at the corresponding levels the up direction to the prime Remote Radio Unit:

The IQ data of Remote Radio Unit at the corresponding levels are converted to digital medium-frequency signal, local clock through phase-locked loop with the road clock synchronization after, the carrier number of occupying according to the corresponding levels and the position of the up frame head of Remote Radio Unit at the corresponding levels, the IQ data are inserted into corresponding carrier wave allocation position launch, simultaneously with the IQ data forwarding to the prime Remote Radio Unit.

6, method as claimed in claim 5 is characterized in that:

The IQ data are carried out buffer memory by pushup storage, to eliminate the clock jitter that phase-locked loop causes.

7, method as claimed in claim 5 is characterized in that:

In the described up direction,, the IQ data that the IQ data and the back level Remote Radio Unit of Remote Radio Unit at the corresponding levels sends over are transmitted respectively by the control of the forwarding enable signal that number produces by the local carrier of baseband pool unit configuration.

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