CN101374268A - Method for implementing high speed multimedia broadcast technique of CDMA2000 system - Google Patents

Abstract

The invention relates to a method for providing real-time broadcast service in a CDMA2000 mobile communication network. The method comprises the following steps: setting a professional broadcasting network in the prior CDMA2000 network, the broadcasting network adopting special carrier frequency and OFDM modulation technique to support high-speed multimedia broadcast service; and transmitting identical information by transmitters using the same frequency in all cells in the broadcasting network to achieve single-frequency full-domain coverage without dividing position regions, wherein the mobile terminal can move in among all cells in the broadcasting network without switching cells when achieving the single-frequency full-domain coverage by using the special carrier frequency. The broadcasting system and the communication system coexist in the same frequency band, and can share a station, equipment and an indoor distribution system. A broadcast receiving module in the terminal and the original receiving module can coexist in the same frequency band and can share an antenna.

Description

A kind of implementation method of high-speed multimedia broadcast technique under the CDMA2000 system

Technical field

The present invention relates to the digital multimedia radio transmission technical field, refer to provide in the CDMA2000 mobile communication system method of real time broadcasting service especially.

Background technology

At present, multi-media broadcasting service is just becoming the focus that the whole world is paid close attention to, and also is the mobile communications industry new growth point, and watches that by mobile phone multimedia broadcasting program will become new killer's level of " 3G " epoch and use.For how high-quality audio frequency and video service is provided, be a weakness of 3G system, this also is a key factor of restriction 3G system development, also is simultaneously one of major reason of extensively launching in the world the 4G research and development.

Multi-media broadcasting service is provided on portable terminal at present, mainly contains dual mode:

A kind of mode such as MBMS technology based on mobile radio communication, the shared cover of this type of technological merit covers facility and operation management platform, but shortcoming is also clearly:

The physical layer of existing communication system adopts the single carrier standard, and its anti-multipath time delay ability is difficult to support the wide area single frequency network;

Owing to adopt the single carrier demodulation technology, handle the multipath interference performance and mainly come adaptive equalizer.Therefore, the strong multidiameter delay that produces by single frequency network cause receiving terminal realize complicated, power consumption is high;

The availability of frequency spectrum is low, is difficult to guarantee the audio frequency and video quality of service of two-forty (information source speed is at least 384Kbps);

Receiver sensitivity under the two-forty audio frequency and video business is low;

System realizes complicated, need carry out software upgrading to core net, Access Network, and increases relevant device.

Another is based on system of broadcasting network, and this type of technology is to pay close attention to a more class technology now in the world, and typical technology comprises DVB-H, the MediaFLO of QualCom, the T-DMB of Korea S, the ISDB-T of Japan etc. in Europe.The domestic T-MMB that Beijing new coastline is arranged, the DMB-T/H of Tsing-Hua University etc.The common feature of above-mentioned technology is all to have adopted the OFDM modulation technique, and advantage is to have natural good support ability for single frequency network, and high-quality video broadcast program can be provided, and this type of technical disadvantages is:

When radio network and mobile radio communication carried out independent networking respectively, the frequency protection band that needs 20MHz at least caused the serious waste of frequency resource with the interference between the opposing two system;

The two independent networking needs separate transmit network of two covers and blind area to mend some covering facility, two cover operation management platforms, and this repeated construction must cause the cost of arranging net very expensive.

Above-mentioned T-MMB technology is by Beijing new coastline independent research, and the transmitter of T-MMB system, multiplexer, terminal comprise that receiving chip has all passed through outer product large power test, and test result is good.The T-MMB system adopts OFDM (OFDM:Orthogonal Frequency DivisionMultiplex) technology, in the 1.536MHz frequency band, for fixing or mobile the reception, provides multimedia services such as multichannel voice frequency, video and data.The broadcast channel physical layer transmitting terminal of T-MMB is finished the conversion of the business datum of input to the broadcast channel transmission signals.The input data through energy dissipation, forward error correction coding, time domain interweave, constellation mapping, frequency-domain-interleaving, differential modulation and OFDM modulation, be multiplexed into the transmission frame signal.This signal is modulated into and transmits (30MHz～3000MHz) through up-conversion.T-MMB transmitting terminal theory diagram as shown in Figure 1.

The transmission signals of broadcast channel physical layer is made up of transmission frame, and each transmission frame is made of continuous synchronizing channel of time, fast information channel in dab receiver and MSC.MSC is used for service data transmission, is made up of public interleaving frame, and each public interleaving frame comprises 24 milliseconds transmission data.According to business and networking requirement, the broadcast channel physical layer has four kinds of transmission modes available, support high-order modulating (QPSK, 8PSK and 16APSK), the channel error correction coding adopts deletes surplus convolutional encoding and low-density checksum (LDPC:LowDensity Parity Check) sign indicating number.The support of broadcast channel physical layer is fixing to receive and moves reception, and supports single frequency network (SFN:Single Frequency Network) networking model.

System works frequency aspect, the T-MMB system is by defining four kinds of transmission modes (as shown in table 1) to adapt to different frequency ranges.The band limits that system is suitable for is 30～3000MHz.

The transmission mode of table 1 T-MMB system

Parameter	Transmission mode I	Transmission mode II	The transmission mode formula III	Transmission mode IV
					The useful sub-carrier number of OFDM symbol	1536	384	192	768
The sub-carrier number of OFDM symbol	2048	512	256	1024
					Protection is (μ s) at interval	～246	～62	～31	～123
Ultimate range between transmitter (km)	90	22.5	11.25	45

Summary of the invention

In order to overcome the defective of existing scheme, merge the advantage separately of dual mode, the present invention proposes the implementation method of a kind of high-speed multimedia broadcast technique under a kind of CDMA2000 system in conjunction with the T-MMB system of Beijing new coastline company independent research.The invention provides a kind of real-time multimedia broadcast technology scheme, this scheme can provide high-quality video frequency program, support single frequency network, and can cover facility with the shared cover of CDMA2000 mobile network, and radio network and mobile network coexist with frequency range.

The technical solution adopted for the present invention to solve the technical problems is:

A kind of implementation method of high-speed multimedia broadcast technique under the CDMA2000 system, it is characterized in that: in the wireless access network of CDMA2000, set up and be exclusively used in the radio network that the real-time multimedia broadcasting service is provided, described radio network adopts macrocellular single-frequency broadcast transmission scheme, with utilize proprietary carrier frequency to realize that the single-frequency universe covers, promptly the broadcast transmitter of all cellular cells uses identical operating frequency in the big or small arbitrarily area of coverage, launches identical information.

Portable terminal is under the broadcasting pattern, and portable terminal resides at the cellular cell of radio network, can realize continuous receiving broadcast service program when mobile between all cellular cells and need not the sub-district and switch in radio network.

Described radio network adopts the OFDM modulation technique, and the waveform of broadcast singal designs with reference to the CDMA2000 signal waveform, and the operating frequency of radio network is used the working frequency range of CDMA2000.

Described broadcast system can be the broadcasting scheme that the broadcast system that uses the OFDM technology in the existing broadcast band is transformed.

The broadcasting scheme of being transformed, broadcast singal can transmit in the CDMA2000 communication bandwidth, and the broadcast transmitted pattern is applicable to the CDMA2000 working frequency range, and its radio-frequency front-end can be supported the CDMA2000 working frequency range.

The broadcasting scheme of being transformed is further characterized in that, if select T-MMB, DAB, standard technology such as T-DMB, DAB-IP to transform, changes the channel width of system, only need reselect the transmission mode when using the CDMA2000 frequency range.

Described a kind of method that real-time multimedia broadcasting is provided in the CDMA2000 mobile communications network comprises that further described broadcast system adopts the downstream frequency of CDMA2000, and coexists with frequency range with downstream frequency that CDMA2000 uses.

A kind of implementation method of high-speed multimedia broadcast technique also further comprises under the described CDMA2000 system, and the downstream frequency that described radio network and CDMA2000 mobile network use is with frequency range cobasis station, equipment altogether.

A kind of implementation method of high-speed multimedia broadcast technique under the described CDMA2000 system; also further comprise; the single-point broadcast transmitter adopts the small-power cellular basestation; the peak power output of described broadcast base station and stray radiation value will determine that its computational process may further comprise the steps according to technical indicators such as frequency protection band, space isolation between two systems

1) determines attainable space isolation on the engineering (station altogether);

2) determine minimum coupling loss (MCL) then;

3) determine transmitting power

4) receiver of the stray radiation=MCL+CDMA2000 base station interference level of agreing

A kind of implementation method of high-speed multimedia broadcast technique under the described CDMA2000 system comprises further that also radio network also is divided into a plurality of cellular cells, and all sub-districts all are divided into the same position district, promptly need not divide the lane place.

A kind of implementation method of high-speed multimedia broadcast technique under the described CDMA2000 system, also further comprise with regard to Electro Magnetic Compatibility and engineering construction, described radio network and mobile network can be shared indoor distributed system fully, and the coverage effect of former CDMA2000 mobile network indoor distributed system is not caused supplementary loss on any performance.

A kind of implementation method of high-speed multimedia broadcast technique under the described CDMA2000 system, the downstream frequency that also further comprises broadcast reception module and original receiver module in the described terminal is with terminal of frequency range coexistence.

A kind of implementation method of high-speed multimedia broadcast technique under the described CDMA2000 system, but also further comprise broadcast reception module and original receiver module common antenna in the described terminal.

The present invention is by being provided with professional radio network in existing C DMA2000 network, this radio network adopts special carrier frequency and OFDM modulation technique, supports the high-speed multimedia broadcasting service; The transmitter of all cellular cells adopts identical frequency in the radio network of the present invention, launches identical information, realizes that promptly the single-frequency universe covers, and need not divide the lane place; When the present invention used special carrier frequency to realize that the single-frequency universe covers, portable terminal need not switch the sub-district when mobile between all cellular cells of radio network; Broadcast system of the present invention and communication system down link frequency are coexisting with frequency range, and can stand, be total to compartment system in equipment, the coenecium altogether; But the downstream frequency of broadcast reception module and original receiver module is coexisting and common antenna with frequency range in the terminal of the present invention.

A kind of implementation method of high-speed multimedia broadcast technique under the CDMA2000 system of the present invention, compare with present technology and to have following advantage:

Radio network and mobile network shared network cover facility, have avoided overlapping investment, have reduced the cost of networking;

The 3G multi-media broadcasting service that can provide the two-forty universe to cover in the 5MHz bandwidth, can provide 12 cover high-quality video program (information source speed: 384kbps, frame per second: 25～30 frame/seconds) at least under the high-speed mobile environment;

Realize that macrocellular single-frequency universe covers, all television broadcastings only need a frequency, can receive continuously and need not to switch;

Macrocellular single-frequency broadcast transmission has reduced transmitting power effectively, has improved electromagnetic environment, " evenly " the covering field intensity, improved the rating quality, eliminated monkey chatter effectively, reduced electromagnetic pollution, to the protection environment favourable;

The networking of macrocellular single-frequency universe helps frequency planning, improves the availability of frequency spectrum, under the frequency spectrum resource condition of limited, and the frequency resource of saves valuable greatly.

Description of drawings

Fig. 1 T-MMB transmitting terminal theory diagram

Fig. 2 is network architecture figure of the present invention.

Fig. 3 is a cell structure schematic diagram of the present invention.

Fig. 4 is the network design figure of multimedia broadcasting net of the present invention.

Fig. 5 is a single frequency network structure chart of the present invention.

Fig. 6 is that single-frequency universe of the present invention covers the contrast schematic diagram that covers with general high-power single frequency network.

Fig. 7 is that co-channel interference is analyzed schematic diagram.

Fig. 8 is the frequency configuration schematic diagram of high power broadcast net and the independent networking of CDMA2000 mobile radio communication.

Fig. 9 is radio network of the present invention and the CDMA2000 communication network frequency configuration schematic diagram with band networking.

Figure 10 is the spatial separation schematic diagram of standing altogether and build in CDMA2000 base station of mobile communication network and T-MMB radio network base station.

Figure 11 is a shared indoor distributed system schematic diagram of the present invention.

Figure 12 is the structural representation that T-MMB receiver and CDMA2000UE coexist as same terminal.

Figure 13 is the single antenna schematic structure diagram.

Embodiment

For making purpose of the present invention, technical scheme and advantage clearer, theory analysis of the present invention and specific embodiment are described in detail below in conjunction with accompanying drawing.

The invention process at first will be selected and transform by the broadcast system (as technology such as T-MMB, DVB-H, T-DMB) of use OFDM technology in to existing broadcast band.If utilize the working frequency points of CDMA2000 system and the signal of bandwidth for transmission radio network, then require selected broadcast system to satisfy following two conditions:

1) the radio network signal can transmit in the 1.25MHz bandwidth;

2) the broadcast transmitted pattern need be supported the CDMA2000 working frequency range;

As select DVB-H standard (this standard adopts coherent demodulation system and its transmission mode only at the design of UHF wave band); for reaching above-mentioned purpose; just need series of parameters transformations such as reference symbol, and will carry out emulation and test again frame structure, sub-carrier number, protection interval, subcarrier spacing, synchro system.

As select the T-MMB standard, T-MMB system characteristics have determined the T-MMB broadcasting scheme only need simply transform, and just can satisfy above-mentioned two primary conditions.T-MMB system characteristics are as follows:

(30MHz～3000MHz) comprises the CDMA2000 frequency range to the frequency range that the T-MMB system supports;

The T-MMB system has multiple transmission mode can support different frequency spectrum and bandwidths.

In existing T-MMB broadcasting scheme, during the occupied bandwidth 1.536MHz of system, when the CDMA2000 frequency range is used, should select the transmission mode formula III.CDMA2000 channel width is 0.81 times that 1.25MHz is about the T-MMB bandwidth, the subcarrier number of transmission mode formula III is 192 in the T-MMB system, carrier spacing 8kHz, can selecting wherein, the parton carrier wave carries out transfer of data, such as adopting 156 subcarriers (signal bandwidth is about 156*8kHz=1.248MHz) to transmit, can keep subcarrier spacing constant and can in the 1.25MHz of CDMA2000 bandwidth, transmit like this.That is to say, change the channel width of T-MMB system, only need reselect the subcarrier number and just can in the CDMA2000 frequency range, use.

The working frequency range that existing T-MMB broadcasting scheme is supported at present is the high-power transmitter of Band III and L-Band, and enforcement of the present invention only needs the radio-frequency front-end of T-MMB system is transformed.Comprise that radio-frequency head increases corresponding mixting circuit to support the CDMA2000 working frequency range; Reduce the T-MMB transmitting power, adopt low power transmitter with the interference between the minimizing system etc.These are transformed all mature technique at present

In below implementing, the professional multimedia broadcasting net of setting up in the CDMA2000 communication system is based on the T-MMB technology.

Fig. 2 is a network system pie graph of the present invention.

Comprise T-MMB radio network, CDMA2000 mobile radio communication, content supplier, operation platform, ISP, portable terminal etc. among Fig. 2.Wherein the T-MMB radio network comprises assembly signal multiplexer and T-MMB radio network base station, and the CDMA2000 mobile radio communication comprises core net and CDMA2000 communication network base station.

The function of assembly signal multiplexer comprises following aspect in the T-MMB radio network: at first the audio frequency and video business information that provides according to content supplier is encoded, and generates multiplexing configuration information and business control information.Then the data of one or more audio frequency, video and data service are generated the assembly signal according to the form of message-source adapted.Form according to the assembly signal transmission interface sends to the T-MMB cellular basestation at last, and the T-MMB cellular basestation finally sends to the user to these contents.

The T-MMB system is transparent for information source transmission, supports multiple audio/video encoding/decoding form, such as AVS, MPEG4, H.264 wait.

The network platform of existing C DMA2000 communication network does not need to change, and the CDMA2000 communication network keeps the function of original business simultaneously also as CDMA2000 radio network up link, for mobile phone users provides interactive service.

Fig. 3 is a cell structure schematic diagram of the present invention.

Among Fig. 3, the network configuration of CDMA2000 mobile radio communication, (f1～f4), scrambler, base station location etc. remain unchanged before and after setting up radio network, protect original network investment to greatest extent to comprise carrier frequency.

The T-MMB radio network utilizes the proprietary carrier frequency f5 of CDMA2000 to broadcast, and radio network also is divided into a plurality of cellular cells.Because all sub-districts of radio network are used same frequency, sent identical information, promptly the single-frequency universe covers, so all sub-districts of radio network can be divided into the same position district, promptly need not upgrade the position.

Fig. 4 is the network design figure of multimedia broadcasting net of the present invention.

The multimedia broadcasting net is based on the T-MMB technology among Fig. 4.Because radio network is not subjected to the restriction of up link and capacity, the broadcast base station coverage is more much bigger than the coverage of CDMA2000 base station.Each little hexagon is the coverage of a CDMA2000 base station among Fig. 4, and typical covering radius is generally 700～800 meters.Each big hexagon is the coverage of a T-MMB broadcast base station.According to the theoretical analysis result of table 2, can see that the covering radius of T-MMB broadcast base station is at least four times of the covering radiuss of CDMA2000 base station, that is to say that each broadcast base station coverage correspondence the coverage of at least 16 CDMA2000 base stations.Each broadcast base station is stood altogether with the CDMA2000 base station that is positioned at its broadcast area center among Fig. 4, shown in dash area among Fig. 4.The all broadcast base stations of radio network adopt the proprietary carrier frequency f5 of CDMA2000 to broadcast and send identical information as shown in Figure 4.Therefore, under broadcast mode, portable terminal need not carry out the sub-district and switch as shown in Figure 4 when moving in all minizones of radio network.

Table 2 T-MMB link budget table

Fig. 5 is a single frequency network structure chart of the present invention.

The single frequency network that this programme is mentioned means in a certain geographic area on a large scale, adopts the small-power base station, simultaneously, with frequently, the same signal of emission, to realize reliable covering to this zone.Therefrom single frequency network SFN mainly comprises following content as can be seen:

A) assembly signal multiplexer (comprising the SFN adapter)

The assembly signal multiplexer can obtain business datum and business information simultaneously from one or more STIs, and then timestamp, logical frame sequence number, business datum and the fast information channel in dab receiver data encapsulation that generates according to business information are become logical frame.Wherein timestamp is the relative time deviant, the difference of pulse per second (PPS) (1PPS) reference time that the zero-time of this first bit of logical frame of expression transmission provides with respect to GPS.

B) emission (TX)/reception (RX) network adapter

Be used to provide from the center to the transparent link of each local unit.

C) synchro system

Synchro system provides the propagation delay time offset by the timestamp and local zone time (receiving the time of first bit) reference of relatively SFN adapter insertion, calculates the synchronous needed additional delay of SFN.

Single frequency network SFN adapter partly is the module relevant with the SFN function with synchro system, and this part function both can realize in independent equipment, also can be incorporated into flexibly in assembly signal multiplexer or the transmitter and realize.

D) T-MMB cellular basestation

The T-MMB cellular basestation need guarantee have one to determine to postpone between the air interface from being input to.In logical frame, insert corresponding information, be used to control each transmitter parameter.Because it is identical that SFN need guarantee the input bit of each transmitter, transmission signals, must keep synchronously so be in the clock of the transmitter of different location.Synchronizing information is provided by GPS

E) global positioning system (GPS)

Gps system is made of 24 navigation satellites that operate in apart from ground 20183km place, be distributed on 6 orbital planes that are mutually 60 degree angles, and accurate atomic clock is housed on the star.The GPS receiver can provide 10MHz frequency reference and a pulse per second (PPS) (1pps) timing reference signal simultaneously, uses synchronously for SFN.

Frequency Synchronization is realized by GPS that mainly the stability of general GPS reference clock can reach 10 ^-12Magnitude; Frequency stability still can reach 10 in the losing lock 24 hours ^-10More than.GPS receiver in the network extracts the high steady reference frequency signal of 10MHz.By the reference frequency signal of 10MHz, transmitter can upconvert to the operating frequency that needs, and realizes Frequency Synchronization.

The logical frame signal that the assembly signal multiplexer produces among the figure is sent to and respectively launches website by distributing network (transmission medium is cable or optical fiber etc.), after channel coding, modulation, the power amplification, is gone out by aerial radiation again.Each road logical frame signal is through the different transmission links and the processing of each base station, and the propagation delay time that arrives each transmitting antenna is equal not to the utmost, is good coverage and the effect of guaranteeing SFN, respectively transmits and should satisfy strict time relationship.This can be by the porch of channel encoder, and the compensating circuit that joins delay is realized.

Fig. 6 is that the single-frequency universe of this invention covers and general high-power single frequency network covering contrast schematic diagram.

The single-frequency universe coverage mode that this invention is adopted is different with the single frequency network of general meaning.General high-power single frequency network has the coverage restriction; depend primarily on the protection interval of OFDM symbol; promptly surpassing protection delay time signal at interval can impact reception; zone outside this coverage needs other frequency establishment single frequency network to cover; shown in A part among the figure; since the protection interval determination of OFDM a single frequency network coverage as shown in Table 1, cover so exceed the single frequency network 2 (frequency f2) of the other frequency of zone 2 needs of the coverage of single frequency network 1 (frequency f1).

And the small-power single-frequency universe coverage mode that the present invention adopts only needs a frequency can realize the covering in any magnitude range zone, and single-frequency universe coverage mode promptly of the present invention does not have the restriction of scope, shown in B part among the figure.But, thereby save frequency resource with a frequency f1 and overlay area 1 and zone 2.Simultaneously, adopt single-frequency universe coverage mode of the present invention, in all cellular cells of radio network, can realize receiving continuously and need not the sub-district and switch.

Fig. 7 is that co-channel interference is analyzed schematic diagram.

Why the present invention can adopt the single-frequency universe to cover is because co-channel interference can be ignored, and provides the theory analysis process of co-channel interference below.

Use in the cellular cell geometry " bunch " notion of (integral body that neighbor cell is formed), bunch size characterize by the sub-district number K of forming bunch, K value is big more, uses apart from just big more again, correspondingly interference power will be more little.

Supposition size all is P for the transmitting power of each launching tower antenna in the single frequency network of K (be similar to bunch) is all identical among the figure _t, receive " Carrier interference ratio " in center cell place terminal so and should be:

$C/I=\frac{P_t{G}_c\left({\mathrm{\φ}}_{0m}\right){\mathrm{kv}}_0/d_{0m}^{\mathrm{\γ}}}{\underset{i}{\mathrm{\Σ}}{P}_t{G}_c\left({\mathrm{\φ}}_{\mathrm{im}}\right){\mathrm{kv}}_i/d_{\mathrm{im}}^{\mathrm{\γ}}}={\left[\underset{i}{\mathrm{\Σ}}\frac{G_c\left({\mathrm{\φ}}_{\mathrm{im}}\right)v_i}{G_c\left({\mathrm{\φ}}_{0m}\right)v_0}{\left(\frac{d_{\mathrm{im}}}{d_{0m}}\right)}^{\mathrm{\γ}}\right]}^{-1}$

The following formula molecule is the available power that receives, and denominator is represented the interference summation that receives, and what look sub-district emission outside the center cell at present all is to disturb.Here center cell is defined as " No. 0 sub-district ", produces the label i of the sub-district of disturbing〉0, and have:

G _c()=bs antenna gain;

φ _ImThe antenna main beam of=cell i and the angle of portable terminal;

The proportional constant of k=and propagation loss;

v _iThe probabilistic unit of=sign propagation loss intermediate value lognormal stochastic variable;

d _ImThe antenna of=expression cell i is to the distance of portable terminal;

The power exponent of γ=propagation loss.

From definition as can be known, d _0mThe radius R that is less than or equal to the sub-district _c, the distance between interfered cell and the portable terminal is at nD ± R _cWithin the scope, wherein D represents to use distance again.The representative value of the propagation power exponent of land mobile communication is between γ=2.7 and γ=4.Antenna gain can be obtained by following model:

G _c(φ)=and constant, omnidirectional antenna

With

Consider to be positioned at the signal of the portable terminal reception of center cell from the center cell base station.Same frequency might use in another base station that with distance is nD more simultaneously.Can think that co-channel interference at this moment is very little owing to the reason (building stops etc.) of propagation loss or others.It is that all potential interference sources use this frequency simultaneously that cochannel disturbs the worst situation.If this moment, travelling carriage also was the worst situation, i.e. d apart from its base station distance _0m=R _c, and for the interfered cell on n the ring, the base station of interference is d to the mean value of the distance of travelling carriage _Im≈ nD, the forward link carrier/interface ratio intermediate value under the worst case is so:

$C/I={[\underset{i}{\mathrm{\Σ}}\underset{\mathrm{ring}1}{\frac{G_c\left({\mathrm{\φ}}_{\mathrm{im}}\right)}{G_c\left({\mathrm{\φ}}_{0m}\right)}{\left(\frac{R_c}{D}\right)}^{\mathrm{\γ}}}+\underset{i}{\mathrm{\Σ}}\underset{\mathrm{ring}2}{\frac{G_c\left({\mathrm{\φ}}_{\mathrm{im}}\right)}{G_c\left({\mathrm{\φ}}_{0m}\right)}{\left(\frac{R_c}{2D}\right)}^{\mathrm{\γ}}}+\underset{i}{\mathrm{\Σ}}\underset{\mathrm{ring}3}{\frac{G_c\left({\mathrm{\φ}}_{\mathrm{im}}\right)}{G_c\left({\mathrm{\φ}}_{0m}\right)}{\left(\frac{R_c}{3D}\right)}^{\mathrm{\γ}}}+\·\·\·]}^{-1}$

$={\left(\frac{R_c}{D}\right)}^{\mathrm{\γ}}{[\underset{i}{\mathrm{\Σ}}\underset{\mathrm{ring}1}{\frac{G_c\left({\mathrm{\φ}}_{\mathrm{im}}\right)}{G_c\left({\mathrm{\φ}}_{0m}\right)}}+{\left(\frac{1}{2}\right)}^{\mathrm{\γ}}\underset{i}{\mathrm{\Σ}}\underset{\mathrm{ring}2}{\frac{G_c\left({\mathrm{\φ}}_{\mathrm{im}}\right)}{G_c\left({\mathrm{\φ}}_{0m}\right)}}+{\left(\frac{1}{3}\right)}^{\mathrm{\γ}}\underset{i}{\mathrm{\Σ}}\underset{\mathrm{ring}3}{\frac{G_c\left({\mathrm{\φ}}_{\mathrm{im}}\right)}{G_c\left({\mathrm{\φ}}_{0m}\right)}}+\·\·\·]}^{-1}$

Utilize $D/R_c=\sqrt{3K}$ With the omnidirectional antenna pattern, its carrier/interface ratio is:

$C/I={\left(3K\right)}^{\mathrm{\γ}/2}{[6+12\·{\left(\frac{1}{2}\right)}^{\mathrm{\γ}}+18\·{\left(\frac{1}{3}\right)}^{\mathrm{\γ}}+\·\·\·]}^{-1}$

$=\frac{{\left(3K\right)}^{\mathrm{\γ}/2}}{6}{[1+{\left(\frac{1}{2}\right)}^{\mathrm{\γ}-1}+{\left(\frac{1}{3}\right)}^{\mathrm{\γ}-1}+\·\·\·]}^{-1}$

$=\frac{{\left(3K\right)}^{\mathrm{\γ}/2}}{6\·\mathrm{\ζ}(\mathrm{\γ}-1)}$

ζ () is the zeta function in the formula, and its expression formula is:

$\mathrm{\ζ}(\mathrm{\γ}-1)=\underset{n=1}{\overset{\∞}{\mathrm{\Σ}}}\frac{1}{n^{\mathrm{\γ}-1}}=\left\{\begin{array}{cc}\∞,& \mathrm{\γ}=2\\ {\mathrm{\π}}^2/6=1.6449,& \mathrm{\γ}=3\\ 1.2021,& \mathrm{\γ}=4\\ {\mathrm{\π}}^4/90=1.0823,& \mathrm{\γ}=5\end{array}\right.$

Like this, cover the ideal model of realizing single frequency network for honeycomb, adopt omnidirectional antenna, suppose that propagation loss is free-space loss (γ=2), disturb number to increase along with disturbing ring so, and remedied path loss, disturbing to increase does not have scope yet.But in the most mobile communication system, propagate power exponent and be generally γ=4.Like this, for omnidirectional antenna, the intermediate value of the worst carrier/interface ratio of forward link is:

$C/I=\frac{{\left(3K\right)}^2}{6\·\mathrm{\ζ}\left(3\right)}=1.2478K^2=\left\{\begin{array}{c}11.23=10.5\mathrm{dB},K=3\\ 19.97=13.0\mathrm{dB},K=4\\ 61.14=17.9\mathrm{dB},K=7\\ 101.1=20.0\mathrm{dB},K=9\\ 179.7=22.5\mathrm{dB},K=12\end{array}\right.$

More than analyzing the sub-district of looking outside the center cell is interfered cell.In the T-MMB system, because each OFDM symbol all has protection at interval, the single frequency network mode networking of adopting honeycomb to cover like this, as long as the signal of peripheral cell emission dropped within the protection at interval when arriving the center cell receiving terminal, receiver is looked useful signal.Therefore, center cell The transmitting power of the used base station in the scope is available power, and this moment, carrier/interface ratio was:

$C/I=\frac{\underset{i=0}{\overset{u}{\mathrm{\Σ}}}{P}_t{G}_c\left({\mathrm{\φ}}_{\mathrm{im}}\right){\mathrm{kv}}_i/d_{\mathrm{im}}^{\mathrm{\γ}}}{\underset{i=u+1}{\mathrm{\Σ}}{P}_t{G}_c\left({\mathrm{\φ}}_{\mathrm{im}}\right){\mathrm{kv}}_t/d_{\mathrm{im}}^{\mathrm{\γ}}}$

Through abbreviation, and the center of housing estate of i ring apart from the distance of center cell than approximate with 2i, then carrier/interface ratio is:

$C/I=\frac{\underset{i=0}{\overset{u}{\mathrm{\Σ}}}1/d_{\mathrm{im}}^{\mathrm{\γ}}}{\underset{i=u+1}{\mathrm{\Σ}}1/d_{\mathrm{im}}^{\mathrm{\γ}}}=\frac{1/R_c^{\mathrm{\γ}}+\underset{i=1}{\overset{u}{\mathrm{\Σ}}}1/{\left(\mathrm{iD}\right)}^{\mathrm{\γ}}}{\underset{i=u+1}{\overset{\∞}{\mathrm{\Σ}}}1/{\left(\mathrm{iD}\right)}^{\mathrm{\γ}}}={\left(\frac{D}{R_c}\right)}^{\mathrm{\γ}}\frac{1}{\underset{i=u+1}{\overset{\∞}{\mathrm{\Σ}}}1/i^{\mathrm{\γ}}}+\frac{\underset{i=1}{\overset{u}{\mathrm{\Σ}}}1/i^{\mathrm{\γ}}}{\underset{i=u+1}{\overset{\∞}{\mathrm{\Σ}}}1/i^{\mathrm{\γ}}}$

$={\left(3K\right)}^{\frac{\mathrm{\γ}}{2}}\frac{1}{\underset{i=u+1}{\overset{\∞}{\mathrm{\Σ}}}1/i^{\mathrm{\γ}}}+\frac{\underset{i=1}{\overset{u}{\mathrm{\Σ}}}1/i^{\mathrm{\γ}}}{\underset{i=u+1}{\overset{\∞}{\mathrm{\Σ}}}1/i^{\mathrm{\γ}}}=\frac{{\left(3K\right)}^{\frac{\mathrm{\γ}}{2}}+\underset{i=1}{\overset{u}{\mathrm{\Σ}}}1/i^{\mathrm{\γ}}}{\underset{i=u+1}{\overset{\∞}{\mathrm{\Σ}}}1/i^{\mathrm{\γ}}}$

In native system, the K=1 value is a worst case, the γ=worst dissemination channel environment of 4 representatives.The computing formula of C/I shows, C/I is the monotone decreasing function of γ, and the minimum value that C/I is described appears at K=1 and γ=2.7 o'clock, and the C/I value of gained is the value of system under the most abominable situation under this environment, if this moment, C/I can meet the demands, the system that can guarantee meets the demands in other cases.

As coverage radius of cell R _cWhen getting 2km (transmitting power of corresponding T-MMB is 10 watts), for employing transmission mode formula III,

(broken circle cover part among Fig. 7), the carrier/interface ratio intermediate value of this moment is:

$C/I=\left\{\begin{array}{c}8.1506\×{10}^2=29\mathrm{dB},\mathrm{\γ}=4\\ 3.7070\×{10}^2=26\mathrm{dB},\mathrm{\γ}=3.5\\ 1.7067\×{10}^2=22\mathrm{dB},\mathrm{\γ}=3\\ 1.0798\×{10}^2=20\mathrm{dB},\mathrm{\γ}=2.7\end{array}\right.$

Can see that according to above analysis result when the T-MMB system adopted the transmission mode formula III, Datong District pairing number of rings of covering radius frequently was u=2, we calculate the C/I of system under the most abominable situation is 20dB.For the T-MMB system, require C/I to be about 14dB, promptly the useful signal field intensity should exceed co-channel interference signal 14dB, therefore, in macrocellular single frequency network scheme, co-channel interference can be ignored, be need not the regulation maximum covering radius of system, can realize that the single-frequency universe covers.

Fig. 8 is the frequency configuration schematic diagram of high power broadcast net and the independent networking of CDMA2000 mobile radio communication.

As can be seen from Figure 8, when high power broadcast net (more than several hectowatts of transmitting power) and CDMA2000 mobile radio communication carry out independent networking respectively, need the frequency protection band of 20MHz to disturb at least, cause great frequency resource waste with opposing.

Fig. 9 is radio network of the present invention and the CDMA2000 communication network frequency configuration schematic diagram with band networking.

The frequency of CDMA2000 system is divided into upstream frequency and downstream frequency, and for the interference between the minimizing system, the frequency that the T-MMB radio network uses adopts the downstream frequency of CDMA2000 system.As can be seen from Figure 9, T-MMB radio network signal can transmit in the 1.25MHz of CDMA2000 system bandwidth, and the T-MMB radio network adopts the high-end frequency of CDMA2000 band downlink.

CDMA2000 system and T-MMB coexistence of systems and common station, its key point are to determine stray radiation and the maximum transmission power of T-MMB base station in the CDMA2000 frequency range according to interference analysis, and the concrete analysis process is as follows.

Figure 10 is the spatial separation schematic diagram of CDMA2000 base station of mobile communication network and T-MMB radio network base station construction.

A kind of spacing isolation method of Project Realization when Figure 10 has provided the base station side coexistence of systems, wherein the antenna length of CDMA2000 mobile network base station is 2 meters, antenna gain 11dBi, the antenna length of T-MMB radio network base station is 2 meters, antenna gain 15dBi, as can be seen from the figure, two antenna levels are isolated 3 meters, 3.8 meters of vertical isolation.

The engineering experience formula of computer memory isolation:

DH(dB)＝22+20*log(dH/λ)

DV(dB)＝28+40*log(dV/λ)

Wherein, DH represents horizontal isolation;

DV represents the vertical isolation degree;

DH represents horizontal isolation distance;

DV represents the vertical isolation distance;

λ represents the electric wave wavelength.

Suppose system in the work of 2G frequency, bring above-mentioned formula into and can draw level isolation 48dB, vertical isolation 80dB, space attenuation Loss=128dB like this.

The minimum coupling loss MCL=Loss-G of system _Tx-G _RxG wherein _TxBe T-MMB bs antenna gain value 15dBi, G _RxBe the gain of CDMA2000 antenna for base station, value 11dBi.Can draw minimum coupling loss MCL=128-15-11=102dB.

In base station side, when T-MMB system and CDMA2000 coexistence of systems, T-MMB radio network base station mainly comprises for the interference of CDMA2000 base station of mobile communication network: adjacent interference frequently, clutter interference, Intermodulation Interference and barrage jamming etc.Because the T-MMB system works is at the band downlink of CDMA2000,,, then must meet the following conditions if the signal that send the T-MMB base station does not influence the reception of CDMA2000 base station so mainly be clutter interference for the CDMA2000 base station receiver:

P _tr(f _i)-MCL≤I _max(f _i)

Wherein, f _iIt is the frequency of research;

P _Tr(f _i) be that the T-MMB base station is in certain transmitting power scope, at the maximum spur radiation value of CDMA2000 uplink band generation;

MCL is the minimum coupling loss between the transmitter and receiver, value 102dB;

I _Max(f _i) be in frequency f _iGo up acceptable maximum interference level,, get and receive the end value of making an uproar-130dBm/1.2288MHz for the base station of CDMA2000.

Can obtain the T-MMB base station like this at the maximum spur interference value of CDMA2000 uplink band is-28dBm/1.2288MHz, promptly require the T-MMB base station to launch with certain power on the CDMA2000 band downlink, the stray radiation that falls into the CDMA2000 uplink band can not surpass-28dBm/1.2288MHz.In the actual Project Realization, transmitting power is less than 25 watt-hours, and the frequency range stray radiation value that system uses generally is lower than-62dBm/4kHz.So 10～20 watts of the transmitting power values of T-MMB are at the stray radiation value-62dBm/4kHz of CDMA2000 uplink band.

Figure 11 is a shared indoor distributed system schematic diagram of the present invention.

Among Figure 11, the blind area that the T-MMB radio network can shared CDMA2000 mobile radio communication covers and the resource of indoor covering, and good covering is provided, overcome employing broadcast technology in the traditional broadcast net the cost height of arranging net, be difficult to the defectives such as covering that provide good.As shown in Figure 11, can share the facilities such as main push-towing rope, antenna of indoor distributed system with CDMA2000 mobile communication covering system based on the CDMA2000 radio network of T-MMB technology.Need not any change for CDMA2000 mobile communication indoor covering system.For the T-MMB radio network, it is dried put from main push-towing rope be coupled into very the signal of small intensity (degree of coupling is-20～-30dB), the down going channel signal of handling former CDMA2000 mobile communication covering system can not produce any influence like this; Simultaneously at the dried output adjunction band pass filter of putting of T-MMB, to improve the rejection of T-MMB signal to the dried data feedback channel of putting of former CDMA2000 mobile communication covering system.On the down going channel direction, former TD-SCDMA covering system is dried to be put with dried the putting of T-MMB covering system and adopts the degree of coupling synthetic for the directional coupler of-3dB carries out signal, and the covering field intensity equivalence of former TD-SCDMA covering system has been reduced 3dB.Consider the affluence amount of the existing actual fan-out capability of direct amplification machine product,, replenish this 3dB that reduces and cover field intensity by regulating the dried following line output of putting of former TD-SCDMA covering system.

Figure 12 is the structural representation that T-MMB receiver and CDMA2000UE coexist as same terminal.

As shown in figure 12, CDMA2000UE is similar with the T-MMB receiver structure, and the front is made of reception antenna, radio frequency Tuner, intermediate-frequency circuit, A/D converter, baseband processor, application processor, audio frequency digital-to-analogue conversion, display, keyboard etc.The baseband processor of the two can be shared an application processor, and wherein the audio-video code stream of T-MMB is given audio frequency digital-to-analogue converter and display confession user appreciation the Voice ﹠ Video data respectively after passing through application processor processes.In order to prevent that CDMA2000UE from disturbing the reception of T-MMB at ascending time slot, can take to disturb solution, be included in the CDMA2000 radio-frequency front-end and load a band pass filter (shown in dash area among the figure), use independently reception antenna respectively, increase the distance of CDMA2000 and T-MMB working frequency points etc.

Figure 13 is the single antenna schematic structure diagram.

Because the receiving terminal of T-MMB and CDMA2000 belongs to same frequency range, so can receive antenna by a shared cover.Figure 13 has provided the single antenna reception programme when coexisting as same terminal.From the terminal applies angle, the T-MMB terminal need receive the mobile TV signal always.And during this period, mobile communication terminal may also will be communicated by letter, and receives, firing operation etc.In this case, if a shared antenna, then this antenna need be finished two kinds of functions:

A) receive the signal of mobile communication system and T-MMB system at synchronization;

B) receive the T-MMB system signal at synchronization emission mobile communication system signal.

To this, can utilize the circulator structure to realize above-mentioned functions.Circulator can be realized transmission duplex, utilizes the high Q value among the Diplexer, and two filters of the outer inhibition ability of high-band are separated the received signal of mobile communication system and the received signal of T-MMB system.

The above is preferred embodiment of the present invention only, is not to be used to limit protection scope of the present invention, all any modifications of being made within the spirit and principles in the present invention, is equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (12)

1.CDMA2000 a kind of implementation method of high-speed multimedia broadcast technique under the system is characterized in that:

In the wireless access network of CDMA2000, set up and be exclusively used in the radio network that the real-time multimedia broadcasting service is provided, described radio network adopts macrocellular single-frequency broadcast transmission scheme, with utilize proprietary carrier frequency to realize that the single-frequency universe covers, promptly the broadcast transmitter of all cellular cells uses identical operating frequency in the big or small arbitrarily area of coverage, launches identical information.

Portable terminal is under the broadcasting pattern, and portable terminal resides at the cellular cell of radio network, can realize continuous receiving broadcast service program when mobile between all cellular cells and need not the sub-district and switch in radio network.

2. a kind of implementation method of high-speed multimedia broadcast technique under the CDMA2000 system according to claim 1, it is further characterized in that described radio network adopts the OFDM modulation technique, the waveform of broadcast singal designs with reference to the CDMA2000 signal waveform, and the operating frequency of radio network is used the working frequency range of CDMA2000.

3. a kind of implementation method of high-speed multimedia broadcast technique under the CDMA2000 system according to claim 1, it is further characterized in that described broadcast system can be the broadcasting scheme that the broadcast system that uses the OFDM technology in the existing broadcast band is transformed.

4. according to the implementation method of a kind of high-speed multimedia broadcast technique under claim 1 and the 3 described CDMA2000 systems, the broadcasting scheme of being transformed, be further characterized in that, broadcast singal is adapted at transmission in the CDMA2000 communication bandwidth 1.25MHz, the broadcast transmitted pattern is applicable to the CDMA2000 working frequency range, and its radio-frequency front-end can be supported the CDMA2000 working frequency range.

5. according to the implementation method of a kind of high-speed multimedia broadcast technique under claim 1 and the 3 described CDMA2000 systems, the broadcasting scheme of being transformed, be further characterized in that, if selecting T-MMB, DAB, standard technology such as T-DMB, DAB-IP transforms, the channel width of change system only need be reselected transmission data subcarrier number in the OFDM symbol.

6. a kind of method that real-time multimedia broadcasting is provided in the CDMA2000 mobile communications network according to claim 1 is characterized in that, described broadcast system adopts the downstream frequency of CDMA2000 and coexists with frequency range with the downstream frequency of CDMA2000 system.

7. a kind of implementation method of high-speed multimedia broadcast technique under the CDMA2000 system according to claim 1, it is further characterized in that equipment is stood, is total to described radio network and CDMA2000 mobile network altogether.

8. according to the implementation method of a kind of high-speed multimedia broadcast technique under claim 1, the 5 and 6 described CDMA2000 systems; it is further characterized in that; the single-point broadcast transmitter adopts the small-power cellular basestation; the stray radiation of described broadcast base station and transmitting power will determine that its computational process may further comprise the steps according to technical indicators such as frequency protection band, radio-frequency radiation characteristic, space isolation between two systems

1) determines attainable space isolation on the engineering (station altogether);

2) determine minimum coupling loss (MCL) then;

3) interference level that stray radiation=the MCL+CDMA2000 base station receiver is allowed

9. a kind of implementation method of high-speed multimedia broadcast technique under the CDMA2000 system according to claim 1, it is further characterized in that radio network also is divided into a plurality of cellular cells, all sub-districts all are divided into the same position district, promptly need not upgrade the position.

10. a kind of implementation method of high-speed multimedia broadcast technique under the CDMA2000 system according to claim 1, it is further characterized in that with regard to Electro Magnetic Compatibility and engineering construction, described radio network and mobile network can be shared indoor distributed system fully, and the coverage effect of former CDMA2000 mobile network indoor distributed system is not caused supplementary loss on any performance.

11. a kind of implementation method of high-speed multimedia broadcast technique under the CDMA2000 system according to claim 1, the broadcast reception module of described terminal and the downstream frequency of original receiver module are in terminal of frequency range coexistence.

12. a kind of implementation method of high-speed multimedia broadcast technique under the CDMA2000 system according to claim 1, but broadcast reception module and original receiver module common antenna in the described terminal.

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