WO2003085919A1

WO2003085919A1 - Adaptive modulation encoder for base station and mobile station

Info

Publication number: WO2003085919A1
Application number: PCT/JP2002/003461
Authority: WO
Inventors: Michiaki Takano
Original assignee: Mitsubishi Denki Kabushiki Kaisha
Priority date: 2002-04-05
Filing date: 2002-04-05
Publication date: 2003-10-16

Abstract

TFRCs (1) to (6) which an adaptive processor (26) refers to are set so that the step of Ior/Ioc characteristic is not larger than 2 dB Alternatively TFRCs (1) to (6) are set so that the step of Ior/Ioc characteristic is 1 dB. Since power offset need not be included in a down-link signaling, an overhead increase is prevented, and the link capacity is increased thereby.

Description

Description Adaptive modulation and coding equipment for base stations and mobile stations

The present invention relates to an adaptive modulation and coding device for a base station and a mobile station that constitute a communication system using a cellular system. Background art

An adaptive modulation and coding scheme is used in a cellular mobile communication system, especially in a high-speed packet communication system.

The adaptive modulation and coding method is, for example, a method in which a base station feedbacks the reception quality of a mobile station, and the base station adaptively switches a modulation method and a coding rate based on the reception quality of the mobile station. . The switching time interval is usually several ms (for example, 2 ms).

Fig. 1 shows, for example, “Nokia:“ UL signaling for TFRC selection ”, R l — 0 1 — 1 0 2 4, TSG—R AN WG 1 HSDPA adhocmeeting, Sophia Antipolis, France, November 5 ^th — 7 ^th , 2 ⁰⁰¹ , is a configuration diagram showing a conventional adaptive modulation and coding apparatus of a base station, wherein 1 is a transport block divider that divides transmission information into transport blocks. Reference numerals 2 and 2 denote encoding units that encode the transport blocks divided by the transport block divider 1.

3 is an interleaver that performs interleaving on the transport block encoded by the encoding processor 2, and 4 is an interleaver. A mapping device that converts the bit data, which is the output data of the bar 3, into symbol data, a spread modulator 5 that spreads and modulates the symbol data output from the mapping device 4, and 6 that is output from the spread modulator 5. A power offset unit that adds a power offset to the spread modulation signal. The reception quality of the mobile station is selected from among a plurality of preset TFRCs (Transport, Format, Resource, and Combination). TFRC is selected according to the TFRC, and adaptive processing for controlling the transport block divider 1, coding processor 2, mapping unit 4, spreading modulator 5, and power offset unit 6 according to the definition of the TFRC. It is a vessel.

Next, the operation will be described.

When the base station transmits transmission information to the mobile station, the transmission information is supplied to the transport block divider 1 from the upper layer.

When the transmission information is provided from the upper layer, the transport block divider 1 divides the transmission information into transport blocks. That is, the transmission information is divided so that the number of blocks of the transmission information matches the transport block size specified by the adaptive processor 7.

Upon receiving the transport block from the transport block divider 1, the encoding processor 2 encodes the transport block at the encoding rate specified by the adaptive processor 7. That is, the coding processor 2 performs coding processing for error correction, and also performs bit number adjustment for matching the number of bits of the transport block with the number of bits of the physical channel.

When the encoder 2 encodes the transport book, the interleaver 3 performs an interleave process on the transport block.

Interleave processing is performed for each channel. For example, when there is a memory having a row X column configuration, for example, data write processing to the memory is performed in the column direction, while data read processing is performed in the row direction. By performing the interleave processing, it is possible to mitigate the long-term continuation of the level decrease caused by Doppler specific to mobile communication.

When the interleaver 3 performs the interleaving process, the mapping device 4 converts the bit data, which is the output data of the interleaver 3, into symbol data. That is, data mapping is performed by the modulation method instructed by the adaptive processor 7. Here, it is assumed that a plurality of bit strings are converted into QPSK or 16QAM IQ symbols. Upon receiving the symbol data from the mapping unit 4, the spread modulator 5 performs spread modulation of the symbol data with the number of codes specified by the adaptive processor 7.

Upon receiving the spread modulation signal from spread modulator 5, power offsetter 6 adds a power offset indicated by adaptive processor 7 to the spread modulated signal. The reason for adding the power offset will be described later.

The spread modulated signal to which the power offset has been added is then subjected to radio frequency conversion / filtering processing and the like, and then transmitted from the antenna to the mobile station.

The transmission information of the base station is transmitted to the mobile station as described above, and the adaptive processor 7 adaptively switches the modulation scheme and the coding rate according to the reception quality of the mobile station.

That is, when the adaptive processor 7 receives the feed pack signal indicating the reception quality of the mobile station, the adaptive processor 7 refers to the feedback signal and selects an optimal T FRC from a plurality of T FRCs set in advance.

Then, referring to the definition of the TFRC, the transport block The size is output to the transport block divider 1, the encoding rate is output to the encoding processor 2, the modulation scheme is output to the mapper 4, and the number of codes is output to the spreading modulator 5. Also, it outputs the offset power to the power offset unit 6.

Here, FIG. 3 is an explanatory diagram showing the definition contents of T FRC set in advance. In the example of FIG. 3, six types of T FRCs are set, and T F R.C (1) to (6) define a modulation method, a transport block size, the number of codes, and a coding rate.

Fig. 4 is an explanatory diagram showing the steps of I or ZI oc (lor: total transmission power of the base station, I oc: interference power and noise power from other cells). For example, TFRC (1) Force, et al. TFRC (2) Step I

The characteristic difference of 0 rZIoc characteristic is 3.2 dB, and the characteristic difference of Ior / Ioc characteristic is 3.1 dB in the steps from TFRC (2) to TFRC (3).

The characteristic difference reaches 2 dB in each step.

Therefore, when the power offset unit 6 transmits the spread modulation signal without adding a power offset to the spread modulation signal, the mobile station on the receiving side transmits

Every time the T FRC is changed, the IorZloc characteristic of the received signal is greatly changed, and the reception quality is greatly degraded.

Therefore, in the conventional adaptive modulation and coding apparatus of the base station, the power offset unit 6 is provided after the spreading modulator 5 so that the step of the I or / I oc characteristic becomes about 1 dB. ing.

FIG. 5 is an explanatory diagram showing the block error rate characteristics of TFRC (1) to (6). In the example of FIG. 5, IorZ in which TFRC (1) is the smallest is shown.

Indicates that transmission is possible with 1 oc characteristics. In other words, it indicates that T FRC (1) can communicate with the lowest required channel quality.

For example, when the allowable value of the block error rate is BLER th, It is desirable to select TFRC (1) below threshold A, preferably TFRC (2) below threshold B, preferably TFRC (3) below threshold C, and TFRC below threshold D. It is desirable to select (4), TFRC (5) below threshold E, and TFRC (6) above threshold E.

Therefore, if the adaptive processor 7 can receive a threshold (the upper limit of the I or ZI oc characteristic) as a feedback signal from the mobile station, the adaptive processor 7 can select an optimal TFRC from a plurality of preset TFRCs. it can.

The base station notifies the mobile station of the transport block size, coding rate, modulation scheme and number of codes defined in the selected TFRC, power offset, and the like by downlink signaling.

FIG. 2 is a block diagram showing a receiving apparatus of a mobile station. In the figure, reference numeral 11 denotes a channelization code set CCS (Channelaization Code Set) included in downlink signaling. A despreader that recognizes the number of codes from the Nerization code number and despreads the spread modulation signal with that code number.12 is a demapper that converts the symbol data output from the despreader 11 into bit data. Reference numeral 13 denotes a dinter leaver that performs a dinterleaving process on the bit data output from the de-mapping device 12, and reference numeral 14 denotes a transport block which is bit data output from the deinterleaver 13. Decryption processor to decrypt, 15 is 〇 1 〇? 1 is a receiver, and 16 is a T FRC converter.

Next, the operation will be described.

When the mobile station antenna receives the spread modulation signal transmitted from the base station, the spread modulation signal is supplied to despreader 11 after radio frequency conversion is performed. . The despreader 11 recognizes the number of codes from the channelization code number provided by the channelization code set CCS included in the downlink signaling, and converts the spread modulation signal using the code number. Despreads and outputs symbol data.

However, when outputting the symbol data, the despreader 11 refers to the power offset included in the downlink signaling, removes the power offset from the symbol data, and outputs the result.

Upon receiving the symbol data from despreader 11, demapper 12 converts the symbol data into bit data in accordance with the modulation scheme included in the downlink signaling.

Upon receiving the bit data from the demapper 12, the interleaver 13 performs the interleave process on the bit data. Upon receiving the transport block, which is bit data, from the interleaver 13, the decoding processor 14 decodes the transport block according to the encoding rate included in the downlink signaling. Performs and outputs the transport block after decryption.

Since the conventional adaptive modulation and coding apparatus of the base station is configured as described above, even if the TFRC is changed, it is possible to suppress a large change in the I or / I oc characteristic. In addition, the power offset must be included, which has led to an increase in overhead.

In addition, if the power offset is included in the message without including the power offset in the downstream signaling, the overall increase in overhead can be suppressed. Since it is necessary to extract the power offset from the message, control delay is incurred, and a 2 ms change like TFRC cannot be expected, resulting in a problem of reduced link capacity.

Also, the downlink signaling does not include the power offset, and the mobile station side If a measuring instrument that detects the power offset is installed in the system, the increase in overhead can be prevented.However, the increase in the size of the measuring instrument leads to an increase in the size of the hardware and a new measurement process. The processing load imposes a problem of deteriorating the reception accuracy.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is an adaptive modulation and coding method for a base station and a mobile station that can increase the link capacity by preventing an increase in overhead. The aim is to obtain a device. DISCLOSURE OF THE INVENTION ''

The adaptive modulation and coding apparatus of the base station according to the present invention sets a plurality of TFRCs such that the step of the I or ZI oc characteristic is smaller than a predetermined value when setting the TFRC referred to by the adaptive processing means. is there.

This has the effect of preventing an increase in overhead and increasing the link capacity.

The adaptive modulation and coding apparatus of the base station according to the present invention, when given the upper limit of the I or ZI oc characteristic from the mobile station, is the most TFRC among the TFRCs whose I or ZI oc characteristic does not exceed the upper limit TFRC with a large or / loc characteristic is selected.

As a result, there is an effect that an optimal T FRC can be selected without complicating the configuration.

In the adaptive modulation and coding apparatus for a base station according to the present invention, a plurality of TFRCs are set such that the step of the Ior / Ioc characteristic is 1 dB.

This has the effect that large fluctuations in the Ior / Ioc characteristics can be suppressed.

An adaptive modulation and coding apparatus for a base station according to the present invention includes: This is a set of multiple TFRCs using repetitions.

As a result, there is an effect that variations in the transport block size can be reduced without reducing coding rate variations.

The adaptive modulation and coding apparatus of the mobile station according to the present invention sets a plurality of TFRCs so that the step of the I or / I oc characteristic becomes smaller than a predetermined value when setting the TFRC referred to by the adaptive processing means. Things.

The adaptive modulation and coding apparatus for a mobile station according to the present invention, when given an upper limit of the I or / I oc characteristic from the base station, is the most TFRC among the TFRCs whose I or Z loc characteristic does not exceed the upper limit. or TFRC with a large Z loc characteristic is selected.

In the adaptive modulation and coding apparatus for a mobile station according to the present invention, a plurality of TFRCs are set such that the step of the IorZloc characteristic is 1 dB.

An adaptive modulation and coding apparatus for a mobile station according to the present invention sets a plurality of T FRCs using a repetition of rate matching.

This has the effect of reducing the transport block size variation without reducing the coding rate variation. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a configuration diagram showing a conventional adaptive modulation and coding device of a base station. FIG. 2 is a configuration diagram showing a receiving device of a mobile station.

FIG. 3 is an explanatory diagram showing the contents of the predefined T FRC definition. FIG. 4 is an explanatory diagram showing the steps of the Ior Zloc characteristic.

FIG. 5 is an explanatory diagram showing the block error rate characteristics of TFRC (1) to (6).

FIG. 6 is a configuration diagram showing an adaptive modulation and coding apparatus for a base station according to Embodiment 1 of the present invention.

FIG. 7 is a configuration diagram showing a receiving device of a mobile station.

FIG. 8 is an explanatory diagram showing QPSK mapping.

FIG. 9 is an explanatory diagram showing the input / output relationship of the mapping device.

FIG. 10 is an explanatory diagram showing 16Q AM mapping.

FIG. 11 is an explanatory diagram showing the input / output relationship of the mubbing device.

FIG. 12 is an explanatory diagram showing the contents of the predefined T FRC definition.

FIG. 13 is an explanatory diagram showing steps of the Ior Zloc characteristic.

FIG. 14 is an explanatory diagram showing the block error rate characteristics of TFRC (1) to (6).

FIG. 15 is an explanatory diagram showing QPSK demapping.

FIG. 16 is an explanatory diagram showing the input / output relationship of the demapping device.

FIG. 17 is an explanatory diagram showing 16 QAM demapping.

FIG. 18 is an explanatory diagram showing the input / output relationship of the de-mugging device.

FIG. 19 is an explanatory diagram showing the pre-set TFRC definition contents. FIG. 20 is an explanatory diagram showing the contents of the TFRC definition that are set in advance.

FIG. 21 is an explanatory diagram showing steps of the Ior / Ioc characteristic.

FIG. 22 is an explanatory diagram showing the block error rate characteristics of TFRC (1) to (6).

FIG. 23 is an explanatory diagram showing the contents of the predefined T FRC definition.

FIG. 24 is an explanatory diagram showing the contents of the predefined T FRC definition.

FIG. 25 is an explanatory diagram showing the contents of the predefined T FRC definition.

FIG. 26 is an explanatory diagram showing the contents of the predefined T FRC definition.

FIG. 27 is an explanatory diagram showing the contents of the predefined T FRC definition. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, in order to explain this invention in greater detail, the preferred embodiments of the present invention will be described with reference to the accompanying drawings.

Embodiment 1.

FIG. 6 is a block diagram showing an adaptive modulation and coding apparatus for a base station according to Embodiment 1 of the present invention. In the figure, reference numeral 21 denotes a transport block divider (divider) for dividing transmission information into transport blocks. Means) and 22 are encoding processors (encoding means) for encoding the transport blocks divided by the transport block divider 21.

2 3 is the transport block encoded by the encoder 2 2 An interleaver 24 performs an interleave process on the input data, 24 is a mapping device (mapping means) that converts bit data, which is output data of the interleaver 23, into symbol data, and 25 is output from the mapping device 24. A spread modulator (spread modulation means) that spreads and modulates symbol data, 26 selects the optimal TFRC from a plurality of preset TFRCs according to the reception quality of the mobile station, and defines the TFRC Therefore, the adaptive processor (adaptive processing means) controls the transport block divider 21, the encoding processor 22, the mapping unit 24, and the spread modulator 25.

Fig. 7 is a block diagram showing the receiving device of the mobile station. In the figure, reference numeral 31 denotes the number of codes from the channelization code number given by the channelization code set CCS included in the downlink signaling. A despreader that recognizes the signal and despreads the spread modulation signal with the code number, 32 is a demapping device that converts symbol data output from the despreader 31 to bit data, and 33 is a demapping device 3 Dinterleaver that performs deinterleaving processing on the bit data output from 2, 3 4 is a decoding processor that decodes the transport block that is the bit data output from the interleaver 3 3, 3 5 Is 0 to 1 11 receivers, 3 6 is Ding! 〇Converter.

Next, the operation will be described.

When the base station transmits transmission information to the mobile station, the transmission information is supplied to the transport block divider 21 from the upper layer.

When the transmission information is given from the upper layer, the transport block divider 21 divides the transmission information into transport blocks. That is, the transmission information is divided so that the number of blocks of the transmission information matches the transport block size instructed by adaptive processor 26. Upon receiving the transport block from transport block divider 21, encoding processor 22 encodes the transport block at the encoding rate specified by adaptive processor 26. That is, the encoding processor 22 performs an error correction encoding process and adjusts the number of bits so that the number of bits of the transport block matches the number of bits of the physical channel. This processing is called rate matching.

When the interleaver 23 encodes the encoding processor 22 S transport block, the interleaver 23 performs an interleaving process on the transport block.

The interleave processing is performed for each channel, but the interleave processing is performed, for example, in a case where a memory having a row-by-column configuration exists, data is written to the memory in a column direction while data is read. The processing is performed in the direction of travel. By performing the interleave processing, it is possible to mitigate the long-term continuation of the level decrease caused by Doppler specific to mobile communication.

When the interleaver 23 performs the interleaving process, the mapping device 24 converts bit data that is output data of the interleaver 23 into symbol data. That is, data mapping is performed by the modulation method specified by the adaptive processor 26.Here, it is assumed that a plurality of bit strings are converted into QPSK or IQ symbol of 16 QAM. .

When the mapping device 24 converts the QPSK IQ symbol (see FIG. 8), the correspondence between the bit data input to the mapping device 24 and the symbol data output from the mapping device 24 is ninth. It looks like the figure.

In other words, the 4-bit input S such as S (0, 0) or (1, 1) For the street, the IQ symbol takes four values, such as (+0.707, + j0.70.77) and (—0.70.7, -j0.70.707).

Here, bit input 0 corresponds to +1 and bit input 1 corresponds to _1, and 1 / f 2 = so that the average power does not change at the input and output of the mapping unit 24 (to 1). A coefficient of 0.707 is provided.

When the mapping unit 24 converts the IQ symbols into 16 QAM IQ symbols (see FIG. 10), the bit data input to the mapping unit 24 and the symbol data output from the mapping unit 24 are used. Is as shown in Fig. 11.

That is, for 16 types of bit input, such as 4-bit power (0, 0, 0, 0) and (1, 1, 1, 1), the IQ symbol is (+0.316 2 , + j 0. 3 1 6 2) and (1 0.94 8 7,-j 0.94 8 7).

Here, bit input 0 corresponds to +1 and bit input 1 corresponds to 1 1 so that the average power does not change (become 1) at the input / output of the mapping device 24 1/1 0. = 0. 3 16 2 and 3 1 0 = 0.94 8 7 are given.

Upon receiving the symbol data from the matching device 24, the spread modulator 25 performs spread modulation of the symbol data with the number of codes specified by the adaptive processor 26. That is, the spread modulator 25 performs spread modulation using a scramble code or a channelization code.For example, when the number of codes is 5, spread modulation of symbol data is performed using five channelization codes. . '

The spread modulation signal output from spread modulator 25 is transmitted to the mobile station from the antenna after radio frequency conversion and filtering processing are performed. The transmission information of the base station is transmitted to the mobile station as described above, and the adaptive processor 26 adaptively switches the modulation method and the coding rate according to the reception quality of the mobile station. .

That is, upon receiving the feedback signal indicating the reception quality of the mobile station, the adaptive processor 26 refers to the feedback signal and selects an optimal TFRC from a plurality of TFRCs set in advance. .

Then, referring to the definition of the TFRC, the transport block size is output to the transport block divider 21, the coding rate is output to the coding processor 22, and the modulation scheme is set to the mapping unit 2. 4 and the number of codes is output to the spread modulator 25.

'Here, FIG. 12 is an explanatory diagram showing the definition contents of T FRC set in advance. In the example of Fig. 12, in addition to the six types of TFRC in Fig. 3, six types of TFRCs are additionally set, and TFRC (1) to (6) have a modulation method, a transport block size, and a code. Numbers and coding rates are defined.

FIG. 13 is an explanatory diagram showing the steps of the I or / I oc characteristic. For example, in the steps from TFRC (1) to TFRC (1.5), the characteristic difference of I o 1 "10 _£ ; Is 1.6 dB, the TFRC (3) force, and the TFRC (3.5) step have a characteristic difference of I or / I oc characteristic of 1.0 dB, and the characteristic difference is This is smaller than 2 dB, so that the I or ZI oc characteristic of the received signal of the mobile station does not fluctuate greatly without adding a power offset to the spread modulation signal as in the conventional example. Therefore, the reception quality does not significantly deteriorate.

FIG. 14 is an explanatory diagram showing the block error rate characteristics of TFRC (1) to (6) .In the example of FIG. 14, the TFRC (1) is transmitted with the smallest I or / I oc characteristic. Indicates that you can do it. That is, TFRC (1) Indicates that communication can be performed with the lowest required channel quality. For example, when the allowable value of the block error rate is BLER th, it is desirable to select TFRC (1) below the threshold A, and it is desirable to select TFRC (1.5) below the threshold B, and below the threshold C It is desirable to select TFRC (2) for TFRC (2.5) below threshold D, preferably TFRC (3) below threshold E, and TFRC below threshold F. It is preferable to select (3.5), TFRC (4) below threshold G, TFRC (4.5) below threshold H, and TFRC below threshold I. It is desirable to select (5), preferably TFRC (5.5) below threshold J, and TFRC (6) above threshold J.

Therefore, if adaptive processor 26 can receive a threshold (the upper limit of the I or ZI oc characteristic) as a feedback signal from the mobile station, adaptive processor 26 selects the optimal TFRC from a plurality of preset TFRCs. The base station notifies the mobile station of the transport block size, coding rate, modulation scheme, number of codes, etc. defined in the selected TFRC by downlink signaling.

Next, when the antenna of the mobile station receives the spread modulated signal transmitted from the base station, the spread modulated signal is subjected to radio frequency conversion, and then provided to despreader 31.

The despreader 31 recognizes the number of codes from the channelization code number provided by the channelization code set CCS included in the downlink signaling, and despreads the spread modulation signal with the code number. Outputs symbol data. ' Upon receiving the symbol data from the despreader 31, the demapping device 32 converts the symbol data into bit data according to the modulation scheme included in the downlink signaling.

When the demapping unit 32 performs QPSK demapping (see FIG. 15), the correspondence between the symbol data input to the demapping unit 32 and the bit data output from the demapping unit 32 is It looks like Figure 16.

Therefore, the original bit information (2 bits) can be extracted by using the I-axis and the Q-axis as thresholds. Here, the output of the hard decision bit of (0, 1) is shown, but it is also possible to output the soft decision bit.

When the demapper 32 performs 16 QAM demapping (see FIG. 17), the symbol data input to the demapper 32 and the bit data output from the demapper 32 are used. Figure 18 shows the correspondence.

Therefore, the original bit information (4 bits) can be extracted by using the I-axis, Q-axis, Q = -th, Q = th, i = -th, and i = th as thresholds. Here, the output of the hard decision bit of (0, 1) is shown, but the soft decision bit may be output. When the average power is 1, the threshold is set to th = 2 // 10 = 0.632. Also, the reception power of the mobile station is not always set to 1 so that it is set based on the CPICH power of the CPICH receiver 35 or the like. By the way, CPICH is a common pilot signal that is always transmitted.If the power distribution and SF difference with the packet signal are known, the CPICH receiver 35 receives the CPICH. A threshold can be set as a level reference. Upon receiving the bit data from the demapper 32, the interleaver 33 performs the interleave processing on the bit data. The interleaving of the interleaver 33 is the reverse of the interleaving of the interleaver 23.

Upon receiving the transport block, which is bit data, from the interleaver 33, the decoding processor 34 decodes the transport block according to the coding rate included in the downlink signaling. The transport block after decryption is output.

As is clear from the above, according to the first embodiment, when setting the TFRC (1) to (6) referred to by the adaptive processor 26, the step of the I or Z loc characteristic is smaller than 2 dB. Since TFRC (1) to (6) are set in such a way as to achieve the effect, it is possible to prevent an increase in the overhead and increase the link capacity.

In the first embodiment, the reference to the TFRC set as shown in FIG. 12 is shown. However, the setting of the TFRC is not limited to this. For example, as shown in FIG. You may refer to the TFRC set in.

The difference between Fig. 12 and Fig. 19 is that the modulation scheme of TFRC (3.5) is QPSK in Fig. 12, while the modulation scheme of TFRC (3.5) is Fig. 19 The method is 16 Q AM. Therefore, in FIG. 19, the coding rate of T FRC (3.5) is 0.4275. Embodiment 2.

In Embodiment 1 described above, the base station transmits transmission information to the mobile station. However, the mobile station may transmit transmission information to the base station. In this case, FIG. 6 shows the configuration of the adaptive modulation and coding apparatus of the mobile station, and FIG. FIG. 7 shows the configuration of the receiving device of the base station. Embodiment 3.

In the first and second embodiments, the case where TFRC (1) to (6) are set so that the step of the I or no I oc characteristic is smaller than 2 dB has been described. However, as shown in FIG. Then, TFRC (1) to (6) may be set so that the step of the I or / I oc characteristic is 1 dB. Thereby, an effect that a large variation of the IorZloc characteristic can be suppressed more than in the first and second embodiments.

Fig. 21 is an explanatory diagram showing the steps of the Γ r r / I oc characteristic.For example, in the step from TFRC (1) to TFRC (1.5), the characteristic difference of the I or / I oc characteristic is 1. In the steps from O d B, TFRC (3) to TFRC (3.5), the characteristic difference of the I or ZI oc characteristic is 1.0 dB, and the characteristic difference is set to 1 dB in any step. ing.

Therefore, even if a power offset is not added to the spread modulation signal as in the conventional example, the I / Ioc characteristic of the received signal of the mobile station or the base station does not fluctuate greatly, so that the reception quality is large. It does not cause deterioration.

In the third embodiment, the reference to the TFRC set as shown in FIG. 20 has been described. However, the setting contents of the TFRC are not limited to this. For example, the TFRC set as shown in FIG. Or refer to the TFRC.

The difference between Fig. 20 and Fig. 23 is that the modulation scheme of TFRC (3.5) is QPSK in Fig. 20, while the modulation scheme of TFRC (3.5) is Fig. 23. The method is 16 QAM. Therefore, TFRC (3 The coding rate power of 5) is SO.4.275. Embodiment 4.

Although not particularly mentioned in the first and second embodiments, as shown in FIGS. 24 and 25, TFRC (1) to (6) are set using the repetition of the rate matching. You may do it.

This makes it possible to reduce the variation of the transport block size without reducing the variation of the coding rate.

The number of repetitions in rate matching is the difference between the number of bits in the coding rate and the transport block size.

Therefore, for example, in the case of TFRC (1), the number of bits in the coding rate S is "1200" and the transport block size is "1200", so that the repetition of rate matching Becomes "0". In the case of TFRC (2), since the number of bits in the coding rate is "1800" and the transport block size is "1200", the repetition of rate matching is 6 0 0 ".

The block error rate characteristics of TFRC (1) to '(6) in the fourth embodiment are the same as in FIG. Embodiment 5.

Although not particularly mentioned in the third embodiment, as shown in FIGS. 26 and 27, TFRC (1) to (6) should be set using repetition of rate matching. It may be.

This allows the transport block size variation to be reduced without reducing the coding rate variation. 0203461

20 Curious.

The block error rate characteristics of TFRC (1) to (6) in the fifth embodiment are the same as those in FIG. Industrial applicability

As described above, in the adaptive modulation and coding apparatus according to the present invention, for example, the base station feedbacks the reception quality of the mobile station, and the base station adjusts the modulation scheme and coding rate based on the reception quality of the mobile station. Suitable for those that adopt the adaptive switching method.

Claims

The scope of the claims

1. Dividing means for dividing transmission information into transport blocks, an encoding means for encoding the transport block divided by the dividing means, and a transport block encoded by the encoding means Means for converting the bit data into bit data from bit data, spreading modulation means for spreading and transmitting the symbol data output from the mapping means, and mobile station from among a plurality of preset TFRCs. A base station comprising an optimum TFRC according to the reception quality of the TFRC, and an adaptive processing means for controlling the above-mentioned dividing means, the above-mentioned encoding means, the above-mentioned mapping means and the above-mentioned spreading modulation means according to the definition of the TFRC. In the adaptive modulation and coding apparatus of the station, when setting the TFRC referred to by the adaptive processing means,

An adaptive modulation and coding apparatus for a base station, wherein a plurality of TFRCs are set such that a step of 1orZIoc characteristic is smaller than a predetermined value.

2. When the mobile station is given an upper limit of the I or / I oc characteristic, the adaptive processing means is the most I or / I oc characteristic of the TFRC in which the I or / I oc characteristic does not exceed the upper limit. 2. The adaptive modulation and coding apparatus for a base station according to claim 1, wherein a TFRC having a larger value is selected.

3. The adaptive modulation and coding apparatus for a base station according to claim 1, wherein a plurality of T FRCs are set such that a step of the Ior / Ioc characteristic is 1 dB.

4. The adaptive modulation and coding of a base station according to claim 1, wherein a plurality of TFRCs are set using repetition of rate matching.

5. Dividing means for dividing the transmission information into transport blocks, an encoding means for encoding the transport block divided by the dividing means, and a transport block encoded by the encoding means. A transmitting unit that converts the symbol data output from the mapping unit into symbol data; a spread modulation unit that spreads and modulates the symbol data output from the mapping unit; and a spread modulation unit that transmits the symbol data. An optimal TFRC is selected according to the signal quality, and according to the definition of the TFRC, a mobile station having adaptive processing means for controlling the dividing means, the encoding means, the mapping means, and the spreading modulation means. In the adaptive modulation and coding apparatus, when setting the TFRC referred to by the adaptive processing means,

An adaptive modulation and coding apparatus for a mobile station, wherein a plurality of TFRCs are set such that a step of the Ior / Ioc characteristic is smaller than a predetermined value.

6. The adaptive processing means, when given the upper limit of the I or / I oc characteristic from the base station, has the largest I or ZI oc characteristic among the TFRCs whose I or Z oc characteristic does not exceed the upper limit. 6. The mobile station adaptive modulation and coding apparatus according to claim 5, wherein TFRC is selected.

7. The adaptive modulation and coding apparatus for a mobile station according to claim 5, wherein a plurality of TFRCs are set such that a step of the Ior / Ioc characteristic is 1 dB.

8. The mobile station adaptive modulation and coding according to claim 5, wherein a plurality of TFRCs are set using repetition of rate matching. twenty three