CN102340830B - Dynamic spectrum using method between wireless access technology - Google Patents

Abstract

The invention discloses the dynamic spectrum using method between a kind of wireless access technology, the method comprises the following steps: step one, produces depression, form the depression on frequency domain on the idle frequency band of the first system；Step 2, second system uses the frequency band at the recessed position place on the frequency domain of described the first system。The present invention can effectively be polymerized the discontinuous bandwidth under multiple access technology when not changing existing access technology, is commonly referred to " aggregated bandwidth ", reaches effectively to use the purpose of frequency spectrum, and the complexity of method is not significantly increased yet。Additionally, the frequency spectrum resource that the present invention can make multiple wireless access system is effectively shared。

Description

Dynamic spectrum using method between wireless access technology

Technical field

The invention belongs to wireless communication field, relate to the dynamic spectrum using method between a kind of wireless access technology。

Background technology

Frequency spectrum is a kind of very rare resource, it is necessary to used efficiently, otherwise cannot meet growing demand。Current frequency spectrum use method is: provide frequency spectrum resource block one section fixing for each new service。Along with increasing based on the service of frequency spectrum and the quick of equipment, frequency spectrum resource is about to exhaust。Additionally, the frequency spectrum resource for some application reservation is seldom used, and the frequency spectrum resource that meanwhile utilization rate is higher is very nervous。Along with the increase of data business volume, frequency spectrum how is more efficiently used to become a urgent problem。In recent years, flexible spectrum uses this problem to receive attention substantially in research field, the research of spectrum management techniques more than ten years have been continue for, and create and be assigned to the multiple different frequency spectrum resource methods of salary distribution such as dynamic frequency spectrum deployment from dynamic channel, such as software radio and cognitive radio etc.。But the frequency spectrum resource seldom obtaining using retained for some application is still a kind of waste, also without being fully utilized。

Summary of the invention

The technical problem to be solved is: provide the dynamic spectrum using method between a kind of wireless access technology, and the method can be polymerized the discontinuous bandwidth under multiple access technology effectively。

For solving above-mentioned technical problem, the present invention adopts the following technical scheme that。

Dynamic spectrum using method between a kind of wireless access technology comprises the following steps:

Step one, produces depression on the idle frequency band of the first system, forms the depression on frequency domain；

Step 2, second system uses the frequency band at the recessed position place on the frequency domain of described the first system。

As a preferred embodiment of the present invention, the production method of the depression on the frequency domain of described the first system is: by the subcarrier zero setting on the idle frequency band of described the first system, form the depression on frequency domain。

As the another kind of preferred version of the present invention, the production method of the depression on the frequency domain of described the first system is: utilizes depression pulse shaping filter that described the first system carries out frequency domain filtering, forms the depression on frequency domain。

As another preferred version of the present invention, the production method of the depression on the frequency domain of described the first system is:

First by the subcarrier zero setting on the idle frequency band of described the first system；

The subcarrier of described zero setting is filtered by recycling depression pulse shaping filter。

As another preferred version of the present invention, described depression pulse shaping filter is:

$g_{\mathrm{bi}}\left(n\frac{T}{M}\right)=g_{\mathrm{bi}}\left[n\right]=\mathrm{IFFT}\left(\mathrm{Win}\right[k]\×\frac{R_{\mathrm{HG}}\left[k\right]}{H\left[k\right]}),0\≤n,k\≤\mathrm{\γM}-1$

Wherein, $H\left[k\right]=\mathrm{FFT}\left(h_{\mathrm{bi}}\right[n\left]\right)=\underset{n=0}{\overset{L-1}{\mathrm{\Σ}}}h\left(n\frac{T}{M}\right)e^{-\frac{j2\mathrm{\πnk}}{\mathrm{\γM}}},0\≤n\≤L-\mathrm{1,0},k\≤\mathrm{\γM}-1;$

$R_{\mathrm{HG}}\left[k\right]=R_{\mathrm{HG}}\left(f\right){|}_{f=k\frac{1}{\mathrm{\γM}}\frac{M}{T}},0\≤k\≤\mathrm{\γM}-1;$

$R_{\mathrm{HG}}\left(f\right)=\left\{\begin{array}{c}1,\mathrm{if}\left|f\right|\&le;(1-\mathrm{\&alpha;})/2T\\ \frac{1}{2}[1+\cos \left(\frac{\mathrm{\&pi;}\left(2T\right|f\left|\right)-1+\mathrm{\&alpha;}}{2\mathrm{\&alpha;}}\right)],\mathrm{if}(1-\mathrm{\&alpha;})\\ 0,\mathrm{if}\left|f\right|>(1+\mathrm{\&alpha;})/2T\end{array}/2T<\left|f\right|\&le;(1+\mathrm{\&alpha;})/2T\right.$

F represents that frequency, α represent that rolloff-factor, T represent the modulation intervals cycle, and M represents that number of subchannels, n represent time-domain sampling point sequence number, and k represents frequency domain sample point sequence number, and γ is a coefficient, and L represents filter length。

As another preferred version of the present invention, described the first system is gsm system, and second system is LTE system。

The beneficial effects of the present invention is: the discontinuous bandwidth that the present invention can effectively be polymerized under multiple access technology when not changing existing access technology, it is commonly referred to " aggregated bandwidth ", reach effectively to use the purpose of frequency spectrum, and the complexity of method is not significantly increased yet。

The present invention another advantage is that: the present invention can make the frequency spectrum resource of multiple wireless access system effectively be shared。

Accompanying drawing explanation

Fig. 1 is the scene schematic diagram that LTE system coexists with gsm system；

Fig. 2 is the LTE system flow schematic diagram with gsm system of hot zones；

Fig. 3 is that the dynamic spectrum between LTE system and gsm system uses schematic diagram；

Fig. 4 is that in GSM frequency range, 1 block is set as zero, the schematic diagram of forming frequency depression；

Fig. 5 is that in GSM frequency range, 2 blocks are set as zero, the schematic diagram of forming frequency depression；

Fig. 6 is that in GSM frequency range, 1 block is set as zero, and uses depression pulse shaping filter, the schematic diagram of forming frequency depression；

Fig. 7 is that in GSM frequency range, 6 subcarriers are set as zero, and uses depression pulse shaping filter, the schematic diagram of forming frequency depression；

Fig. 8 is the schematic diagram that traditional pulse shaping filter is used for the untapped subcarrier of the LTE after arranging；

Fig. 9 is the schematic diagram that depression forming filter is used for the untapped subcarrier of the LTE after arranging；

Figure 10 is the amplitude-frequency response figure of depression pulse shaping filter；

Figure 11 is the frequency response curve of transmitting filter, receiving filter and raised cosine filter；

Figure 12 launches filter pulse response and receives the crosscorrelation curve chart of impulse response。

Detailed description of the invention

Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described in further detail。

By the present invention in that with new pulse shaping filter and vacate OFDM subcarrier, frequency domain producing depression, reaches the purpose of aggregated bandwidth with this；Meanwhile, it is can also be applied to specific multicarrier (OFDMA) system, the performance of final polymerization is strengthened。Present invention could apply to the system such as 2G, 3GPP Long Term Evolution (Long-TermEvolution, LTE) and LTE enhancement mode (LTE-advanced)。

The use environment of the present invention is described below:

GSM (is operated in 900MHz frequency range) and LTE (being operated in 2GHz frequency range) is it is intended that the signal of area offer on a large scale covers。Along with the increase of LTE number of users, the traffic load of LTE system is more and more heavier, especially in some hot spot regions。And meanwhile, owing to gsm system user shifts toward LTE system, therefore the frequency spectrum utilization rate of gsm system declines。

The dynamic spectrum using method that the present invention proposes can promote LTE system in hot spot region service quality。The present invention proposes, and in hot spot region, LTE system can use the band segment using gsm system outside original frequency spectrum resource, and now GSM still can use remaining frequency range。Simulation result shows, LTE system is after the method using the present invention to propose, it is possible to simply and efficiently GSM frequency range is used for LTE system。Dynamic spectrum operational version proposed by the invention can directly apply to ofdm system, uses and includes the registration of GSM900MHz or unregistered frequency range, such as WCDMA frequency range。

As it is shown in figure 1, LTE system and gsm system coexist, light color represents the frequency range distributing to LTE, and the frequency range of GSM is distributed in dark expression。The working frequency range of LTE is positioned near 2GHz, and the working frequency range of GSM is positioned near 900MHz。LTE system and gsm system all provide signal to cover for this panel region。It is contemplated that increasing user will be had future to favor LTE system rather than gsm system, because LTE can bring user better Consumer's Experience。Therefore along with GSM user constantly migrates toward LTE system, the flow of LTE is increasing, and the flow of gsm system is more and more less, and this is by little for the applied load causing GSM frequency range, and the applied load of LTE frequency range is big。

Embodiment one

The present embodiment provides the dynamic spectrum using method between a kind of wireless access technology, as shown in Figures 2 and 3。Assuming that the traffic load of the LTE of some community (such as LTE hot zones) is very big, the used frequency range of LTE is difficult to meet the demand of all LTE users。In this case, LTE can use GSM frequency range, supplementing as the original frequency range of LTE。In Fig. 2 and Fig. 3 (A), LTE extended frequency band dark color represents, in these communities (hot zones such as LTE), the remaining frequency range of GSM is still used by gsm system；The remaining frequency range light color of GSM represents。It is constant that other community outside hot zones still maintains the distribution of original frequency spectrum, as shown in Fig. 2 and Fig. 3 (B)。Fig. 3 (A) represents the frequency spectrum service condition of LTE hot zones, and Fig. 3 (B) represents the frequency spectrum service condition of other communities except LTE hot zones。LTE is when hot zones uses the band segment of GSM, and the used frequency range of LTE is discrete, and as a part is positioned at 2GHz, and a part is positioned at 900MHz。As it is shown on figure 3, in the 900MHz frequency band of GSM, the multiplex mode of LTE and GSM signal should be frequency division multiplexing (FDM)。

For the purpose reaching to coexist in same section of frequency band, the dynamic spectrum using method between the wireless access technology described in the present embodiment includes following 2 steps。

The first step: LTE system vacates some subcarriers the subcarrier zero setting that will vacate, forms depression。

Obviously, in LTE, unappropriated OFDM subcarrier can pass through reasonably planning and form the depression on frequency domain, as shown in Figure 4 and Figure 5。Fig. 4 and Fig. 5 gives two kinds of simulation results, and namely after 12 and 24 OFDM subcarriers (namely respectively 1 and 2 Resource Block, including DC component) are set as zero by transmitting terminal respectively, the frequency domain defining-5.5dB and-9.5dB caves in。The two depression desire bandwidth respectively 195KHz and 375KHz。Now, GSM signal just can send in the frequency band that the frequency of LTE caves in。

Assume that this Hot Spot only uses a GSM subcarrier (200KHz), and this GSM subcarrier is positioned at the center of 900MHz, as shown in Fig. 3 (A), so this Hot Spot not only can use whole LTE subcarrier (2GHz), it is also possible to all the other GSM subcarriers (900MHz except 200KHz) frequency range is used to LTE system。

Second step: adopt depression pulse shaping filter at recessed position place。

Allowing LTE use one depression pulse shaping filter at recessed position place, this will bring extra gain at recessed position place, and as shown in Figure 6, this scheme can avoid producing between different system interference。In figure 6, simultaneously by vacant subcarrier zero setting, and have employed depression pulse shaping, depression bandwidth is fixed as 195KHz。In order to produce the frequency decline of nearly-10dB, it is necessary to use 12 vacant subcarriers and depression pulse shaping, as shown in Figure 6 simultaneously。In order to produce the frequency decline of nearly-5.5dB, it is necessary to use 6 vacant subcarriers and depression pulse shaping, as shown in Figure 7 simultaneously。

Fig. 4, Fig. 5 and Fig. 6 are compared, it is easy to find that depression filtering shapes and can obtain extra fading gains。Frequency as obtained-10dB declines, when using depression pulse shaping, it is only necessary to obtaining 12 LTE subcarriers in 900MHz frequency range, this will make the LTE utilization rate at the used spread-spectrum of 900MHz frequency range be increased to 84.21% from 68.42%, as shown in table 1。Frequency as obtained-5.5dB declines, when using depression pulse shaping, it is only necessary to obtaining 6 LTE subcarriers in 900MHz frequency range, this will make the LTE utilization rate at the used spread-spectrum of 900MHz frequency range be increased to 92.11% from 84.21%, as shown in table 2。Obviously, use depression pulse shaping and OFDM subcarrier zero setting can obtain the decline of better frequency simultaneously, and obtain the higher availability of frequency spectrum。

Table 1: the performance evaluation (frequency decline ≈-10dB) that depression generates

Table 2: the performance evaluation (frequency decline ≈-5.5dB) that depression generates

As long as some subcarrier in GSM frequency range is set as zero, LTE just can more easily realize the arrangement of unappropriated subcarrier。The quantity of these subcarriers being set to zero is determined by the bandwidth of GSM。

Transmitting terminal spectral characteristic is finally by the restriction of pulse shaping filter, as shown in Figure 8 and Figure 9。Fig. 8 and Fig. 9 employs traditional square root raised cosine filter and depression pulse shaping filter respectively。If being evolved on frequency domain by traditional raised cosine pulse forming filter to exist the FIR filter of depression, then the same with Fig. 9 can obtain higher fading gains。The design to conventional FIR filter can be passed through and obtain this pulse shaping filter, as shown in Figure 10。The receiving filter shown in Figure 11 can be produced with raised cosine pulse。

Traditional raised cosine pulse forming filter is:

$R_{\mathrm{HG}}\left(f\right)=\left\{\begin{array}{c}1,\mathrm{if}\left|f\right|\&le;(1-\mathrm{\&alpha;})/2T\\ \frac{1}{2}[1+\cos \left(\frac{\mathrm{\&pi;}\left(2T\right|f\left|\right)-1+\mathrm{\&alpha;}}{2\mathrm{\&alpha;}}\right)],\mathrm{if}(1-\mathrm{\&alpha;})\\ 0,\mathrm{if}\left|f\right|>(1+\mathrm{\&alpha;})/2T\end{array}/2T<\left|f\right|\&le;(1+\mathrm{\&alpha;})/2T\right.$

Wherein, f represents that frequency, α represent that rolloff-factor, T represent the modulation intervals cycle。

The FIR filter (namely cave in pulse shaping filter) that there is depression on the frequency domain developed into by traditional raised cosine arteries and veins wave filter is:

$g_{\mathrm{bi}}\left(n\frac{T}{M}\right)=g_{\mathrm{bi}}\left[n\right]=\mathrm{IFFT}\left(\mathrm{Win}\right[k]\&times;\frac{R_{\mathrm{HG}}\left[k\right]}{H\left[k\right]}),0\&le;n,k\&le;\mathrm{\&gamma;M}-1$

Wherein,Win [k] is window function, and h is impulse Response Function；M represents that number of subchannels, n represent time-domain sampling point sequence number, and k represents frequency domain sample point sequence number, and γ is a coefficient, and L represents filter length。

Now, transmitting filter and the receiving filter converted quadrature in time domain is retained。Figure 12 describes the crosscorrelation between the impulse response of emission filter and the impulse response of receiving filter。Although emission filter and receiving filter have different impulse response, but its converted quadrature is enough to limit intersymbol interference (Inter-SymbolInterference, ISI)。

The present invention can effectively be polymerized the discontinuous bandwidth under multiple access technology when not changing existing access technology, is commonly referred to " aggregated bandwidth ", reaches effectively to use the purpose of frequency spectrum, and the complexity of method is not significantly increased yet。Additionally, the frequency spectrum resource that the present invention can make multiple wireless access system is effectively shared。

Here description of the invention and application is illustrative, is not wishing to limit the scope of the invention in above-described embodiment。The deformation of embodiments disclosed herein and change are possible, for those skilled in the art embodiment replace and the various parts of equivalence are known。It should be appreciated by the person skilled in the art that when without departing from the spirit of the present invention or substitutive characteristics, the present invention can otherwise, structure, layout, ratio, and realize with other elements, material and parts。

Claims (3)

1. the dynamic spectrum using method between a wireless access technology, it is characterised in that said method comprising the steps of:

Step one, produces depression on the idle frequency band of the first system, forms the depression on frequency domain；The production method of the depression on the frequency domain of described the first system is: utilizes depression pulse shaping filter that described the first system carries out frequency domain filtering, forms the depression on frequency domain；Described depression pulse shaping filter is:

$g_{bi}\left(n\frac{T}{M}\right)=g_{bi}\&lsqb;n\&rsqb;=IFFT(Win\&lsqb;k\&rsqb;\&times;\frac{R_{HG}\&lsqb;k\&rsqb;}{H\&lsqb;k\&rsqb;}),$ 0≤n,k≤γM-1

Wherein,0≤n≤L-1,0≤k≤γ M-1；Win [k] is window function, and h is impulse Response Function；0≤k≤γ M-1；

$R_{HG}\left(f\right)=\left\{\begin{array}{c}1,if\left|f\right|\&le;(1-\mathrm{\&alpha;})/2T\\ \frac{1}{2}\&lsqb;1+cos\left(\frac{\mathrm{\&pi;}\left(2T\right|f\left|\right)-1+\mathrm{\&alpha;}}{2\mathrm{\&alpha;}}\right)\&rsqb;,if(1-\mathrm{\&alpha;})/2T<\left|f\right|\&le;(1+\mathrm{\&alpha;})/2T\\ 0,if\left|f\right|>(1+\mathrm{\&alpha;})/2T\end{array}\right.$

F represents that frequency, α represent that rolloff-factor, T represent the modulation intervals cycle, and M represents that number of subchannels, n represent time-domain sampling point sequence number, and k represents frequency domain sample point sequence number, and γ is a coefficient, and L represents filter length；

Step 2, second system uses the frequency band at the recessed position place on the frequency domain of described the first system。

2. the dynamic spectrum using method between wireless access technology according to claim 1, it is characterised in that: the production method of the depression on the frequency domain of described the first system is:

First by the subcarrier zero setting on the idle frequency band of described the first system；

The subcarrier of described zero setting is filtered by recycling depression pulse shaping filter。

3. the dynamic spectrum using method between the wireless access technology according to claim 1 to 2 any one, it is characterised in that: described the first system is gsm system, and second system is LTE system。