Radio transmission system and method, and transmitter apparatus and receiver apparatus used in the radio transmission system

Wireless transmission system and method, transmitter device and receiver device used by the wireless transmission system

The present invention relates to a wireless transmission system and method, in particular to a wireless transmission system and method that uses orthogonal frequency symbol division multiple methods to make the diffusion rate of the symbol series of information variable according to the cell environment and the propagation environment.

In addition, the present invention relates to a transmitting station device used in such a wireless transmission system.

Furthermore, the present invention relates to a receiving station device used in this kind of wireless transmission system.

The wireless access method of the 3rd generation mobile communication method (1MT-2000: International Mobile Telecommunication 2000) adopts the W (Wideband)-CDMA (Code Division Multiple Access) method. Using this W-CDMA wireless interface, the average BER in the 5MHz band is = 10^-6The following high-quality 2Mbps transmission can be experimentally clarified.

However, with the broadbandization of the wired Internet so far, it is necessary to achieve high-speed mobile Internet transmission and reception in the mobile phone environment of mobile communication. Especially under the link between wireless base station transmission and mobile station reception, the increase in data circulation can be predicted by the downloading of images from websites and various databases and large-capacity files, so it is suitable for asymmetrical communication and pulse transmission from top to bottom. The data packet transmission becomes necessary.

From this background, the wireless interface of IS-95 was used as the basis and specialized into data communication. The high-speed data packet transmission (High Data Rate) that realized the maximum information transmission speed of 2.4Mbps in the 1.25MHz band was proposed.^rdThe Generation Partnership Project) expands the W-CDMA wireless interface 5MHz tie to achieve a high-speed data packet transmission method (HSPDA: High Speed Down Link Packet Access) with a maximum information transmission speed of 10 Mbps. In these methods, the forward and reverse modulation is changed according to the channel status, and the so-called adaptive forward and reverse modulation technology is used to achieve an information transmission speed of more than 2Mbps when the channel condition is good.

Under IMT-2000, a mobile communication method (= 4th generation mobile communication method), higher information transmission speed (throughput), that is, considering the difference between the upper and lower connections of the current mobile phone system data transmission Symmetry, specifically, it is necessary to provide a mobile phone system with a maximum transmission speed of 100 Mbps or higher for downlink transmission and 20 Mbps or higher for uplink transmission in a wide area coverage. However, there is a limit to the increase in the speed of information transmission by means of the aforementioned expansion of the existing wireless interface (HDR and HSPDA), and it is difficult to achieve a maximum transmission of about 100 Mbps. For example, when W-CDMA (DS-CDMA basis) converts the divided wireless head bandwidth into an ultra-wide frequency band of about 50-100 MHz, the wide frequency band means that the chip speed is formed at a higher speed, and the resolution of the channel is improved. The signal power of each channel is small but very many channels. Therefore, multi-path interference (MPI: Multi-path The increase in interference) and the deterioration of channel estimation accuracy have eliminated the RAKE time spreading effect. As a result, the transmission power is increased in order to achieve the expected reception quality at the expected information transmission speed, and the connection capacity is therefore reduced. Therefore, the wireless transmission method based on DS-CDMA is not suitable for high-speed and large-capacity data packet transmission in a wide frequency band of 50-100MHz. In addition, the orthogonal frequency division multiple method of digital terrestrial broadcasting and wireless LAN is used. The so-called OFDM (OFDM: Orthogonal Frequency Division Multiplex) is sufficiently extended because the symbol period of each carrier becomes very small compared with the delay time of multiple channels. That is, the symbol rate is reduced, and the influence of MPI can be reduced by inserting a guard interval (Guard Interval) that is longer than the maximum delay time of the main multi-channel into each symbol. Therefore, compared with the wireless transmission method using the above-mentioned DS-CDMA, the characteristic degradation of MPI caused by the wideband can be suppressed to be smaller, and it is suitable for high-speed signal transmission in the frequency band above 50-100MHz.

However, in this OFDM, due to the same channel interference (Co-channel interference), it is impossible to use the same carrier frequency in adjacent cells, and it is necessary to repeat the frequency of the cell. Therefore, in the OFDM method, the frequency band range in each cell can be used to form the full frequency band range of the system into a frequency band range in which the cell frequency is repeatedly divided, thereby reducing the efficiency of frequency utilization. In this OFDM method, in order to achieve 1-cell frequency repetition, highly dynamic channel allocation (DCA: Dynamic Channel Allocation) is necessary, and control becomes very complicated. In addition, common control channels such as notification channels and paging channels, which are frequently transmitted by intracellular communicators, have repeatedly become necessary.

On the other hand, in OFCDM (Orthogonal Frequency and Code Division Multiplex) of multi-carrier CDMA based on multi-carrier transmission spreading signals on the frequency axis, in order to use most carriers, the symbol is reduced and the MPI is reduced. Influence. Compared with the wireless transmission method based on DS-CDMA, the large capacity can be realized. It is disclosed in Paper 1 (S.Abeta, et al., IEEE VTC2000-Spring, pp. 1918-1922) and Paper 2 (Xinbo, Sadayuki Abe) , Sawahashi, RCS-2000-136, October 2000). However, this OFCDM can increase the system capacity compared to OFDM in the multi-cell method like a mobile phone system, but in an independent cell system like a wireless LAN and an office environment, it cannot achieve large-capacity compared to OFDM without proliferation. The problem.

Therefore, the first subject of the present invention is to provide a wireless transmission system that uses OFCDM to change the diffusion rate of transmitted information and can cover a wide range of cells in a wide frequency band.

Furthermore, the second subject of the present invention is to provide a transmitting station device using the wireless transmission system.

Furthermore, the third subject of the present invention is to provide a receiving station device using the wireless transmission system.

The wireless transmission system of the present invention uses the orthogonal frequency and the division multiple transmission method to carry out the wireless transmission of the above-mentioned information when transmitting information wirelessly between the transmitting station and the receiving station. In the system, the signaling bureau includes a conversion method for parallel conversion of the information symbolized by the simultaneous transmission channel and a diffusion symbol series with a diffusion rate based on a changeable complex diffusion rate in at least one of the frequency direction and the time direction. A means of diffusing the series of parallelized symbols in one direction.

In such a wireless transmission system, using the same wireless transmission method, the so-called diffusion rate of the transmitter and the receiver can be operated by OFCDM or OFDM by changing the wireless parameters. In order to make the flexible use of the two methods of OFCDM and OFDM possible, it can provide high-capacity, high-capacity, and high-capacity, which can provide a frequency utilization efficiency (the number of communicators that can meet the desired reception quality per 1 cell) that does not depend on the structure of cells and the transmission environment. Realized wireless transceiver mode.

Furthermore, in the wireless transmission system of the present invention, the spreading means may spread the series of parallelized symbols with a series of spreading symbols set based on a variable complex spreading rate in both directions of frequency and time.

In the wireless transmission system of the present invention, the transmitting station includes the first diffusivity determining means for obtaining the transmission environment representing the state of the transmission path between the transmitting station and the receiving station, and setting the aforementioned diffusivity according to the transmission environment It is also possible.

In such a wireless transmission system, the transmission environment representing the state of the transmission path between the transmitting station and the receiving station is obtained, and the diffusion rate is changed according to the transmission environment. For example, if OFCDM is used to make a better transmission environment diffusion rate of 1 or more, if OFDM is used to make a better transmission environment, the diffusion rate of 1 is variable. As a result, with the wireless transmission system of the present invention, it is possible to select (switch) the transmission and reception method (OFCDM or OFDM method) suitable for the transmission environment.

In the transmission system of the present invention, the first diffusion rate determining means obtains the delay spread representing the transmission delay characteristic, and the delay spread may be used as the above-mentioned transmission environment.

In particular, multi-carrier methods like OFCDM and OFDM are greatly affected by the frequency selectivity in the delay spreading frequency band, which represents the delay of multiple channels. Therefore, although the reception characteristics are affected, if this wireless transmission system is used, However, it is possible to realize the OFCDM method that can adaptively set the diffusion rate of the delay diffusion of the transmission path affected by the reception characteristics.

In the wireless transmission system of the present invention, the transmitting station includes a second diffusivity determining means for setting a diffusivity based on an instruction from the outside.

In this kind of transmission system, the diffusion rate set by the transmitting station can be instructed based on the control information content contained in the control signal from the outside of the receiving station (such as mobile station) and the network.

In the wireless transmission system of the present invention, the second diffusivity determining means may set a diffusivity according to any one of the information indicating the cell structure included in the control information indicating the instruction from the outside or the information specifying the diffusivity.

In this type of wireless transmission system, the receiving station includes, for example, information for specifying the diffusion rate of the control information sent from the mobile station. The mobile station obtains the diffusion rate set by the sending station based on the transmission status (delay profile) of the next link. Because the information specifying the diffusion rate is sent to the sending station by the control information notification, the following link is the adaptive control of the diffusion rate of OFCDM It is possible.

In addition, the wireless transmission system of the present invention includes information showing the control information of the cellular environment sent from the website. The information of the cell environment here includes information for operating the signaling station in a multi-cell environment (mobile phone environment) or information for operating the signaling station in a single cell (enclosed space environment such as wireless LAN). Therefore, it is possible to change the diffusion rate based on this cell information, so as a result, the adaptive control of the diffusion rate of the connected OFCDM is realized.

In the wireless transmission system of the present invention, the receiving station includes separating the receiving signal received at the receiving station from at least one of each sub-carrier and each time axis symbol, and using the channel estimate and the inherent spreading symbol series to be in phase The integral is equivalent to a diffusion rate control receiving means of at least one of the number of sub-carriers and the time axis symbol based on the number of a diffusion rate set based on the changeable complex diffusion rate.

In this type of wireless transmission system, the receiving station uses the estimated channel value and the inherent diffusion symbol series to inversely diffuse at least one of the carrier and the time axis symbol in the same phase as the number of the indicated diffusion rate, which can be used as an OFCDM action , Can also be used as OFDM action.

In the wireless transmission system of the present invention, the receiving station includes separating the receiving signal received at the receiving station from both the sub-carrier and each time axis symbol, and integrates in-phase with the estimated channel value and the inherent spreading symbol series. A diffusivity control receiving means equivalent to the number of sub-carriers and the time axis symbol based on the number of a diffusivity set based on the changeable complex diffusivity can also be used.

Furthermore, in the wireless transmission system of the present invention, the diffusion rate control receiving means may include a diffusion rate determining means that sets a diffusion rate based on a control signal included in a transmission station that becomes a communication partner.

In this kind of wireless transmission system, the receiving station can control the diffusion rate based on the control information notified from the receiving station that becomes the communication counterparty.

In the transmission system of the present invention, the diffusion rate determining means may set a diffusion rate according to any one of the information indicating the cell structure or the information indicating the diffusion rate included in the control signal from the transmitting station.

In this type of wireless transmission system, the receiving station changes the diffusion rate based on system information notified from the receiving station, such as information indicating the cell environment or information indicating the diffusion rate.

When the information notified from the originating station is the information of the specified diffusion rate, in this case, at the originating station (e.g., base station), because the system information is managed, it follows the multi-cell mobile phone system or independent cell (e.g., house) In-office environment), using cellular environment intelligence as an action platform for controlling information communication, and setting a diffusion rate suitable for each cellular environment.

When the information notified from the transmitting station is the information of the specified diffusion rate, in this case, the specified information of the diffusion rate determined according to the transmission status (delay profile, etc.) of the link on the transmitting station is used as the action machine to control the information communication. , Set the diffusion rate suitable for the transmission environment.

According to the above (1) and (2), there can be seamless connection between the cell environment different from the device with one wireless interface. As a result, it becomes possible to provide high-speed information transmission services in different cell environments for users, which can greatly improve the convenience for users.

In the wireless transmission method of the present invention, when transmitting information wirelessly between a transmitting station and a receiving station, it uses a multiple transmission method of focusing frequency and symbol division to transmit the same information by multiple carriers in parallel to carry out the wireless transmission of the above information. In the wireless transmission method, the conversion method of the transmitting station includes the steps of parallel conversion of the symbols of the information symbolized by the simultaneous transmission channel and the spreading method of the transmitting station. The series of the parallelized symbols is set based on the changeable plural diffusion rate. A step in which the diffusion symbol series of a diffusion rate is diffused in at least one of the frequency direction and the time direction.

In the wireless transmission method of the present invention, the first diffusion rate determining means of the transmitting station includes obtaining the transmission environment representing the state of the transmission path between the transmitting station and the receiving station, and setting the aforementioned diffusion rate according to the transmission environment Steps are also possible.

In the wireless transmission method of the present invention, the first diffusion rate determining means obtains the delay spread representing the transmission delay characteristic, and this delay spread may be used as the aforementioned transmission environment.

In the transmission method of the present invention, the second diffusivity determining means of the transmitting station may include a step of setting the aforementioned diffusivity based on an instruction from the outside.

In the wireless transmission method of the present invention, the second diffusivity determining means may set the aforementioned diffusivity according to any one of the information indicating the cell structure included in the control information indicating the instruction from the outside or the information indicating the specified diffusivity.

In the wireless transmission method of the present invention, the diffusion rate control receiving means of the receiving station includes separating the receiving signal received at the receiving station from at least one of each sub-carrier and each time axis symbol, and using the channel estimation value The in-phase integration with the inherent diffusion symbol series is equivalent to the step of changing at least one of the second carrier and the time axis symbol based on the number of a diffusion rate set by the complex diffusion rate.

In the wireless transmission method of the present invention, the diffusion rate control receiving means of the receiving station includes separating the receiving signal received at the receiving station from both sub-carriers and each time axis symbol, and using channel estimation values and inherent The in-phase integration of the diffusion symbol series is equivalent to the step of both the secondary carrier and the time axis symbol based on the number of a diffusion rate set by the changeable complex diffusion rate.

In the transmission method of the present invention, the determination means of the diffusion rate control reception means may include a step of setting a diffusion rate based on the control information included in the control signal transmitted from the receiving station that becomes the communication partner.

In the wireless transmission method of the present invention, the diffusion rate determining means may set a diffusion rate according to any one of the information indicating the cell structure of the control signal included in the transmitting station or the information specifying the diffusion rate.

The transmitting station device of the present invention uses the orthogonal frequency and symbol division multiple transmission method of transmitting the same information by multiple carriers in parallel to transmit information wirelessly with the receiving station device, including simultaneous transmission The conversion method of the symbol of the channel symbolized information parallel conversion and the diffusion method of spreading in at least one of the frequency direction and the time direction with a series of diffusion symbols set based on a variable diffusion ratio.

In the transmitting station device of the present invention, the spreading means is based on the conversion means of parallel conversion of the symbols of the information symbolized by the simultaneous transmission channel and spreads in the frequency with a series of spreading symbols set based on a variable spreading rate. Both direction and time direction are also acceptable.

In addition, the transmitting station device of the present invention may include the first diffusivity determining means for obtaining the transmission environment representing the transmission path between the transmitting station and the receiving station, and setting the aforementioned diffusivity according to the transmission environment.

Furthermore, in the transmitting station device of the present invention, the first diffusion rate determining means obtains the delay spread representing the transmission delay characteristic, and the delay spread may be used as the aforementioned transmission environment.

In addition, the transmitting station device of the present invention may include a second diffusivity determining means for setting a diffusivity based on an instruction from the outside.

In addition, in the signaling device of the present invention, the second diffusion rate determining means may set a diffusion rate in accordance with any one of the information indicating the cell structure included in the control information indicating the instruction from the outside or the information specifying the diffusion rate.

The receiving station device of the present invention is a receiving station device that receives signals wirelessly transmitted by the sending station device using the orthogonal frequency and symbol division multiple transmission method, including separating the receiving signal received at the receiving station from each carrier With at least one of the time axis symbols, using the channel estimation value and the inherent spreading symbol series will be equivalent to the number of sub-carriers and the time axis symbols set based on the variable complex diffusion rate. The diffusion rate control means of reception.

In the receiving station device of the present invention, the diffusion rate control receiving means separates the receiving signal received at the receiving office from both the sub-carriers and the time axis symbols, and uses the channel estimated value and the inherent diffusion symbol series to separate The number of sub-carriers and the time axis symbol corresponding to the number of a diffusion rate set based on the changeable complex diffusion rate may also be integrated in the same phase.

In the receiving station device of the present invention, the diffusion rate control receiving means may include a diffusion rate determining means for setting a diffusion rate based on the control information included in the control signal transmitted from the receiving station that becomes the communication partner.

In the receiving station device of the present invention, the diffusion rate determining means may set a diffusion rate according to either the information showing the cell structure included in the control signal from the receiving station or the information specifying the diffusion rate.

Furthermore, according to the various embodiments of the present invention, it will be fully understood with the following detailed description and accompanying drawings. These embodiments are only disclosed as examples, and are not used to limit the present invention.

In addition, the scope of application of the present invention will naturally become clear from the following detailed description. However, although the detailed description and specific examples disclose the preferred embodiments of the present invention, they are only disclosed as examples. The ideas of the present invention and the various changes and improvements of the invention should be more natural and clear from this detailed description. .

Hereinafter, the embodiments of the present invention will be described based on the drawings.

Fig. 1 is a diagram showing a wireless transmission system according to an embodiment of the present invention, such as an example of a mobile communication system. Figure 1 is an example of the structure of a field with a wireless network console, and Figure 2 is an example of the structure where the wireless network console is directly connected from the base station to the central network (IP network) without intervention.

In Figure 1, this mobile communication system is composed of a central network (CN) 100 and a wireless transceiver network (RAN) station 200. Furthermore, the RAN is composed of a wireless network console 201 and a plurality of base stations 202 and 203. The above-mentioned base stations 202 and 203 are grouped. The packet signal from the central network 100 is transmitted via the wireless network console 201 to the base station 203 connected to the mobile station 300 and the wireless connection.

The wireless network console has a combined (upper link)/distribution (lower link) mechanism for transmission. In the upper link, soft transfer is performed, and in the lower link, high-speed (low-speed) cell selection is performed. That is, in the above link, the packet channel sent from the mobile station is transmitted, and the multiple cells (base station) that are candidates for the software transmission are received, and the packet signal received at the base station is forwarded to the wired transmission path The wireless network console 201 is synthesized based on the reliability information.

On the other hand, in the link below, the same packet of signals is transmitted from the wireless network console 201 to the cell (base station) of the transmission candidate. From the base station of the soft transmission, the base station with the smallest open path loss difference with the mobile station is selected, and the selected base station sends the packet channel to the mobile station 300. When selecting the most suitable cell (base station), the base station is selected at the moment when the short period of time following the phase change is minimized with the path loss of the mobile station. The update method is high-speed cell selection, averaging the phase change, and choosing to accept static The update method of the base station with the smallest area change and distance change is low-speed cell selection. Regardless of the system, in order to reduce interference with other cells, the packet channel is sent from the cell (base station) with the smallest path difference. The transmission delay (delay profile) is different for each cell or block, so the base station The diffusion rate measured by the stations 202, 203 or the mobile station 300 is the basis for setting the diffusion rate.

Figure 2 shows the configuration of the base stations 202 and 203 directly connected to the packet gateway of the central network 100 without the wireless network console 201 (refer to Figure 1). In this structure, when the mobile station 300 is transmitting, the packet signal transmitted (forwarded) from the central network 100 is distributed (synthesized) in the cell (base station) of the transmission source. Furthermore, the transfer processing of the upper and lower links is performed in the same order as in Fig. 1.

The base stations 202 and 203 shown in Figures 1 and 2 (because the device structures of the base stations 202 and 203 are the same, so only "202" is given to the base station symbols below), for example, shown in Figure 3 structure.

In Figure 3, the base station 202 is composed of a low-noise amplifier unit 11, a signal amplifier unit 12, a wireless frequency distribution and synthesis unit 13, a wireless transceiver unit 14, a baseband signal processing unit 15, a wired transmission path interface unit 16, The control unit 17 and the antenna 18 are constituted.

Next, regarding the structure of the base station 202 shown in FIG. 1, an outline of the operation of the base station 202 will be described.

The packet data sent from the wireless network console 201 (the packet channel control unit of the central network) is received at the baseband signal processing unit 15 via the wired transmission path interface 16 and generated according to the diffusion set by the control unit 17. Rate of OFCDM signal. After the OFCDM signal is converted into analog In-Phase and Quadrature components by the D/A conversion mark of the wireless transceiver unit 14, it is converted into an intermediate frequency (IF) signal by a quadrature modulator. Converted to RF modulated signal. The converted RF modulated signal is synthesized by the radio frequency distribution and synthesis unit 13 and then transmitted through the antenna 18 amplified by the power amplifier 12.

On the other hand, the received signal received via the antenna 18 is amplified by the low-noise amplifier 11, is distributed by the wireless frequency distribution and synthesis unit 13, and is converted to an IF signal and quadrature detection in the wireless transceiver unit 14, and converted to The analogy is the in-phase and quadrature components. After that, the A/D converter in the baseband signal processing unit 15 converts it into a digital signal, and then reverses modulation and error correction decoding to regenerate the transmission packet data series. The regenerated packet data is transferred to the wireless network control unit 201 (the packet channel control unit of the central network) via the wired transmission path interface 16.

Although the diffusivity setting is completed in the aforementioned control unit 17, the diffusivity is set based on the delay spread measured by the wireless transceiver unit 14. For example, as shown in Figure 4, when the delay spread is large, a small frequency band range, that is, in a small carrier section, in order to increase the amplitude (phase) fluctuation, it is caused by the use of quadrature symbols to spread on the frequency axis. In this case, the orthogonality is disordered, and the interference between codes increases. Therefore, when the amplitude fluctuation is regarded as substantially constant, the carrier interval spreads. That is, the diffusivity is defined as the number of sub-carriers whose amplitude variation is regarded as a substantially constant frequency range. Generally, the size of delayed diffusion is set as τ, and the diffusion rate SF is set to the maximum diffusion rate in the range that satisfies the aforementioned relationship, so as to minimize the influence of interference by other cells. When the diffusion rate is small, most of the information symbols are in the range of the entire system, that is, mapping (frequency interleave) between all carriers. As the diffusion rate becomes larger, the information can be transformed between all carriers The number of symbols decreases. In short, not by diffusion rate, but by diffusion or frequency interleaving. In order to transform information and data in the whole carrier, sufficient frequency interleaving effect can be obtained. Therefore, with the base station according to the present invention, an OFCDM method can be realized in which the diffusion rate according to the delay spread of the transmission path can be set adaptively.

In the example of Fig. 4, although the spread in the frequency direction is staggered, as shown in Figs. 15 to 17, it is not necessary to spread the spread in the time direction. The example in Figure 15 shows the state of transmitting one information symbol with one OFCDM symbol (time axis symbol) and four secondary carriers. The example in Figure 16 shows the state of transmitting 1 information symbol with 4 OFCDM symbols and 1 secondary carrier. The example in Figure 17 shows the state of transmitting 2 information symbols with 1 OFCDM symbol (time axis symbol) and 2 secondary carriers. In the example of Figure 15 to Figure 17, the diffusivity of any one is 4.

In addition, the information of the diffusion rate set in the control unit 17 can be obtained from the wireless network console 201 of the upper station of the base station 202 or the central network 100.

Figure 5 is a diagram showing an example of the construction of the mobile station 300.

In Figure 5, this mobile station 300 is composed of an error detection (packet error detection) symbol adding section 21, a channel symbol section 22, an interleaving section 23, a data modulation processing section 24, a D/A conversion section 25, and a quadrature modulation section. 26. Up-conversion unit 27, power amplification unit 28, control unit 29, low-noise amplification unit 30, down-conversion unit 31, AGC amplification unit 32, quadrature detection unit 33, A/D conversion unit 34, inverse modulation processing unit 35 , A deinterleaving unit 36, a channel decoding unit 37, an error detection (packet error detection) unit 38, and an antenna 39.

Next, the outline of the operation of the mobile station 300 will be explained using this figure.

After the transmission packet data (transmission information data) is added with an error detection symbol (CRC symbol) to the error detection symbol adding section, the channel symbolizing section 22 is channel coded, and the interleaving section 23 is subjected to interleaving processing. After that, the symbolized data series are modulated by data in the data modulation processing unit 24, multiplexed with pilot bits and low-level control bits for channel estimation. In this way, the data-modulated in-phase and quadrature data series are converted into analog signals by the D/A conversion unit 25, and then quadrature modulated by the quadrature modulation unit 26. Therefore, the quadrature modulated signal is converted into an RF signal by the up-conversion unit 27, amplified by the power amplifier unit, and transmitted from the antenna 39.

As described above, it becomes the OFCDM signal that is transmitted by the diffusion rate set by the control unit 29 in accordance with the transmitted signal.

On the other hand, the OFCDM signal received via the antenna 39 is amplified by the low-noise amplifier 30, down-converted into an IF signal by the down-converter 31, linearly amplified by the AGC amplifier 32, and then quadrature-detected by the quadrature detector 33. The in-phase and quadrature signals of the quadrature detection are converted into digital data by the A/D conversion section 34, and then demodulated. After the demodulated signal is demodulated by the deinterleaving unit 36, the channel decoding unit 37 is error-corrected and decoded to reproduce the transmission packet data.

Figure 6 is a conceptual diagram showing the distribution of diffusion symbols of the variable diffusion rate OFCDM of the present invention. As shown in the figure, the double diffusion is achieved by the cell's inherent messy signal (1) and the orthogonal symbol (2) that identifies the code channel in the cell commonly used by each cell. The garbled code inherent in the cell is a code that cuts a very long period of code into a symbol of the length of several copies of the entire carrier. With orthogonal notation, Walsh notation can be used. The length of the orthogonal symbol, that is, the diffusion rate, is controlled by the cell environment and the transmission environment (delayed diffusion).

Figure 7 is a diagram showing an example of the structure of the pilot symbol for channel estimation.

As shown in the figure, the pilot symbols (1) at the head and the end of the packet are multiple times into a symbolized symbol series. The channel impulse response (estimated channel value) of the packet can be obtained by adding the FET output signals of all the pilot symbols at the head and the end of each carrier packet in phase. Especially when the delay spread is small, since the phase correlation between adjacent sub-carriers is very large, it can be obtained by further adding and averaging the channel estimation values of each sub-carrier estimated between several adjacent sub-carriers. Get higher precision channel estimation value.

Next, the theoretical analysis results of the connection capacity under the variable diffusivity OFCDM of the present invention are disclosed as follows.

The following (Math 2) shows the number of users per 1 cell that meets the expected reception quality when OFCDM and OFDM are used._OFCDMAnd N_OFDMThe approximate value of the relationship.

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N_OFCDM: The number of users per cell that meets the expected reception quality of OFCDM N_OFDM:The number of users per 1 cell meeting the expected reception quality of OFDM SF: Diffusion rate C_MUX:The code multiplicity of OFCDM that meets the expected quality η_OFCDM:Interference power ratio η of other cells to self-cell interference of OFCDM_OFDM:Interference power ratio of other cells to self-cell interference in OFDM F_OFCDM: OFCDM cell frequency repetition number F_OFDM: OFDM cell frequency repetition number S_OFCDM: The effect of OFCDM's blocking S_OFDM: If the effect of OFDM is divided by (Mathematical formula 2), OFCDM is SF copies of the same symbolized symbol series, bits, in order to be distributed into SF sub-carriers and transmitted with 1 code, although it is compared with OFDM The frequency utilization efficiency becomes 1/SF, but it can be multiplexed with C spread by different orthogonal symbols on the frequency axis_MUXA code channel. However, in the multi-channel phase (frequency selective phase) channel, the orthogonality between the code channels on the frequency axis collapses mainly due to the variation of the amplitude component between the carriers. Therefore, due to this inter-code interference, the number of multi-code channels that can meet the expected reception quality becomes a smaller value than SF. Therefore, in order to form

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For example, in the independent cell environment of wireless LAN (for example: IEEE802.11) (refer to Figure 8B), the number of users that can meet the expected reception quality of OFCDM, that is, the capacity, becomes smaller than that of OFDM. value.

On the other hand, in a multi-cell environment (refer to Figure 8A), OFCDM can use the same frequency band range in adjacent cells in order to spread in the frequency range with garbled symbols unique to each cell. In this regard, OFDM is caused by the interference of the same channel, and the same frequency band can be used in adjacent (adjacent) cells. When two antennas are used for divergence and reception, three-cell frequency repetition is necessary. Thus, in

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Therefore, even if the effect of blocking is not considered, the capacity of OFCDM's multi-cell mirror is larger than that of OFDM. Furthermore, in the case of considering blocking, OFCDM with the possibility of 1 cell frequency repetition has a greater effect on increasing the capacity of blocking compared to OFDM, and also has a greater effect on increasing the capacity of OFCDM of OFDM.

As mentioned above, it can be understood that OFCDM and OFDM are suitable for different cell environments. Therefore, if the transmission and reception method (either the OFCDM method or the OFDM method) that operates in accordance with the cellular environment is determined, the maximum high-speed information transmission speed can be achieved in an individual environment, and the capacity can be increased.

Specifically, by using a SF larger than 1 in a multi-cell environment such as a mobile phone system, it is possible to achieve 1 cell frequency repetition. In addition, by setting SF=1 in a single-cell environment such as wireless LAN, since the variable diffusion OFCDM is OFDMized, the frequency utilization efficiency can be improved.

In addition, in the past, if the cell environment is different, a device with a separate wireless interface is necessary. However, if the variable diffusion rate OFCDM is used, only the variable SF can match the different cell environment, so the cost of configuring the device can be reduced.

Figure 9 is a diagram showing an example of the structure of the transmitting baseband processing unit where the variable diffusivity OFCDM of the present invention is applied to the connection. The above-mentioned transmitting baseband processing unit is the baseband signal processing unit of the base station 2O2 shown in FIG. 3.

In Figure 9, the signal baseband processing unit is composed of a channel symbolizing unit 40, an interleaving unit 41, a multiplexing unit A42, a data modulation unit 43, a multiplexing unit B44, a serial/parallel conversion unit (S/P) 45, and a copy Section 46, Multiplication calculation section 47₁～47₁₁, An IFFT (Inverse Fast Fourier Transform) section 48, a Guard Interval insertion section 49, and a spreading symbol generation section 50.

Next, referring to Figures 9 and 18, the operation of the signal baseband processing unit will be described here. Figure 18 is a diagram showing the processing method in the signal baseband processing section.

First, the package detection symbolization is added to the package data (transmission information data), and the channel symbolization is performed by the channel symbolization unit 40 (error correction symbolization). After the information data of the channel symbolized by the channel symbolizing section 40 is subjected to the interleaving process of the time range in the interleaving section 41, the multiplexing section 42 and the control data are multiplexed. The symbolized data series multiplexed in the multiplexing section 42 are mapped in the data modulation section 43, and the pilot bit for channel estimation and the lower-level control information symbols are multiplexed in the multiple section B44. The multiplexed symbol data series are converted into parallel data of (the total number of carriers/diffusion rate) score in the serial/parallel (S/P) part of the serial/parallel (S/P) (step 01).

The designation of the diffusivity is performed by the diffusivity setting information from the control unit (step 02). The spreading rate is obtained by obtaining the delay spread that represents the transmission delay characteristics between the transmitting station and the receiving station, and it can also be set by the transmission environment obtained based on the delay spreading.

As the above-mentioned symbol data series converted by S/P, the same information symbol is copied into the continuous secondary carrier described in the diffusion rate (SF) in the copying unit 46 (step 03). At this time, copying to SF secondary carriers of the same symbol can realize the reciprocating reading of the symbol series input to the memory. The copying unit 46 may copy the same information symbol to consecutive OFCDM symbols (time axis symbols) described in the spread rate (SF). Moreover, it is also possible to combine the copying in the frequency direction and the time direction. After that, SF consecutive identical symbol series, the inherently allocated diffusion rate is diffused with the diffusion symbol of SF. Therefore, the spreading symbol series corresponding to the total number of sub-carriers is calculated by the inverse FFT (IFFT) in the IFFT section 48, and the time/frequency conversion of the multi-carrier components orthogonal on the frequency axis is performed. Finally, in the guard interval inserting part 49, the guard interval is inserted with the symbols of the multiple carriers. The insertion of this protection interval will be equivalent to the last N of each symbol_G1The signal waveform of each FFT sample is copied at the beginning of each symbol. The information of this processing forms the sending data (step 04).

Fig. 10 is a diagram showing an example of the structure of the receiving baseband processing unit where the variable diffusivity OFCDM of the present invention is applied to the next connection. The receiving baseband processing unit is also installed in the baseband signal processing unit of the base station 202 shown in FIG. 3.

As shown in the figure, the receiving baseband processing unit is composed of a guard interval removal unit 51, a symbol timing detection unit 52, a channel estimation unit 53, an FFT (fast Fourier transform) unit 54, and a multiplication calculator A group 55₁～55_n, Multiplication calculator B group 56₁～56_x, An in-phase addition calculation unit 57, a parallel/serial (P/S) conversion unit 58, a spread sign generation unit 59, a likelihood calculation unit 60, and an error correction decoding unit 61.

Next, referring to Figures 10 and 19, the operation of the receiving baseband processing unit will be described. Figure 19 is a diagram showing the processing method in the receiving baseband processing section.

The reception baseband processing unit receives reception data (step S11).

First, the symbol timing detector 52 detects symbol timing from the received multi-carrier signal (the timing for performing FFT calculation, also called FFT window timing). The detection of this symbol timing can be performed by the relevant detection of the interval of the guard interval. The guard interval removing unit 51 removes the signal of the guard interval from the symbol timing detected by the symbol timing detector 52 as described above. After that, the FFT section 54 performs calculations at the estimated FFT window timing to convert the multi-carrier signal into a series of parallel symbols. In the land mobile communication transmission of the mobile phone system, the received signal receives the multi-channel phase (frequency selective phase), so the channel estimation unit 53 uses the pilot symbols to estimate the channel impulse response (channel change) of each carrier (step S12) ). The in-phase addition calculation unit 57 adds the OFCDM symbols of the SF sub-carrier components in-phase on the frequency axis from the channel estimation value and the diffused overdispersion symbols of each sub-carrier used here, to generate an information symbol series (Step S13). In the in-phase addition calculation unit 57, in-phase addition (inverse diffusion) on the time axis may be used to generate the information symbol series, or in-phase addition on the frequency axis and on the time axis. The in-phase addition mode is set according to the diffusion mode of the sent information data. The inversely diffused (total carrier number/diffusion rate) information data symbols are P/S converted by the parallel/serial conversion unit, and after deinterleaving, the error correction decoding unit 61 performs error correction decoding. Therefore, the software determines the error correction and decoded information symbol series to regenerate the transmission information data (step S14).

Next, under the multi-cell environment of the structure shown in Fig. 1, the description of the transfer action for the occasion of using the variable diffusivity OFCDM of the present invention is linked.

If the mobile station within the range of the base station that transmits the root causes the radio link between the base station and the communication channel is completely established, the mobile station uses the control channel attached to the communication channel to notify the other partys cell. The inherent proliferation symbol of the cell. In addition, in all cells, the mobile station of the mobile station that is scheduled to be connected is the value of the diffusion rate (fixed value) of the common control channel of the wireless connection initially, and the mobile station can receive and transmit the common control channel of the other party's connection. Therefore, if the common control channel of the other cell is included here as the diffusion rate of the designated communication channel, it can indicate the diffusion rate of the communication channel of the mobile station. The aforementioned diffusion rate is determined at the base station that transmits the opponent's cell. Specifically, determine the most appropriate spread rate for the delay profile generated from the received signal from the communication channel connected on the mobile station.

As mentioned above, the mobile station indicates the diffusion rate from the base station that transmits the opponent's cell, so the mobile station uses the indicated diffusion rate to transmit and decode the communication channel connected under the opponent's cell.

Figure 11 is the simulation components used for the simulation evaluation of the capacity evaluation of the Kudzu variable diffusivity OFCDM of the present invention. This capacity evaluation is based on the average block error rate (BLER: Block Error Rate) of OFCDM.

As shown in the figure, the wireless bandwidth (Bandwidth) is 80MHZ, and the packet length is determined by N_p=4 OFCDM pilot symbol, N_d=60 constituted by OFCDM symbolized information symbols. Let the number of carriers N_e=512, SF=1(OFDM) and 32(OFCDM), 60(N_d)×512(N_e)=30,720 intelligence symbols, 60 (N_d)×512(N_e)/32(SF)=960 information symbol exists. Therefore, let 1 block of 960 intelligence symbols be used as capacity evaluation to compare the capacity of OFCDM and OFDM from the average BLER. Data Modulation/Spreading uses QPSK at the same time as the modulation method, Channel Coding/Decoding method (Channel Coding/Decoding) Symbolization rate (R) 1/2, and limit length (K) 9 rounds Convolutional coding, channel decoding is performed in Viterbi decoding of soft decision. In addition, the maximum Doppler frequency (Maximum Doppler frequency) is set to 80 Hz.

The interference of other cells in the multi-cell environment is in the case of OFCDM, the interference from the surrounding 6 cells of the own cell, and in the case of OFDM, the interference from the closest 6 cells using the same frequency is repeatedly considered as the 3 cell frequency. In addition, the signal from each cell is affected by the 4 law of distance attenuation, the standard deviation of the quiet zone system of 8dB, and the influence of the normal division and the multi-channel phase. The channel model of the multi-channel phase is shown in Figures 12A and 12B. The channel mode uses a 24-channel mode (delay spread σ=0.21μs) (refer to Figure 12A) and exponents from a channel group consisting of 8 channels with a triangular distribution of average receiving power. 18 modes of distribution (σ=0.29μs) (refer to Figure 12B).

First of all, in the variable diffusivity OFCDM, the capacity evaluation of the single-cell environment is presented in Document 2, so refer to Figure 13 for the capacity characteristics of the single-cell environment.

In a single-cell environment, the average BLER=10 to meet the requirement of changing multiple codes^-2Expected average letter E_b/N₀When comparing characteristics (non-antenna divergence reception), it meets the same expected average reception E as OFCDM (SF=1)_b/N₀In addition to the 24-channel mode, the multiplexed code number of OFDM (SF=32) can be achieved up to 32 codes. In the exponentially distributed 18-channel mode, it is 20 codes. As a result, the frequency utilization efficiency is lower than when SF=1. . This is due to the reduction of the divergence benefit caused by the reduction of the channel description and the increase of the influence of the collapse of the orthogonality on the frequency axis in order to increase the delay spread.

Figure 14 shows the simulation results of the average BLER characteristics when the variable diffusion rate OFCDM changes the multiplexing code in a multi-cell environment. As a prerequisite, the average reception E at the cell end_b/N₀Set it to 20dB, considering the antenna divergence and reception, and the transmission power control is not implemented.

As shown in the figure, although the average BLER when SF=1 (the number of multiplexed codes is 1) is 10^-1However, this is because the interference of the same channel from other cells becomes larger when the 3 cells reciprocate, and the characteristics become worse. From this figure, the number of multiplexed codes that meets the average BLER equal to SF=1 and SF=32 is about 16 codes (Figure 14-2).

Here, the capacity of each cell is η, and the information transmission when using the full wireless frequency band is R_b, The insertion loss of the guard interval and the leading symbol is β, the frequency reciprocation is F, and the number of multiple codes is K, which is defined as follows:

<maths><img file="TWI248317B_D0004.tif" /></maths>

Η when SF=1 (=the capacity of each cell of OFDM is η_OFDM)form

<maths><img file="TWI248317B_D0005.tif" /></maths>

When SF=32, the capacity of each cell of OFCDM is η_OFCDM)form

<maths><img file="TWI248317B_D0006.tif" /></maths>

As a result, OFCDM can ensure greater capacity than OFDM in a multi-cell environment. That is, the SF is made larger than 1 to realize the large capacity that can be achieved by 1 frequency reciprocation of OFCDM.

So far, if the variable diffusion rate OFDM with variable SF is used, in a multi-cell environment, SF&gt;1 and multiplying scatter codes on the frequency axis to achieve a large capacity of 1 cell frequency reciprocating, in a single cell environment, Make SF=1 can realize the high efficiency of frequency use efficiency.

In addition, by using the cell environment and the transmission environment as parameters that make the SF variable, the connection between different cell environments can be seamlessly connected with the same device structure. As a result, each cell environment can cover a wide range of cell coverage even without using a separate device.

In the above embodiment, the serial/parallel conversion unit 45 corresponds to the conversion means, the diffusion symbol generation unit 50 corresponds to the diffusion means, the delay diffusion acquisition function of the wireless transceiver unit 14 corresponds to the first diffusion rate determination means, and the external interface of the control unit 17 The function corresponds to the method of determining the diffusion rate. In addition, the control unit 29 of the mobile station 100 corresponds to the diffusivity control receiving means, and the external interface function of the control unit 29 corresponds to the diffusivity determination means.

In the above-mentioned embodiment, although the estimated transmission path changes at a certain moment are superimposed, the copied information symbols can be synthesized by the two-dimensional state of the copying means (Copier) on the frequency axis and the time axis. In this way, when multiple frequencies and time are used to overlap, it becomes possible to take out the received signal with higher accuracy with respect to the change in the time direction, that is, the phase change.

From the above description, it is obvious that the present invention can be modified in various ways. This kind of deformation should not be considered as going beyond the thought and scope of the present invention. It is self-evident to all those in the industry that it is included in the scope of the following patent applications.

Commercial availability

In the present invention, in the same wireless transmission and reception mode, the so-called diffusion rate of the transmitter and the receiver can be operated as OFCDM or OFDM by changing the wireless parameters. Therefore, in order to make the two methods of OFCDM and OFDM flexible to use separately, it can provide a large capacity with high frequency utilization efficiency (the number of communicators that can meet the expected reception quality per 1 cell) independent of the cell structure and transmission environment. Realizable wireless transceiver mode.

Therefore, by using OFCDM to make the spread rate of the transmitted information variable, it can provide a wireless transmission system that is possible for broadband packet transmission in a wide range of cell coverage.

<p>11. . . Low noise amplifier</p><p>12. . . Signaling and amplifying part</p><p>13. . . Radio Frequency Allocation and Synthesis Department</p><p>14. . . Wireless Transceiver Department</p><p>15. . . Fundamental Frequency Signal Processing Department</p><p>16. . . Wire transmission path interface</p><p>17. . . Control Department</p><p>18. . . antenna</p><p>twenty one. . . Error detection symbol additional part</p><p>twenty two. . . Channel Symbol Department</p><p>twenty three. . . Intersection</p><p>twenty four. . . Data Processing Department</p><p>25. . . D/A Conversion Department</p><p>26. . . Quadrature Modulation Section</p><p>27. . . Upconversion Department</p><p>28. . . Power Amplification Department</p><p>29. . . Control Department</p><p>30. . . Low noise amplifier</p><p>31. . . Down conversion</p><p>32. . . AGC Amplification Department</p><p>33. . . Quadrature detector</p><p>34. . . A/D conversion department</p><p>35. . . Anti-modulation processing section</p><p>36. . . Deinterlace</p><p>37. . . Channel Decoding Department</p><p>38. . . Error detection department</p><p>39. . . antenna</p><p>40. . . Channel Symbol Generation Department</p><p>41. . . Intersection</p><p>42. . . Multiple part A</p><p>43. . . Data Preparation Department</p><p>44. . . Multiple part B</p><p>45. . . Serial/Parallel Conversion Unit</p><p>46. . . Copy Department</p><p>47. . . Multiplication calculation department</p><p>48. . . IFFT Department</p><p>49. . . Guard zone insertion part</p><p>50. . . Diffusion Symbol Generator</p><p>51. . . Guard zone removal part</p><p>52. . . Symbol timing detection department</p><p>53. . . Channel estimation department</p><p>54. . . TFT Department</p><p>55. . . Multiplication calculator A group</p><p>56. . . Multiplication calculator B group</p><p>57. . . In-phase addition calculation unit</p><p>58. . . Parallel/serial conversion section</p><p>59. . . Diffusion Symbol Generator</p><p>60. . . Likelihood calculation department</p><p>61. . . Error Correction Decoding Department</p><p>100. . . Central network</p><p>200. . . Wireless transceiver network</p><p>201. . . Wireless transceiver console</p><p>202. . . Base station</p><p>203. . . Base station</p><p>300. . . Action station</p>

Fig. 1 is a diagram showing a configuration example (1 of them) of a mobile communication system according to an embodiment of the present invention.

Fig. 2 is a diagram showing a configuration example (2 of them) of a mobile communication system according to an embodiment of the present invention.

Figure 3 is a diagram showing an example of the structure of the base station according to the present invention.

Figure 4 is a diagram showing the spread and interleaving of the frequency range.

Figure 5 is a diagram showing an example of the structure of the mobile station according to the present invention.

Figure 6 is a conceptual diagram showing the diffusion symbol allocation method.

Figure 7 is a diagram showing an example of the structure of the pilot symbol for channel estimation.

Figure 8A is a diagram showing a multicellular environment.

Figure 8B is a diagram showing a single cell environment.

Fig. 9 is a diagram showing an example of the structure of the baseband processing section of the transmission baseband applicable to the case where the variable diffusion rate OFCDM of the present invention is connected underneath.

Fig. 10 is a diagram showing an example of the structure of the baseband processing section of the transmission baseband when the variable diffusion rate OFCDM of the present invention is connected underneath.

Figure 11 is a diagram showing simulation components used for the simulation evaluation of the capacity evaluation of the variable diffusivity OFCDM of the present invention.

Fig. 12A is a diagram showing an example of the channel mode shown in Fig. 11.

Fig. 12B is a diagram showing an example of the channel mode shown in Fig. 11.

Figure 13 is a diagram showing the capacity evaluation characteristics of a single-cell environment in the variable diffusivity OFCDM of the present invention.

Figure 14 is a diagram showing the capacity evaluation characteristics of a multicellular environment in the variable diffusivity OFCDM of the present invention.

Figure 15 is a diagram showing the spread and interleaving of frequency and time ranges.

Figure 16 is a diagram showing the spread and interleaving of frequency and time ranges.

Figure 17 is a diagram showing the spread and interleaving of frequency and time ranges.

Figure 18 is a diagram showing the processing method in the signal basic frequency band processing section.

Figure 19 is a diagram showing the processing method in the signal basic frequency band processing section.