CN101043492B - Orthogonal frequency division multiplexing physical channel resource allocation method and device - Google Patents

Abstract

The invention discloses an OFDM physical channel resource allocation method to solve the problems of complex scheduling and poor frequency diversity capability in the prior art; Divide and multiplex the fixed number of subcarriers on the OFDM symbol to form the discrete resource channel DRCH, and the remaining subcarriers in the transmission frame form the centralized resource channel LRCH; and associate the user data with the LRCH according to the appropriate transmission mode for the user data to be transmitted or DRCH, and map the data to the subcarriers of the corresponding OFDM symbols. The invention also discloses a method and device for sending and receiving data at the same time.

Description

Orthogonal frequency division multiplexing physical channel resource allocation method and device

technical field

The invention relates to Orthogonal Frequency Division Utilization (OFDM) technology in the communication field, in particular to a method and device for allocating OFDM physical channel resources.

Background technique

Orthogonal Frequency Division Multiplexing (OFDM) is a multicarrier transmission technique that divides the frequency spectrum into many subcarriers, each of which is modulated with a lower data rate. By assigning different subcarriers to different users, multiple access of OFDM can be realized, that is, OFDMA. Each narrowband subcarrier adopts a different modulation method, such as QAM16, QAM8, etc., and then adopts an inverse fast Fourier transform (IFFT) to provide OFDM modulation. The data to be transmitted is mapped to OFDM symbols, and after IFFT, a cyclic prefix is added and sent out. The receiving end uses FFT to decipher the OFDM symbol and take out the data mapped to the symbol.

In the current technology, there are mainly two ways of allocating physical channel resources. One is a centralized allocation (localized) approach, and the other is a discrete allocation (distributed) approach.

As shown in Figure 1, the centralized allocation method divides the entire frequency band into several subbands. Each subband consists of consecutive subcarriers. According to the channel quality information (CQI) of each subband fed back by the user, the base station allocates resources of the physical channel to the user in units of subbands on the time-frequency plane. In this way, users can avoid deep fading frequency bands through selection and scheduling, and effectively combat frequency selective fading. Therefore, the centralized distribution method has higher transmission efficiency. However, the centralized allocation method requires CQI feedback of each subband, and the load of the reverse control channel is relatively large. Moreover, for users moving at high speed, since the channel quality changes too fast, the CQI fed back cannot reflect the current channel quality. Therefore, the centralized distribution method is only suitable for low-speed users.

The way of discrete allocation is shown in Figure 2, and the data of each user is scattered on the entire time-frequency plane. For the discrete allocation method, the base station only needs to know the average CQI of the entire frequency band, so the load of the feedback link is relatively small. It is suitable for data services with small data packets, such as voice services. Since the data is scattered over the entire frequency band, the discrete allocation method has a frequency diversity gain, which is suitable for high-speed movement and public control channels, etc., but its transmission efficiency is not as high as that of the centralized allocation method.

It can be seen that the above two methods have their own advantages and disadvantages. In order to make full use of channel resources, the multiplexing of the two methods must be considered.

In the prior art, a multiplexing scheme of a centralized allocation mode and a discrete allocation mode is shown in Figure 3, and a subframe (subframe) is drawn in Figure 3, which is composed of 7 symbols (long squares) in the time direction, The allocation steps for a single subframe are:

First allocate resources to the centralized users (as shown in the figure, centralized users 1, 2, 3, 4, ..., 12), and then the discretely allocated users (as shown in the picture, centralized users 1 and 2) in the centralized allocated resources Redistribution in resources, overwriting units originally allocated to centralized mapping, is called "punching". In Fig. 3, users allocated discretely, how the frequency allocation varies with time (ie frequency hopping pattern).

In Figure 3, the amount of data contained in each sub-band (such as the uppermost slash block) allocated to centralized allocation users (the slash rectangle) is not fixed, and will vary with the number of discrete allocation "punches", Thus greatly increasing the complexity of scheduling. Because the data packets allocated by the upper layer need to be reassembled and divided before they can be mapped and allocated, so as to adapt to the change in the size of allocation blocks in different concentrations. Moreover, the division ratio of each subframe is different and needs to be determined through calculation.

Secondly, in Fig. 3, when receiving the demodulation data, the users allocated centrally need to know which of the allocated blocks are occupied by the users allocated discretely. In this way, it is necessary to notify the centrally allocated users of this information in the forward control channel, thereby increasing the load of the forward control channel.

As shown in FIG. 4 , another scheme for multiplexing the centralized allocation mode and the discrete allocation mode in the prior art divides the entire frequency band resource into two parts, the centralized mapping area and the discrete mapping area, at equal intervals. The resources of the centralized mapping part are scheduled and allocated to the users of the centralized mapping according to the CQI feedback. The user allocation method of discrete mapping is shown as discrete user 1 and discrete user 2 in the figure. Dispersed allocation in frequency, no change in time. There are following deficiencies in this scheme:

1. 50% of the frequency bands are exclusively occupied by users allocated centrally, and users allocated discretely cannot allocate frequencies to these frequencies, that is to say, frequency diversity cannot be performed on these frequencies.

2. Since the degree of dispersion of the discrete allocation part on the time-frequency plane is not high enough, the way of dispersion is too single. For example, the frequency corresponding to the discrete user 1 does not change in time, which increases the probability of mutual interference between cells in the wireless communication system.

3. The resource allocation ratio between centrally allocated users and discretely allocated users is too fixed. In practice, however, the data volumes of users allocated centrally and users distributed discretely are often unbalanced. For example, there are often more users moving at a low speed than those moving at a high speed. If this allocation method is used fixedly, it will easily cause a great waste of physical channel resources, which is not desired by the system design.

4. The scheduling granularity of centralized allocation is the same as that of discrete allocation (as shown in Figure 4, centralized user 1 is composed of 12×7 small squares, which is the scheduling granularity of centralized allocation. And discrete user 1 is also composed of 12×7 small squares. Composed of 7 small squares, it is the scheduling granularity of discrete allocation). This is not conducive to the allocation of different services. In practice, the minimum granularity required for discrete allocation (considering services with small data packets such as voice) is much smaller than the minimum granularity for centralized allocation.

In short, using the existing solution, there are problems such as complex scheduling and multiplexing signaling, poor ability to resist inter-cell interference, poor ability to frequency diversity, and complex data block segmentation.

Contents of the invention

The invention provides an OFDM physical channel resource allocation method to solve the problems of complex scheduling and poor frequency diversity capability in the prior art.

The present invention provides a method and device for sending and receiving data to solve the problems in the prior art of complex scheduling and multiplexing signaling, poor ability to resist inter-cell interference, and complex data block segmentation.

The invention provides the following technical solutions:

A kind of orthogonal frequency division multiplexing physical channel resource allocation method, comprises the step: in a transmission frame definition is formed discrete resource channel DRCH by the fixed number of sub-carriers scattered on each orthogonal frequency division multiplexing OFDM code element, by The rest of the subcarriers in the transmission frame form the centralized resource channel LRCH, wherein the ratio of the number of subcarriers of DRCH and LRCH contained in each transmission frame in different multiplexing modes is different; and the data of different users are divided into suitable for DRCH transmission and suitable for DRCH transmission LRCH transmission, and according to the amount of data that DRCH and LRCH need to transmit in the current frame, select the corresponding multiplexing mode, associate user data with LRCH or DRCH, and map the data to the subcarrier of the corresponding OFDM symbol.

In a preferred manner, resource channels have the following characteristics:

Multiple DRCHs and multiple LRCHs are formed in one transmission frame, and are identified by corresponding indexes respectively.

The number of subcarriers that make up DRCH on each OFDM symbol is the same and fixed; the spacing of subcarriers that make up DRCH on each OFDM symbol is distributed over the entire frequency domain; the subcarriers that make up DRCH on each OFDM symbol, etc. The intervals are distributed over the entire frequency domain.

In each subband composed of multiple consecutive subcarriers, the number of subcarriers occupied by the DRCH is the same.

On different OFDM symbols, the frequency of the subcarriers that make up the DRCH is hopped; the mode of frequency hopping is generated by a frequency hopping sequence; each cell selects a different frequency hopping sequence according to the principle of minimum frequency collision.

The number of subcarriers included in the LRCH is greater than or equal to the number of subcarriers included in the DRCH, and is an integer multiple of the number of subcarriers included in the DRCH.

A method for sending data, comprising the steps of: distinguishing data of different users into suitable for DRCH transmission and suitable for LRCH transmission; The user data is associated to the corresponding resource channel, which includes a discrete resource channel DRCH composed of a fixed number of subcarriers scattered on each OFDM symbol in a transmission frame, and the remaining subcarriers in the frame Carriers form a centralized resource channel LRCH, in which the ratio of the number of subcarriers of DRCH and LRCH contained in each transmission frame in different multiplexing modes is different; the data is coded and modulated to generate modulation symbols, and mapped to the subcarriers of the corresponding OFDM symbols Above; inverse fast Fourier transform processing is performed on subcarriers and OFDM symbols are sent.

In a preferred manner, when associating data with resource channels, the number of subcarriers contained in each DRCH and LRCH among different multiplexing modes is an integer multiple of the smallest number of subcarriers contained in DRCH in all multiplexing modes.

A method for receiving data, comprising the steps of: receiving an OFDM symbol of a data frame, and obtaining control information of a resource channel from a control channel, the resource channel comprising OFDM codes dispersed in a transmission frame A fixed number of subcarriers on the element constitutes the discrete resource channel DRCH, and the rest of the subcarriers in the frame form the centralized resource channel LRCH, where the ratio of the number of subcarriers of DRCH and LRCH contained in each transmission frame in different multiplexing modes is different , and suitable for DRCH transmission and LRCH transmission according to the different user data that needs to be transmitted, and according to the size of the amount of data that DRCH and LRCH need to transmit in the current frame, select the corresponding multiplexing mode; carry out fast Fourier transform to the OFDM code, The subcarriers on each OFDM symbol associated with the DRCH and LRCH are recovered; the modulation symbols are extracted from the subcarriers, and the modulation symbols are demodulated and decoded to recover data.

A transmitting device, including: used to distinguish the data of different users into suitable for DRCH transmission and suitable for LRCH transmission, according to the size of the amount of data that DRCH and LRCH need to transmit in the current frame, select the corresponding multiplexing mode, and the users who need to transmit The data is associated to the corresponding resource channel, which includes a discrete resource channel DRCH composed of a fixed number of subcarriers scattered on each OFDM symbol in a transmission frame, and the remaining subcarriers in the frame The unit that forms the centralized resource channel LRCH, in which the ratio of the number of subcarriers of DRCH and LRCH contained in each transmission frame in different multiplexing modes is different; the data is coded and modulated to generate modulation symbols, and mapped to the sub-carriers of the corresponding OFDM symbols A unit on a carrier; a unit that performs inverse fast Fourier transform processing on subcarriers and sends OFDM symbols.

A receiving device, comprising: used to receive OFDM symbols of a data frame, and obtain control information of a resource channel from a control channel, the resource channel includes being dispersed on each OFDM symbol of a transmission frame A fixed number of subcarriers constitutes the discrete resource channel DRCH, and the rest of the subcarriers in the frame form the unit of the centralized resource channel LRCH, where the ratio of the number of subcarriers of DRCH and LRCH contained in each transmission frame in different multiplexing modes is different , and according to the different user data that needs to be transmitted, it is suitable for DRCH transmission and LRCH transmission, and according to the size of the data volume that DRCH and LRCH need to transmit in the current frame, select the corresponding multiplexing mode; for performing fast Fourier transform on the OFDM code Convert and recover the unit of the subcarrier on each OFDM symbol associated with the DRCH and LRCH; the unit used to extract the modulation symbol from the subcarrier, and demodulate and decode the modulation symbol to recover the data.

The beneficial effects of the present invention are as follows:

1. In the present invention, the position of the part occupied by discrete users is determined in the protocol, and no additional signaling is required for notification. Therefore, there are fewer allocation control signaling, and the scheduling and multiplexing signaling is simple; However, in the prior art, the DRCH user needs to know which parts are punctured by the LRCH user, and this information requires more signaling to notify the user terminal.

2. Since the number of subcarriers in a frame contained in each DRCH is an integer multiple of the number of subcarriers contained in each LRCH, this greatly facilitates the definition of the upper layer logical data packet size and reduces the need for logical data segmentation during scheduling. The complexity when the package is a physical data package;

3. The sub-carriers associated with the DRCH are evenly distributed in the entire time-frequency plane. Such uniformity not only facilitates the design of frequency hopping patterns, but also facilitates users of DRCH transmission to obtain complete diversity in the entire time-frequency domain.

4. The number of subcarriers contained in each DRCH is smaller than that contained in each LRCH, which is conducive to the segmentation of logical data packets suitable for small data packets and services requiring small delays (such as VOIP services, etc.). Because each LRCH is associated with the CQI of each sub-band, if the sub-bands are divided into smaller ones, the number of sub-bands will be larger, and thus the number of CQIs to be fed back will be larger, which will greatly increase the load of the feedback link. Therefore, it is more realistic to use DRCH to associate with small data packet real-time services;

5. The DRCH hops frequency on the entire frequency, and can conveniently apply frequency hopping sequences with good performance, such as RS sequences and Latin sequences. Different cells use different RS sequences or Latin sequences, which can achieve a good inter-cell interference averaging effect, thereby improving the frequency reuse rate of users at the edge of the cell.

6. A simple way is used to coordinate the problem of the proportion of traffic associated with DRCH and LRCH. In the present invention, the ratio of the two can be changed by selecting a mode, the method is simple and practical, and no additional signaling is required. In the prior art, the ratio of the total number of subcarriers associated with all DRCHs to the total number of subcarriers associated with all LRCHs is fixed at 1:1. However, in practice, the ratio of the two data often changes, and in most cases, there are more users moving at a low speed than users moving at a high speed, so it is not appropriate to fix it at 1:1.

Description of drawings

FIG. 1 is a schematic diagram of the centralized allocation of channel resources on the time-frequency plane in the prior art;

FIG. 2 is a schematic diagram of a discrete allocation method of channel resources on the time-frequency plane in the prior art;

FIG. 3 is a schematic diagram of resource allocation in an overlay manner in the process of centralized allocation and discrete allocation of channel resources on the time-frequency plane in the prior art;

FIG. 4 is a schematic diagram of resource allocation in a fixed manner during the centralized allocation and discrete allocation of channel resources in the prior art on the time-frequency plane;

FIG. 5 is a schematic structural diagram of a transmitter in a single antenna system in an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of a receiver in a single antenna system in an embodiment of the present invention;

FIG. 7 is a flow chart of sending data in an embodiment of the present invention;

FIG. 8 is a flow chart of receiving data in an embodiment of the present invention;

FIG. 9A and FIG. 9B are schematic diagrams of channel resource allocation on the time-frequency plane in mode 1 and mode 2 respectively in the embodiment of the present invention.

Detailed ways

In a multi-user Orthogonal Frequency Division Multiplexing (OFDMA) environment, a data frame is the smallest codec data block for transmission, usually consisting of several Orthogonal Frequency Division Multiplexing (OFDM) symbols. In order to efficiently transmit data of users with different moving speeds and different service types, each user data is associated with a resource channel (RCH), and the RCH is composed of several subcarriers on multiple OFDM symbols in a data frame. The RCH is divided into two types according to the correlation between the composed subcarriers: a concentrated resource channel (LRCH) and a discrete resource channel (DRCH).

In the present invention, LRCH is composed of a fixed number of continuous subcarriers in a frame. According to the frequency-domain correlation between subcarriers, a number of consecutive subcarriers in the entire frequency band within a data frame are divided into groups, and each group is called a subband. In each subband except the one occupied by the DRCH, other subcarrier groups correspond to one LRCH. DRCH consists of a fixed number of sub-carriers scattered over different OFDM symbols within a frame. When transmitting user data, according to the suitable transmission mode of the user data, that is, the transmission mode of centralized allocation of channel resources or the transmission mode of discrete allocation of channel resources, the user data is associated with LRCH or DRCH, and then the data is mapped to the corresponding channel according to the existing method. on the subcarriers of the OFDM symbol.

In order to facilitate users of DRCH transmission to obtain complete diversity in the entire time-frequency domain, the number of subcarriers that make up DRCH is fixed on each OFDM symbol and distributed at intervals throughout the frequency domain; the better way is to distribute at equal intervals .

In order to obtain a better average effect of inter-cell interference and improve the frequency reuse rate of users at the edge of the cell, the frequencies of the subcarriers that make up the DRCH on different OFDM symbols change. The frequency hopping mode can be changed from the traditional frequency hopping sequence Generate, such as RS sequence, Latin sequence, etc. Each cell uses a different frequency hopping sequence based on the principle of minimum frequency collision, and each DRCH can be identified by a frequency hopping pattern on a different OFDM symbol.

The number of subcarriers included in an LRCH and the number of subcarriers included in a DRCH are determined before the communication system is established. In this embodiment, the number of subcarriers included in the DRCH is less than or equal to the number of subcarriers included in the LRCH, and is an integer multiple of the number of subcarriers included in the LRCH, that is, the number of subcarriers included in the LRCH is an integer multiple of the number of subcarriers included in the DRCH. This can be realized through the number of subcarriers of DRCH and LRCH on each OFDM symbol, as long as the number of subcarriers contained in LRCH and each OFDM symbol is a multiple of the number of subcarriers contained in DRCH. The number of sub-carriers included in the DRCH is related to the data packet size of the low-rate real-time service to be served by the communication system, such as the data packet size of VOIP.

A frame contains multiple DRCHs and multiple LRCHs, and their numbers are fixed before the system is established, and are identified by DRCH indexes and LRCH indexes respectively, and the index information is notified to the mobile terminal through the common control channel. The subcarriers allocated to these DRCHs are evenly distributed in the frequency domain as far as possible, and it is ensured that in each subband, the number of subcarriers occupied by these DRCHs is the same.

According to different proportions of subcarrier numbers of DRCH and LRCH included in a frame, different multiplexing modes are preset before system establishment. The number of multiplexing modes is determined before the system is established according to the flexibility required by the system and the complexity of scheduling. The greater the number, the higher the flexibility, and the higher the complexity of dividing the LRCH logical data packets during scheduling. The type of the mode can be identified by the number of DRCHs in a frame, which is determined before the system is established. Since the index information of the DRCH is propagated on the public channel, adding a mode does not require additional signaling. The number of subcarriers contained in each DRCH and LRCH among different multiplexing modes is an integral multiple of the smallest DRCH in all modes.

As shown in FIG. 5 , the transmitter in the single antenna system includes: encoding unit 11 , modulation unit 12 , mapping unit 13 , IFFT unit 14 and antenna 20 (not all processing units are shown in the figure). The encoding unit 11 is used to encode the data packet; the modulation unit 12 is used to modulate the encoded data to generate a modulation symbol packet; the mapping unit 13 is used to map the symbols in the modulation symbol packet to the subcarriers of the OFDM symbol; The IFFT unit 14 is used to perform an inverse discrete fast Fourier transform on the associated data on each OFDM symbol to obtain the OFDM symbol in the time domain; the antenna 20 is used to transmit the OFDM symbol.

Referring to FIG. 6 , the receiver in the single antenna system includes: an antenna 40 , a Fast Fourier Transform FFT unit 31 , an inverse mapping unit 32 , a demodulation unit 33 and a decoding unit 34 . Antenna 40 is used to receive the OFDM symbol of the data frame; FFT unit 31 is used to carry out fast compound leaf transform processing to OFDM symbol, obtains the OFDM symbol of frequency domain; Demapping unit 32 is used for from the subcarrier of OFDM symbol The modulation symbol is extracted; the demodulation unit 33 is used to demodulate the modulation symbol to obtain coded data; the decoding unit 34 is used to decode the demodulated data to recover user data.

As shown in Figure 7, the main processing flow of data sent by the transmitter is as follows:

Step 700, the base station first distinguishes the data of different users from the upper layer into two types suitable for DRCH transmission and suitable for LRCH transmission.

The algorithm for distinguishing is determined by the scheduling layer (the same as the existing method, which is not within the scope of the present invention). The basic principle is that users with lower moving speed and users with higher transmission rate are suitable for LRCH transmission; users with high moving speed, transmission Users with low rate and high real-time requirements, public control signaling services, etc. are suitable for DRCH transmission.

In step 710, the base station selects an appropriate multiplexing mode according to the amount of data that needs to be transmitted in the current frame of the DRCH and LRCH.

Step 720, the logic packet that communication system upper layer (such as MAC layer) comes over, after being distinguished into DRCH type and LRCH type, do following processing:

If it is a DRCH type, then according to the average channel state information (CQI) of the entire frequency band fed back by the entire transmitter, determine the appropriate coding and modulation scheme (MCS), and thus calculate the bits that can be transmitted by each DRCH The number is the size of the DRCH physical package. Divide the DRCH logical packet into several DRCH physical packets according to the size of the DRCH physical packet.

If it is an LRCH type, a scheduling algorithm is used to associate this logical data packet with the LRCH (the scheduling algorithm is the same as the existing method, which is not within the scope of the present invention). The basic principle is that according to the CQI of each subband, the LRCH corresponding to this subband is allocated to users with better CQI on this subband. After the correlation between the logical data packet and the LRCH is determined, the CQI of the subband where the LRCH is located can be used to determine the coding and modulation mode adopted, thereby determining the number of bits that can be transmitted by each LRCH. According to this number of bits, the logical data packet is divided into LRCH physical data packets,

In step 730, the encoding unit 11 encodes the physical data packet.

In step 740, the modulation unit 12 modulates the coded data to generate modulation symbol packets.

In step 750, the mapping unit 13 associates (maps) the symbols in the divided modulation symbol package to the subcarriers of multiple OFDM symbols in the current frame corresponding to each DRCH or LRCH.

Step 760, when all the subcarriers in a frame are associated with the corresponding data symbols, the IFFT unit 14 performs an inverse discrete fast Fourier transform (IFFT) on the associated data on each OFDM symbol to obtain the OFDM in the time domain symbol.

Step 770, the antenna 20 continuously transmits multiple OFDM symbols in one frame.

Referring to Figure 8, the main processing flow of receiving data at the receiving end is as follows:

In step 800, the antenna 40 receives OFDM symbols in the time domain, and continuously receives OFDM symbols of one frame.

In step 810, the FFT unit 31 performs fast Fourier transform on the OFDM symbols to obtain OFDM symbols in the frequency domain. Different sampling points on the symbol correspond to different frequencies.

Step 820, the mobile terminal user obtains control information such as the multiplexing mode, the type of RCH, and the index number of LRCH or DRCH from the control channel.

Step 830, the demapping unit 32 performs the following processing after distinguishing between DRCH type and LRCH type:

If the user is of the DRCH type, according to the index number of the DRCH, the corresponding modulation symbols are obtained on the subcarriers on each OFDM symbol associated with the DRCH predefined by the system;

If the user is of the LRCH type, according to the index number of the LRCH, the corresponding modulation symbols are obtained from the subcarriers on each OFDM symbol associated with the LRCH predefined by the system.

In step 840, the demodulation unit 33 demodulates the modulation symbols according to the MCS corresponding to the DRCH or according to the MCS of the subband where the LRCH is located.

In step 850, the decoding unit 34 decodes the demodulated data to recover user data.

For the data obtained by decoding the DRCH, a physical data packet of the user is formed, and all physical data packets of the frame corresponding to the user are combined into a logical data packet of the user, and sent to the upper layer (such as the MAC layer) of the communication system. For the data of the LRCH obtained by decoding, a physical data packet of the user is formed, all physical data packets corresponding to the user are combined into a logical data packet of the user, and sent to the upper layer (such as the MAC layer) of the communication system.

Further illustrate with a specific example below, this specific example is not intended to limit the present invention:

As shown in Fig. 9A and Fig. 9B, there are two multiplexing modes of Mode 1 and Mode 2 respectively, the difference lies in the number of sub-carriers included in the LRCH.

As shown in FIG. 9A , the number of effective subcarriers in a certain communication system is 384. According to the frequency domain correlation of subcarriers, it is divided into 12 subbands, each subband is composed of 32 continuous subcarriers (the first 3 subbands and the last subband are drawn in Figure 9A and Figure 9B, and the middle part is omitted not marked out).

A data frame of the system is defined as 7 OFDM symbols. According to the aforementioned principles, in order to make the LRCH a multiple of the number of subcarriers contained in the DRCH, and to associate the DRCH with the lowest rate real-time service, the number of subcarriers contained in each OFDM symbol in a DRCH is set to 4, and the LRCH in The number of subcarriers included in each OFDM symbol is a multiple of 4, such as 16, 24, and so on. The number of subcarriers included in one DRCH is the number of subcarriers included in each OFDM symbol multiplied by the number of OFDM symbols in each frame. In this example, there are 4×7=28 subcarriers, and assuming that the modulation mode adopted is 8PSK, then the number of bits that can be transmitted by one DRCH is 84, that is, the physical packet size of one DRCH is 84. Without loss of generality, if the lowest rate real-time service considered is a voice service, a voice packet is usually 80 bits, plus a redundancy check code of 84 bits, so voice packets can be easily transmitted on the DRCH, greatly reducing It reduces the complexity of scheduling layer segmentation and reduces the waste of subcarrier resources.

Since one DRCH is associated with 4 subcarriers on each OFDM symbol. According to the principles of the present invention, the four subcarriers are evenly distributed over the entire frequency band. For example, on the first OFDM symbol, the subcarriers are numbered sequentially from 0 to 383, and the subcarrier numbers associated with the DRCH are 0, 32×3+0=96, 32×6+0=192, 32×9 +0=288 and so on 4. For the second OFDM symbol, there is an offset relative to the subcarrier on the first OFDM symbol. This offset is determined by a frequency hopping sequence, and the frequency hopping sequence can use RS sequence, Latin sequence, etc. For example, in this example, the frequency hopping sequence is 0, 32+17=49, 26, 32×2+11=75, 12, 32×1+29=61, 32×1+6=38, etc., that is, the first In one OFDM symbol, the offset of the first subcarrier in the 4 subcarriers associated with DRCH1 is 0, the offset in the second symbol is 49, and so on (the black slash in the figure part of the subcarrier shown).

The number of subcarriers included in one LRCH is set according to system requirements. For example, in mode 1 shown in Figure 9A, the number of subcarriers contained in an LRCH is 24×7, where 24 is the number of subcarriers associated with the LRCH on each OFDM symbol, and 7 is the number of OFDM symbols in a frame number. There are a total of 12 subbands in the entire frequency band, corresponding to 12 LRCHs. Therefore, the sum of subcarriers associated with these LRCHs in each OFDM symbol is 24×12=288. The number of remaining subcarriers is 384-288=96. The 96 DRCHs are associated with DRCHs. Since each DRCH is associated with 4 subcarriers in one OFDM symbol, there are 96/4=24 DRCHs in total. These subcarriers reserved for DRCH are evenly distributed in the entire frequency domain, as in mode 1 of FIG. 9 , there is one white subcarrier for every three, which is a subcarrier reserved for DRCH. That is to say, every time DRCH1 is offset by 4 subcarriers, a new DRCH is obtained. A total of 23 offsets are possible. In each subband except the subcarriers associated with the DRCH, the remaining subcarriers are associated with an LRCH. In this way, subcarriers on multiple OFDM symbols in one frame are associated with 24 DRCHs and 12 LRCHs respectively.

In mode 2 shown in FIG. 9B , a similar method is used to associate subcarriers on multiple OFDM symbols in a frame with 48 DRCHs and 12 LRCHs respectively, and the number of subcarriers associated with each DRCH is 28, and the number of subcarriers associated with each LRCH is 16×7=112. Since the allocation information of DRCH and LRCH is transmitted on the common channel. Therefore, each terminal can determine the multiplexing mode to be adopted according to the number of DRCHs without additional signaling. In each mode, the number of subcarriers included in the LRCH is an integral multiple of the number of subcarriers included in the DRCH. Therefore, if the packets transmitted by LRCH are used, if the LRCH resources in the current frame are insufficient, they can be easily divided into DRCH for transmission, or saved for transmission in the next frame. And the relationship of these integer multiples is convenient for the design of the logical data packet of the upper layer, because in the current communication system, the size of the logical data packet from the upper layer is fixed, if the size of the physical data packet is not an integer multiple, the logical data packet from the upper layer Packets need to go through complex segmentation to fit the size of the physical packet, and it is easy to generate leftover data.

The process of processing and transmitting the logical data packets from the upper layer is as described above. First of all, it is divided into those suitable for DRCH and those suitable for LRCH. Then select an appropriate multiplexing mode and an appropriate MCS, and associate it with the LRCH or DRCH. Computation is partitioned into physical packets. Modulation symbols obtained after coding and modulation are sequentially placed on the subcarriers of each OFDM symbol related to the corresponding LRCH or DRCH. After each OFDM code element undergoes IFFT, it becomes a time-domain signal and is sent out through the antenna.

According to the obtained time domain signal at the receiving end, FFT changes it into an OFDM symbol. According to the mode information obtained on the control channel and the assigned LRCH or DRCH index, each mobile terminal takes out the modulation symbol from the subcarrier of each OFDM symbol associated with the LRCH or DRCH, and then demodulates, decodes, and restores Physical data packets are combined into logical data packets and sent to the upper layer.

In summary, we can see that:

1. In mode 1, the number of subcarriers in a frame associated with all DRCHs is 1/3 of the number of subcarriers in a frame associated with all LRCHs. In mode 2, the number of subcarriers in a frame associated with all DRCHs is equal to the number of subcarriers in a frame associated with all LRCHs. In this way, the proportion of DRCH and LRCH data volumes can be coordinated by selecting the two modes.

2. The number of subcarriers in a frame contained in each DRCH is an integer multiple of the number of subcarriers contained in each LRCH, which greatly facilitates the definition of the size of the upper layer logical data packet and reduces the need for splitting logical data packets during scheduling. The complexity when it is a physical packet.

3. As shown in FIGS. 9A and 9B , the subcarriers associated with the DRCH are evenly distributed in the entire time-frequency plane. Such uniformity not only facilitates the design of frequency hopping patterns, but also facilitates users of DRCH transmission to obtain complete diversity in the entire time-frequency domain.

4. The number of subcarriers contained in each DRCH is smaller than that contained in each LRCH, which is conducive to the segmentation of logical data packets suitable for small data packets and services requiring small delays (such as VOIP services, etc.). Because each LRCH is associated with the CQI of each sub-band, if the sub-bands are divided into smaller ones, the number of sub-bands will be larger, and thus the number of CQIs to be fed back will be larger, which will greatly increase the load of the feedback link. Therefore, it is more realistic to use DRCH to correlate with small data packet real-time services.

5. The DRCH hops frequency on the entire frequency, and can conveniently apply frequency hopping sequences with good performance, such as RS sequences and Latin sequences. Different cells use different RS sequences or Latin sequences, which can achieve a good inter-cell interference averaging effect, thereby improving the frequency reuse rate of users at the edge of the cell.

6. Less allocation control signaling: In the existing puncturing technical solution, DRCH users need to know which parts are punctured by LRCH users, and this information requires more signaling to notify user terminals. However, in the present invention, the position of the part occupied by the discrete user is determined in the protocol, and no additional signaling is required for notification.

7. The problem of the ratio of traffic associated with DRCH and LRCH is coordinated in a simple manner. In the prior art, the ratio of the total number of subcarriers associated with all DRCHs to the total number of subcarriers associated with all LRCHs is fixed at 1:1. In reality, the ratio of the two data often changes, and in most cases, users who move at a low speed outnumber those who move at a high speed. So it is not appropriate to fix it at 1:1. However, in the present invention, the ratio of the two can be changed by selecting a mode, the method is simple and practical, and no additional signaling is required.

Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and equivalent technologies, the present invention also intends to include these modifications and variations.

Claims (43)

1. a kind of OFDM physical channel resource allocation method is characterized in that, comprises the steps: In a transmission frame, the discrete resource channel DRCH is defined by a fixed number of subcarriers scattered on each OFDM symbol, and the centralized resource channel LRCH is composed of the rest of the subcarriers in the transmission frame. The ratio of the number of subcarriers of DRCH and LRCH contained in each transmission frame in the pattern is different; and Divide the data of different users into suitable for DRCH transmission and suitable for LRCH transmission, and according to the amount of data that DRCH and LRCH need to transmit in the current frame, select the corresponding multiplexing mode, associate user data with LRCH or DRCH, and map the data to the subcarriers of the corresponding OFDM symbols. 2. The method according to claim 1, wherein a plurality of DRCHs and a plurality of LRCHs are formed in one transmission frame, which are respectively identified by corresponding indexes. 3. The method according to claim 1, wherein the number of subcarriers constituting the DRCH on each OFDM symbol is the same and fixed. 4. The method according to claim 3, wherein the spacing of subcarriers constituting the DRCH on each OFDM symbol is distributed over the entire frequency domain. 5. The method according to claim 4, characterized in that the subcarriers constituting the DRCH on each OFDM symbol are equally spaced across the entire frequency domain. 6 . The method according to claim 5 , wherein in each subband formed by multiple consecutive subcarriers, the number of subcarriers occupied by the DRCH is the same. 7. The method according to any one of claims 1 to 6, characterized in that, on different OFDM symbols, frequency hopping of the subcarriers constituting the DRCH occurs. 8. The method according to claim 7, wherein the frequency hopping pattern is generated by a frequency hopping sequence. 9. The method according to claim 7, wherein each cell selects a different frequency hopping sequence according to the principle of minimum frequency collision. 10. The method according to claim 7, wherein the number of subcarriers included in the LRCH is greater than or equal to the number of subcarriers included in the DRCH, and is an integer multiple of the number of subcarriers included in the DRCH. 11. A method for sending data, comprising the steps of: Differentiate the data of different users into those suitable for DRCH transmission and those suitable for LRCH transmission, select the corresponding multiplexing mode according to the amount of data that needs to be transmitted by the current frame on DRCH and LRCH, and associate the user data that needs to be transmitted with the corresponding resource channel. The resource channel includes the discrete resource channel DRCH composed of a fixed number of subcarriers scattered on each OFDM symbol in a transmission frame, and the centralized resource channel LRCH composed of the rest of the subcarriers in the frame. The ratio of the number of subcarriers of DRCH and LRCH contained in each transmission frame in the mode is different; Encoding and modulating the data to generate modulation symbols, and mapping to the subcarriers of the corresponding OFDM symbols; Inverse fast Fourier transform processing is performed on subcarriers and OFDM symbols are sent. 12. The method according to claim 11, wherein a plurality of DRCHs and a plurality of LRCHs are formed in one transmission frame, each identified by a corresponding index, and the index information is notified to the receiving end through a common control channel. 13. The method according to claim 12, wherein the number of subcarriers contained in each DRCH and LRCH among different multiplexing modes is an integer multiple of the smallest number of subcarriers contained in DRCH in all multiplexing modes. 14. The method according to claim 11, wherein in the one transmission frame, the number of subcarriers constituting the DRCH on each OFDM symbol is the same and fixed. 15. The method according to claim 14, characterized in that the spacing of subcarriers constituting the DRCH on each OFDM symbol is distributed over the entire frequency domain. 16. The method according to claim 15, characterized in that the subcarriers constituting the DRCH on each OFDM symbol are equally spaced across the entire frequency domain. 17. The method according to claim 16, wherein in each sub-band formed by multiple consecutive sub-carriers, the number of sub-carriers occupied by the DRCH is the same. 18. The method according to any one of claims 11 to 17, characterized in that, on different OFDM symbols, frequency hopping of subcarriers constituting the DRCH occurs. 19. The method of claim 18, wherein the frequency hopping pattern is generated by a frequency hopping sequence. 20. The method according to claim 18, wherein each cell selects a different frequency hopping sequence according to the principle of minimum frequency collision. 21. The method according to claim 18, wherein the number of subcarriers included in the LRCH is greater than or equal to the number of subcarriers included in the DRCH, and is an integer multiple of the number of subcarriers included in the DRCH. 22. A method for receiving data, comprising the steps of: Receive the OFDM symbol of a data frame, and obtain the control information of the resource channel from the control channel. The resource channel includes a fixed number of subcarriers scattered on each OFDM symbol in a transmission frame. The resource channel DRCH, and the centralized resource channel LRCH composed of the remaining subcarriers in the frame, where the ratio of the number of subcarriers of DRCH and LRCH contained in each transmission frame in different multiplexing modes is different, and different user data are transmitted according to needs Suitable for DRCH transmission and LRCH transmission, and select the corresponding multiplexing mode according to the amount of data that DRCH and LRCH need to transmit in the current frame; Performing fast Fourier transform on the OFDM code, recovering subcarriers on each OFDM symbol associated with DRCH and LRCH; The modulation symbols are extracted from the subcarriers, demodulated and decoded to recover the data. 23. The method according to claim 22, wherein in the one transmission frame, the number of subcarriers constituting the DRCH on each OFDM symbol is the same and fixed. 24. The method according to claim 23, characterized in that the sub-carrier intervals constituting the DRCH on each OFDM symbol are distributed over the entire frequency domain. 25. The method according to claim 24, characterized in that the subcarriers constituting the DRCH on each OFDM symbol are equally spaced across the entire frequency domain. 26. The method according to claim 25, wherein in each subband formed by multiple consecutive subcarriers, the number of subcarriers occupied by the DRCH is the same. 27. The method according to any one of claims 22 to 26, characterized in that, on different OFDM symbols, frequency hopping of subcarriers constituting the DRCH occurs. 28. The method of claim 27, wherein the frequency hopping pattern is generated by a frequency hopping sequence. 29. The method according to claim 27, wherein the number of subcarriers included in the LRCH is greater than or equal to the number of subcarriers included in the DRCH, and is an integer multiple of the number of subcarriers included in the DRCH. 30. A launcher, characterized in that it comprises: It is used to distinguish the data of different users into suitable for DRCH transmission and suitable for LRCH transmission. According to the amount of data that DRCH and LRCH need to transmit in the current frame, select the corresponding multiplexing mode, and associate the user data that needs to be transmitted with the corresponding resource channel. , the resource channel includes a discrete resource channel DRCH composed of a fixed number of subcarriers scattered on each OFDM symbol in a transmission frame, and a unit of a centralized resource channel LRCH composed of the remaining subcarriers in the frame , wherein the ratio of the number of subcarriers of DRCH and LRCH contained in each transmission frame in different multiplexing modes is different; Encoding and modulating the data to generate a modulation symbol, and mapping to a unit on a subcarrier of a corresponding OFDM symbol; A unit that performs inverse fast Fourier transform processing on subcarriers and transmits OFDM symbols. 31. The transmitting device according to claim 30, wherein in the one transmission frame, the number of subcarriers constituting the DRCH on each OFDM symbol is the same and fixed. 32. The transmitting device according to claim 31, characterized in that, the spacing of the subcarriers constituting the DRCH on each OFDM symbol is distributed over the entire frequency domain. 33. The transmitting device according to claim 32, wherein the subcarriers constituting the DRCH on each OFDM symbol are equally spaced across the entire frequency domain. 34. The transmitting device according to claim 33, wherein in each subband formed by a plurality of consecutive subcarriers, the number of subcarriers occupied by the DRCH is the same. 35. The transmitting device according to any one of claims 30 to 34, characterized in that, on different OFDM symbols, frequency hopping of subcarriers constituting the DRCH occurs. 36. The transmitting device according to claim 35, wherein the number of subcarriers included in the LRCH is greater than or equal to the number of subcarriers included in the DRCH, and is an integer multiple of the number of subcarriers included in the DRCH. 37. A receiving device, comprising: It is used to receive the OFDM symbols of the data frame and obtain the control information of the resource channel from the control channel, which consists of a fixed number of subcarriers scattered on each OFDM symbol in a transmission frame Discrete resource channel DRCH, and the unit of centralized resource channel LRCH composed of the remaining subcarriers in the frame, where the ratio of the number of subcarriers of DRCH and LRCH contained in each transmission frame in different multiplexing modes is different, and different transmission according to needs The user data is suitable for DRCH transmission and LRCH transmission, and according to the size of the data volume that DRCH and LRCH need to transmit in the current frame, select the corresponding multiplexing mode; A unit for performing fast Fourier transform on the OFDM code to recover the subcarriers on each OFDM symbol associated with the DRCH and LRCH; A unit for extracting modulation symbols from subcarriers, demodulating and decoding the modulation symbols to recover data. 38. The receiving device according to claim 37, wherein in the one transmission frame, the number of subcarriers constituting the DRCH on each OFDM symbol is the same and fixed. 39. The receiving device according to claim 38, characterized in that the spacing of subcarriers constituting DRCH on each OFDM symbol is distributed over the entire frequency domain. 40. The receiving device according to claim 39, wherein the subcarriers constituting the DRCH on each OFDM symbol are equally spaced across the entire frequency domain. 41. The receiving apparatus according to claim 40, characterized in that, in each subband formed by multiple consecutive subcarriers, the number of subcarriers occupied by the DRCH is the same. 42. The receiving device according to any one of claims 37 to 41, characterized in that, on different OFDM symbols, frequency hopping of the subcarriers constituting the DRCH occurs. 43. The receiving device according to claim 42, wherein the number of subcarriers included in the LRCH is greater than or equal to the number of subcarriers included in the DRCH, and is an integer multiple of the number of subcarriers included in the DRCH.

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