CN106936758B

CN106936758B - Method and device for improving radio frequency index of EDGE transmitter

Info

Publication number: CN106936758B
Application number: CN201511018461.2A
Authority: CN
Inventors: 陈文杰; 刘伟
Original assignee: Leadcore Technology Co Ltd; Datang Semiconductor Design Co Ltd
Current assignee: Chenxin Technology Co ltd
Priority date: 2015-12-29
Filing date: 2015-12-29
Publication date: 2019-12-13
Anticipated expiration: 2035-12-29
Also published as: CN106936758A

Abstract

The invention relates to a method and a device for improving radio frequency indexes of an EDGE transmitter. The method comprises the following steps: optimizing the filling bits according to the relation between the EDGE modulated signal and the radio frequency output signal; synthesizing the optimized padding bits and the valid data modulation bits into modulation bits; and obtaining an optimized rising switching spectrum and falling switching spectrum using the synthesized modulation bits.

Description

Method and device for improving radio frequency index of EDGE transmitter

Technical Field

The present invention relates to the field of mobile communications, and in particular, to a method and apparatus for improving radio frequency indicators of an EDGE transmitter.

Background

EDGE (Enhanced Data Rate for GSM Evolution) is a transition from GSM to 3G.

The EDGE switching spectrum measurement method defined in the GSM specification is to measure the peak hold power at a certain bandwidth at a certain position off the center frequency in the time domain. The specification further describes that the switching spectrum is defined as the peak power of the transient when the power is switched. As shown in fig. 1, the switching spectrum is the peak power resulting from both the ramp up (ramp up) and ramp down (ramp down) of the burst power from off to on. According to the EDGE switching spectrum requirements of specification 3GPP 51.010, the switching transient period including the Ramp up and Ramp down (Ramp) is the worst position of the switching spectrum in general.

The existing method for debugging the switching spectrum is to improve the switching spectrum by debugging the time domain characteristics of a Ramp part. The adopted method comprises debugging the Ramp curve and debugging the Ramp timing sequence. The debugging Ramp curve is a time-domain characteristic that changes the actual Ramp power through a time-gain sequence (Ramp curve) inside the chip. The Ramp timing is debugged, i.e. the time domain characteristic of the power is changed by adjusting the relative relationship between the Ramp curve and the filling bits (dummy bits) in the burst.

These two techniques have the following disadvantages:

First, the current method of debugging Ramp curve can effectively improve the switching spectrum, but because EDGE modulation and Ramp power Ramp are implemented in the transmitter, linearity of Ramp curve parameters and actual output power is guaranteed by the transmitter. In practice, the Ramp curve of a part of transmitters and the actual output power are in a nonlinear relation, weak adjustment under certain Ramp voltages can cause power abrupt change, and the similarity between the actual output power curve and the Ramp curve is too poor, which causes great difficulty in debugging. Meanwhile, in order to ensure the time domain index of the power, the Ramp curve cannot be regulated violently.

Secondly, the Ramp time sequence is debugged, namely the output Ramp time domain characteristic is changed by changing the initial position of the Ramp, the debugging mode is mainly trial, the efficiency is low, and meanwhile, the debugging is also hampered by the time domain index of the power.

Disclosure of Invention

The invention aims to provide a method and a device for improving the radio frequency index of an EDGE transmitter.

The technical scheme adopted by the invention for solving the technical problems is a method for improving the radio frequency index of an EDGE transmitter, which comprises the following steps: optimizing the filling bits according to the relation between the EDGE modulated signal and the radio frequency output signal; synthesizing the optimized padding bits and the valid data modulation bits into modulation bits; and obtaining an optimized rising switching spectrum and falling switching spectrum using the synthesized modulation bits.

In an embodiment of the present invention, the step of optimizing the padding bits includes: the length of the padding bits is optimized.

In an embodiment of the present invention, the step of optimizing the length of the padding bits during the downhill comprises: configuring a free part of the padding bits; the length of the filler bits during the defined downhill slope is not greater than the length of the free part of the filler bits.

In an embodiment of the present invention, the step of optimizing the padding bits further comprises obtaining the optimized padding bits by traversing the plurality of groups of sequences of padding bits.

In one embodiment of the invention, the traversal method comprises a traversal calculation verification method and a direct traversal test method.

In an embodiment of the present invention, the step of optimizing the padding bits includes: and outputting a modulation bit sequence comprising three subsections which are sequentially arranged, wherein the first field is a filling bit sequence of a descending slope of a previous time slot, the second subsection is a part filled with '1' in a non-climbing slope, and the third subsection is a filling bit sequence of an ascending slope of a next time slot.

In an embodiment of the present invention, the radio frequency indicators include a switching spectrum, a radiation spectrum, and a spurious indicator.

The invention also provides a device for improving the radio frequency index of the EDGE transmitter, which comprises an optimized filling bit generator, a modulation bit synthesizer and a radio frequency signal spectrum generating device. The optimized filler bit generator optimizes the filler bits according to the relationship between the EDGE modulated signal and the RF output signal. The modulation bit synthesizer synthesizes the optimized pad bits and the valid data modulation bits into modulation bits. The radio frequency signal spectrum generation device obtains an optimized rising switching spectrum and a falling switching spectrum by using the synthesized modulation bits.

In an embodiment of the invention, the optimized filler bit generator optimizes the length of the filler bits.

In an embodiment of the invention, the optimized filler bit generator optimizes the length of the filler bits during the downhill slope as follows: configuring a free part of the padding bits; the length of the filler bits during the defined downhill slope is not greater than the length of the free part of the filler bits.

In an embodiment of the present invention, the optimized padding bit generator outputs a modulation bit sequence including three sequentially arranged sub-segments, where the first field is a padding bit sequence of a previous time slot descending slope, the second sub-segment is a part filled with "1" for non-climbing slope, and the third sub-segment is a padding bit sequence of a next time slot ascending slope.

By adopting the technical scheme, compared with the prior art, the EDGE switch spectrum can be improved by modifying the filling bits, and the filling bit sequence can be independently adjusted to optimize the switch spectrum under the condition of not adjusting an EDGE climbing curve and climbing timing.

Drawings

in order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below, wherein:

Fig. 1 is a specification definition diagram of a switching spectrum.

Figure 2 is a modulation bit and power diagram for a GSM/EDGE burst.

Fig. 3 is a diagram of modulation bits and power between 2 slots for GSM/EDGE.

FIG. 4 shows N in EDGE-GMSK mode_{ramp_down_free}Schematic diagram of the calculation of (1).

Fig. 5 is a schematic diagram of the formation of an EDGE radio frequency signal spectrum.

Fig. 6 is a diagram of a system architecture incorporating an optimized pad bit generator, in accordance with an embodiment of the present invention.

Fig. 7 is a functional diagram of an optimized pad bit generator.

Fig. 8 is a schematic diagram of an input-output interface of an optimized pad bit generator.

FIG. 9 is a computational schematic of a traversal computational verification method.

Fig. 10 is a diagram of a test platform architecture for a direct traversal method.

Detailed Description

Embodiments of the present invention describe methods and apparatus for improving EDGE transmitter switch spectrum radio frequency indicators. According to this method, padding bits (dummy bits) are used to consider improving the switching spectrum characteristics.

Specifically, the optimization of the power spectrum of the power ramp section can be caused by adjusting the padding bits of the power ramp section, thereby achieving the purpose of improving the EDGE switching spectrum. And the modification of the filling bits of the power ramp part can completely meet the requirement of the specification on the state of the GMSK modulator.

Figure 2 is a modulation bit and power diagram for a GSM/EDGE burst. As shown in fig. 2, one GSM/EDGE burst (burst) includes n slots (n is a natural number from 1 to 4). The transmitted data is represented by transmission burst modulation bits d (i), which may be n pieces of useful data d_useful(i) (i ═ 1,2,3,..., n) and n +1 pieces of padding bit data d_dummy(j) (i ═ 1,2, 3.., n +1) in this order. Meanwhile, the transmitted power is represented by transmission burst power y (t). It can be seen that y (t) can be defined by n segments of useful power y_useful(t) and a filling power y of n +1 segments_dummy(t) are arranged in order. d (i) and y (t) have a certain time sequence corresponding relation: d_useful(i) corresponds in time to y_useful(t)。d_dummy(i) (length N)_dummy) Corresponds in time to y_dummy(t) (duration Tdummy).

Wherein the padding bits (with d)_dummy(i) Representation) are the parts of modulation bits (modulation bits) that define the useful part of the data of the burst outside the beginning and end of the EDGE and GMSK modulation. Y between two time slots if further analyzed_dummy(t) may consist of 3 parts, as shown in FIG. 3 as y_{ramp_down}(i-1)、y_guard(t) and y_{ramp_up}(i) Respectively representing a downward slope of a previous time slot, a guard interval, and an upward slope of a next time slot. y is_{ramp_up}And y_{ramp_down}The time length of the modulation is determined by a radio frequency chip (RFIC), and the rising and falling of the GMSK modulation mode are T_{ramp_GMSK}For EDGE modulation mode, the up-down slope is T_{ramp_EDGE}。y_{ramp_up}and y_{ramp_down}The part is that of the power switching transient, which according to the specification is defined as the cause of the switch spectrum degradation.

D (t) can be determined according to the time sequence relation of y (t) and d (i)_dummy(i) Also divided into 3 sections: d_{ramp_down}(i-1)、d_{dummy_guard}(i) And d_{ramp_up}(i) Let d be known_{ramp_down}And d_{ramp_up}Partly one of the causes of the degradation of the switching spectrum. Corresponding to y (t), GMSK modulation mode up-down slope length N_{ramp_GMSK}EDGE toneSystem mode N_{ramp_EDGE}And T_{ramp_GMSK}And T_{ramp_EDGE}The relationship of (c) is shown in equations 1 to 3. Tsymbol in the formula is 6/1625ms, which is GMSK/EDGE symbol period.

Equation 1

Equation 2

Equation 3

The function ceil in equations 1 to 3 represents an upward integer since the padding data must be in integer units. In general N_{ramp_GMSK}And N_{ramp_EDGE}At 3 or 4 symbols.

The 3GPP specification requires all "1" for the padding bits under GMSK modulation to guarantee the initial state of the differential encoder in GMSK modulator. No requirements are placed on the filler bit content for the EDGE modulation specification because the EDGE modulator does not have a differential encoder section and the initial state of the EDGE modulator does not need to be guaranteed. According to the standard principle, a radio frequency chip is set to define a Tgmsk _ mod _ adv parameter as the advance time of a GMSK modulator, and when a filling bit is followed by a time slot d_useful(i) For GMSK modulation, the specification requires that the fill-in data must be all "1" during Tgmsk _ mod _ adv. And the filling bits of the part outside the Tgmsk _ mod _ adv period can be changed without influencing the GMSK modulation function, which is in accordance with the requirement of the specification. Since this time is substantially at y_{ramp_down}(i-1) position, so the length of the segment is defined as N_{ramp_down_free}And represents a portion in which the padding bits can be freely configured during the downhill slope. As shown in figure 4 and the EDGE-GMSK time slot shown in equation 4.

Equation 4

Formula (II)In 4, the function floor represents a downward integer, which is "1" to ensure that the padding data in Tgmsk _ mod _ adv is fixed. In general N_{ramp_down_free}In 2-4 symbols.

According to an embodiment of the present invention, d is modified_{ramp_up}And d_{ramp_down}The switching spectrum is improved in a mode of optimizing the value. To satisfy the state problem of GMSK modulator in EDGE-GMSK switching mode, the d of EDGE is needed_{ramp_down}Length N of_{ramp_EDGE}Is limited to be N_{ramp_down_opt}As shown in fig. 4 and equation 5.

N_{ramp_down_opt}＝min(N_{ramp_down_free},N_{ramp_EDGE}) Equation 5

This requirement is not present for the downhill part of the EDGE mode, so d can be optimized_{ramp_up}Length N of_{ramp_up_opt}As shown in equation 6.

N_{ramp_up_opt}＝N_{ramp_EDGE}Equation 6

Fig. 5 is a schematic diagram of the formation of an EDGE radio frequency signal spectrum. Referring to fig. 5, the mapping relationship of d (i) - > x (t) is an EDGE modulation process, where the constellation symbol mapping (without shaping filtering) is completed by transmitting burst modulation bits according to the definition of 3GPP specification 45.004, and becomes a process of EDGE modulated signal x (t). The units referred to in fig. 5 comprise an EDGE modulator 51, a pulse shaping filter 52, a ramp unit 53 and a radio frequency modulator 54. The time domain relationship between the rf output signal y (t) and the input EDGE modulated signal x (t) is shown in equation 7.

y(t)＝x(t)*ps(t)×ramp(t)×[h_Φ(t)·e^jωt]Equation 7

Ps (t) in equation 7 is a parameter of the EDGE pulse-shaping filter 52, defined by specification 3GPP 45.004. Ramp (t) is the amplitude envelope during hill climbing. h is_φAnd (t) is distortion characteristics such as phase noise of the radio frequency chip. e.g. of the type^jωtIs the frequency translation effect of the mixer. ps (t), h_φ(t) and e^jωtThe radio frequency chip and the system working state determine that debugging can not be carried out in principle, and Ramp (t) becomes the only debugging means for the switch spectrum at present.

According to the formula7, by obtaining optimized padding bits d in d (i)_{ramp_up_opt}And d_{ramp_down_opt}Get optimized y_{ramp_up}And y_{ramp_down}And the purpose of improving the EDGE switch spectrum is achieved. The implementation means may be referred to as an "optimized filler bit generator" for generating optimized filler bits within the filler bit region.

Fig. 6 is a diagram of a system architecture incorporating an optimized pad bit generator, in accordance with an embodiment of the present invention. As shown in fig. 6, the units involved in the system include an optimized pad bit generator 61, a modulation bit synthesizer 62, an EDGE modulator 63, a pulse shaping filter 64, a ramp unit 65 and a radio frequency modulator 66. An optimized filler bit generator 61 is provided as one input to a modulation bit synthesizer 62, and the other input to the modulation bit synthesizer 62 is the N slot valid data modulation bits. The modulation bit synthesizer 62 is then connected in series with an EDGE modulator 63, a pulse shaping filter 64, a ramp unit 65 and a radio frequency modulator 66. These components 63-66 are conventional EDGE radio frequency signal spectrum generating devices.

Fig. 7 is a functional diagram of an optimized pad bit generator. Referring to fig. 7, the optimized pad bit generator 61 can generate pad bits between respective slots.

The input-output characteristics of the optimized pad bit generator 61 are shown in fig. 8. There are 8 entries for the input parameters, listed below:

1) The padding bit region length (Ndummy) is obtained according to equation 1.

2) Modulation mode of previous time slot: mode _ type (i-1), the value is GMSK, EDGE or NONE. When the parameter is NONE, it represents that the padding bit region belongs to the head of the first slot.

3) Modulation mode of the latter slot): mode _ type (i), the value is GMSK, EDGE, or NONE. When the parameter is NONE, it represents that the padding bit region belongs to the end of the last slot.

4) EDGE modulation upslope optimized padding bit length: n is a radical of_{ramp_up_opt}Obtained according to equation 6.

5) EDGE modulation downhill optimization padding bit length: n is a radical of_{ramp_down_opt}According to the formula 5And (4) obtaining.

6) GMSK modulates the uphill and downhill fill bit length: n is a radical of_{ramp_GMSK}Obtained according to equation 2.

7) Optimal EDGE upslope padding bit sequence: d_{ramp_up_opt}(length N)_{ramp_up_opt})。

8) Optimal EDGE downhill padding bit sequence: d_{ramp_down_opt}(length N)_{ramp_down_opt})。

The output of the optimized filler bit generator 61 is a set of modulation bit sequences d_{dummy_opt}(i) And consists of a modulation bit sequence with 3 subsections arranged in sequence, as shown in formula 8.

d_{dummy_opt}(i)＝[d_{dummy_part1}(i),d_{dummy_part2}(i),d_{dummy_part3}(i)]Equation 8

The 3 subsegments of the optimized filler bit generator are illustrated as follows:

[1]Denotes d_{dummy_part1}(i) The method comprises the following steps The padding bit sequence of the previous time slot ramp down.

[2]denotes d_{dummy_part2}(i) The method comprises the following steps The non-ramp fills in the "1" portion.

[3]Denotes d_{dummy_part3}(i) The method comprises the following steps The padding bit sequence of the latter time slot ramp up.

The input-output relationship of the optimized pad bit generator is shown in table 1.

Table 1: optimizing input-output relationships of a pad bit generator

In the optimized filler bit generator 61, a parameter d is input_{ramp_up_opt}And d_{ramp_down_opt}There are 2 implementation methods: the method comprises a traversal calculation verification method and a direct traversal test method. The two methods involve the same set of traversal tables. The traversal table component is 2 traversal tables, an uphill traversal tableis in 8 states of each symbol of EDGE, and has N_{ramp_up_opt}Formed by symbolsA seed padding bit sequence; the downhill passing table is composed of 8 states of EDGE symbol, and N_{ramp_down_opt}Formed by symbolsA sequence of padding bits.

FIG. 9 is a computational schematic of a traversal computational verification method. As shown in fig. 9, h is a sum of parameters Ramp (t) and Ramp (t) of the actual transmission signal_Φ(t) extracting, on the basis of traversing of filling bits, solving y (t) through a formula 7 and calculating a switch spectrum index, sequencing the history table by taking the optimal switch spectrum index as a basis, and then carrying out actual verification to obtain d_{ramp_up_opt}And d_{ramp_down_opt}The method of (1). The traversal calculation verification method is characterized in that the main work is computational, the actual test quantity is not large, the efficiency is high, and the optimal performance cannot be achieved.

Fig. 10 is a diagram of a test platform architecture for a direct traversal method. As shown in fig. 10, the platform architecture is implemented by using a personal computer 1001 to merge EDGE burst valid data into d in a history table_{ramp_up}And d_{ramp_down}and then, the signals are transmitted by a baseband chip 1002 and a radio frequency chip 1003 of the terminal, and are measured by a meter (such as a frequency spectrograph or a comprehensive measuring instrument 1004) to obtain the switch spectrum index. Sorting the history table based on the optimal switch spectrum index to directly obtain the optimal d_{ramp_up_opt}And d_{ramp_down_opt}The method of (1). The direct measurement traversal method is characterized in that the optimal group in all data can be directly selected without extracting radio frequency parameters. But the test time is relatively long.

the method for improving the EDGE switch spectrum by modifying the padding bits in the embodiment of the invention can independently adjust the padding bit sequence to optimize the switch spectrum under the condition of not adjusting an EDGE climbing curve and climbing timing. If the climbing curve, the climbing timing and the filling bit sequence are adjusted simultaneously, the optimization can be larger than that of the index under the original debugging method. The invention can be widely applied to various EDGE radio frequency chips, and can effectively optimize the EDGE switch spectrum under the condition of poor EDGE climbing curve linearity. And because the method of adjusting the software device of the filling bit is adopted for realizing, the method is more flexible and has higher efficiency than the method of directly modifying the Ramp curve and adjusting the time sequence, the influence of the conventional debugging mode on indexes such as PVT and the like is avoided, and the system risk is reduced.

Although the above-described embodiments of the present invention are described in terms of EDGE switching spectra, it will be appreciated that the present invention also extends to methods of improving other indicators of EDGE, such as radiated spectra and spurs, by modifying the padding bits, and apparatus implemented in accordance with such principles.

Although the present invention has been described with respect to the preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A method for improving EDGE transmitter radio frequency specifications, comprising the steps of:

Optimizing the filling bits according to the relation between the EDGE modulated signal and the radio frequency output signal;

Synthesizing the optimized padding bits and the valid data modulation bits into modulation bits;

Optimized rising and falling switching spectra are obtained using the synthesized modulation bits.

2. The method of claim 1, wherein the step of optimizing the padding bits comprises: the length of the padding bits is optimized.

3. The method of claim 1, wherein the step of optimizing the length of the padding bits during the downhill comprises: configuring a free part of the padding bits; the length of the filler bits during the defined downhill slope is not greater than the length of the free part of the filler bits.

4. The method of claim 1, wherein the step of optimizing the pad bits further comprises obtaining optimized pad bits by traversing multiple sets of sequences of pad bits.

5. The method of claim 4, wherein the method of traversing comprises a traversal computational verification method and a direct traversal testing method.

6. The method of claim 1, wherein the step of optimizing the padding bits comprises: and outputting a modulation bit sequence comprising three subsections which are sequentially arranged, wherein the first field is a filling bit sequence of a descending slope of a previous time slot, the second subsection is a part filled with '1' in a non-climbing slope, and the third subsection is a filling bit sequence of an ascending slope of a next time slot.

7. The method of claim 1, wherein the radio frequency indicators include on-off spectra, radiation spectra, and spurious indicators.

8. An apparatus for improving EDGE transmitter radio frequency metrics, comprising:

An optimized filling bit generator, which optimizes the filling bit according to the relationship between EDGE modulated signal and radio frequency output signal;

a modulation bit synthesizer synthesizing the optimized padding bits and the effective data modulation bits into modulation bits; and

And the radio frequency signal spectrum generating device obtains an optimized rising switching spectrum and an optimized falling switching spectrum by utilizing the synthesized modulation bits.

9. The apparatus of claim 8, wherein the optimized pad bit generator optimizes a length of the pad bits.

10. The apparatus of claim 8, wherein the optimized pad bit generator optimizes the length of pad bits during a downhill slope as follows: configuring a free part of the padding bits; the length of the filler bits during the defined downhill slope is not greater than the length of the free part of the filler bits.

11. The apparatus of claim 8, wherein the optimized padding bit generator outputs a modulation bit sequence comprising three sequentially arranged sub-segments, wherein a first field is a padding bit sequence of a previous slot downslope, a second sub-segment is a part filled with "1" for non-hill climbing, and a third sub-segment is a padding bit sequence of a next slot upslope.

12. The apparatus of claim 8, wherein the radio frequency indicators include switching spectrum, radiation spectrum, and spurious indicators.