CN1992575A - Method of link adaptation for CDMA communications system and realization apparatus thereof - Google Patents
Method of link adaptation for CDMA communications system and realization apparatus thereof Download PDFInfo
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Abstract
This invention provides a link adaptive method and equipment used in the CDMA communication system. The base station/terminal unilateral detects the channel quality, and changes data packets coding modulation configuration and load-carrying data code group. The notification process of changing coding modulation configuration and load-carrying data code group can simply insert corresponding configuration mode indication value into the current transmission data packets, and then sent to the other side. The determination of data packets coding modulation configuration and load-carrying data code group depends on the two-dimensional space composes by SINR and multi-path complexity. The invention solves the problem that the transmission control signal and measurement report occupies channel resources, to make up for the problem that for improving system data throughput in LAS-CDMA wireless communication system, the single SINR is not enough to be the determination condition to change the coding modulation configuration mode.
Description
Technical Field
The invention relates to a link self-adapting method suitable for a CDMA (code division multiple access) communication system, also relates to key equipment for realizing the method, and belongs to the technical field of mobile communication.
Background
In mobile communication, multipath interference signals will cause severe amplitude fading and delay spread of received signals, resulting in degraded error performance. An effective method for overcoming amplitude fading is to increase the transmission power and fully reserve margin. This approach can achieve better transmission performance under poor channel conditions, but causes resource waste under better channel conditions. Another approach is to trade off the spectrum utilization of the wireless channel for system transmission performance. But this will reduce the capacity of the system when the channel conditions are good. Neither of these two deficiencies (wasted resources and reduced system capacity) is desirable for system designers to obtain as high a data transmission rate as possible over a limited channel bandwidth, even if the system's spectrum utilization is optimized.
The link adaptation technology is provided for the requirement, and has strong advantages in reducing resource waste and improving the utilization rate of the channel spectrum. The existing adaptive coded modulation (AMC), automatic repeat request (ARQ), hybrid repeat feedback (HARQ), fast scheduling, fast power control, etc. all belong to the link adaptation technology category. The link adaptive technology has the advantages that the spectrum utilization rate of the system can be improved and the influence of the channel environment change on the spectrum utilization rate of the system can be reduced under the principle of maintaining different service QoS requirements.
The basic idea of adaptive coded modulation is to change the modulation scheme and coding format to adapt to the channel conditions. In the case of good channel quality, communicating with an MCS (coded modulation scheme) having a higher signaling rate; and in case of poor channel quality, communicating with MCS having lower signaling rate. SINR (signal to interference ratio) can effectively reflect channel quality, and therefore, in many wireless communication systems with AMC configuration (HSDPA, HIPERLAN, 802.11a, 802.16, etc.), it is used as a basis for MCS change. When the SNIR is higher than a certain threshold, selecting the MCS with high signaling rate; when the SNIR is below a certain threshold, a low signaling rate MCS is selected. Adaptive coded modulation can effectively reduce the interference level of a cellular system under the condition of not adjusting the transmission power by adjusting a modulation mode and a coding format, so the adaptive coded modulation is widely adopted in wireless data transmission systems such as GPRS, EDGE, HSDPA, WCDMA, CDMA2000, EVDO, HIPERLAN, 802.11a, 802.16 and the like.
In the adaptive coded modulation method, in order to enable a receiver to correctly demodulate a current received symbol, a change notification needs to be sent to the receiver and the changed MCS needs to be transmitted every time a transmitter changes the MCS, so that the number of control amounts of transmission signaling is increased, and limited band resources are occupied.
In a patent application No. 02107877.7 entitled "adaptive modulation method and radio controlled and mobile communication system", a method for reducing the number of control signaling transmissions is disclosed. The method is suitable for TDMA (time division multiple access) wireless communication systems, and the main idea is to make each time slot in a frame correspond to a modulation mode one by one. In this way, the transmitting side can process the received signal according to the modulation scheme by only transmitting the modulation scheme of each time slot in the frame to the receiving side in advance. The configuration situation of the modulation mode is only sent to the receiving side once by the sending side, so that the quantity of the control signaling can be reduced. However, there is a problem that the modulation scheme of each time slot in a frame is relatively fixed, and the modulation scheme cannot be completely and effectively adaptive to channel variation.
In a patent application No. 200510059500.3 entitled "wireless communication method and wireless apparatus using adaptive modulation scheme", an AMC implementation method satisfying TDD (time division duplex) and FDD (frequency division duplex) usage is disclosed. The method opens up a measurement report used by an upper special control channel for bearing in the frame structure design, and effectively realizes the AMC of an uplink and a downlink. The advantage of this approach is also its disadvantage, namely the need to open up control channels dedicated to carrying measurement reports, thereby reducing the throughput of the system data.
The LAS-CDMA system is proposed by the li dawn teaching, and has as its core the use of LS sequences and LA sequences with zero interference windows. The function of the LS sequence is the same as the Walsh sequence in CDMA 2000; the function of the LA sequence is the same as the PN sequence in CDMA 2000. By zero interference window is meant that the autocorrelation function of the code sequence is ideal, the cross correlation function is also ideal over a range, and the interference side-peaks appear at a fixed phase offset.
Fig. 1 and 2 show the basic features of the LS sequence. The LS sequences are orthogonal complementary sequences and have zero interference windows. By zero interference window is meant that the autocorrelation function of the code sequence is ideal, the cross correlation function is also ideal over a range, and the interference side-peaks appear at a fixed phase offset. Fig. 1 shows the autocorrelation and cross-correlation function characteristic curves of LS sequences. The pair of sub-peak intervals closest to the origin are referred to as zero interference windows (denoted by IFW), and the sub-peak positions are referred to as mullions. It can be seen that all multipath signals falling within the zero interference window will not generate interference; multipath signals falling at the mullion positions can cause interference. The LS sequence is a channel spreading code of LAS-CDMA, and functions the same as the Walsh sequence in CDMA 2000. Due to the existence of IFW in the LS sequence, the LS sequence has strong inhibition capability on multipath signals, the inhibition capability on the multipath signals is different due to different IFW sizes, and the inhibition capability on the multipath signals is stronger for code groups with larger IFW. Fig. 2 shows a distribution rule of the sizes of zero interference windows between LS sequences with a code length of 64Chips in a synthesis mode, where IFW-4 indicates that the zero interference window is (-3, 3) Chips; IFW-8 denotes the sequence cross-correlation zero-interference window of (-7, 7) chips. As can be seen, the LS sequence has a grouping property in use. The IFW of the cross-correlation property of any two LS sequences in the group is larger than that of the cross-correlation property of two LS sequences in the group. The larger the IFW between LS sequences within a code group, the greater the resistance to multipath interference using such a code group, but the fewer the number of LS sequences in such a code group.
In a CDMA wireless communication system using a PN code as a channel spreading code, SINR alone can be used as a determination condition for changing MCS, but in an LAS-CDMA wireless communication system using an LS code as a channel spreading code, SINR alone is insufficient as a determination condition for changing MCS in order to improve system throughput.
Disclosure of Invention
The invention aims to provide a link self-adaption method for a CDMA communication system, which solves the problem that channel resources are occupied due to the transmission of control signaling and measurement reports, and makes up the problem that in an LAS-CDMA wireless communication system, in order to improve the system throughput, the single SINR is not enough to be used as a judgment condition for changing the MCS.
It is a further object of the invention to provide a wireless communication device for implementing the method.
Therefore, the invention adopts the following technical scheme:
a link adaptation method for a CDMA communication system, characterized in that:
at a sending end, a receiving party is informed of the code modulation configuration of a current data packet and a code group used by a bearer service by inserting an indicated value into the data packet;
at the receiving end, firstly, the judgment is carried out according to the indicated value, and the information of the data packet is determined according to the indicated value, so as to guide other processing work of the data packet.
Wherein,
the service channel bearing the indicated value is a fixed code channel, and during transmission, the indicated value is located at a fixed position of a data frame and adopts a low-order modulation mode.
The traffic channel code is a spreading sequence with a zero interference window or a low correlation window.
And determining the code modulation configuration of the current data packet and the code group used by the bearer service according to the position of the current channel environment in a two-dimensional space formed by the SINR and the multipath complexity.
At the transmitting end, the processing mode of the indicated value and the coding modulation mode of the current data packet are mutually independent.
The channel quality and the channel multipath profile are measured by the base station/terminal and the coded modulation configuration of the data packets and the code groups used for the bearer service are altered accordingly.
And measuring the multipath distribution of a downlink based on a downlink synchronous channel, and measuring the channel quality based on a pilot channel.
Uplink multipath profile and channel quality are measured based on the pilot channel.
A wireless communication device for implementing a link adaptation method for a CDMA communication system, the device comprising a base station and a terminal, characterized in that:
the base station and the terminal comprise a sending part, a receiving part and a link self-adaptive control unit, wherein the sending part comprises a data dividing unit, a downlink multi-code channel service information processing unit, a downlink synchronous information processing unit, a first TDD frame control unit, a sending RF, a first transceiving conversion unit and a sending antenna; the receiving part comprises a receiving antenna, a second transceiving conversion unit, a receiving RF, a first TDD frame control unit, an uplink synchronous information processing unit, an uplink multi-code channel service information processing unit and a data merging unit.
A wireless communication device for implementing a link adaptation method for a CDMA communication system, the device comprising a base station and a terminal, characterized in that:
the base station and the terminal comprise a sending part, a receiving part and a link self-adaptive control unit, wherein the sending part comprises a data segmentation unit, a downlink multi-code channel service information processing unit, a downlink synchronous information processing unit, a framing unit, a sending RF, a first shared device and a sending antenna; the receiving part comprises a receiving antenna, a second shared device, a receiving RF, a frame decoding unit, an uplink synchronous information processing unit, an uplink multi-code channel service information processing unit and a data merging unit.
The method and the device thereof improve the system throughput based on the self-adaptive code modulation and the dynamic adjustment of the number of the service channel spread spectrum code channels and the code group. The method is suitable for CDMA wireless communication system, and the system working mode can be TDD or FDD. The link self-adaptive method provided by the invention can avoid occupying channel overhead due to sending of the control signaling and the measurement report, and improves the data throughput of the system.
Drawings
FIG. 1 is a cross-correlation characteristic curve of the LS sequence, wherein the range of the interval corresponding to IFW is shown;
FIG. 2 is a distribution rule of sizes of zero interference windows among LS sequences with a code length of 64Chips in a synthesis mode;
FIG. 3 is a table of link parameter configurations embodying the present invention;
FIG. 4 is a two-dimensional coordinate system established in the practice of the present invention;
fig. 5 is a flowchart of the operation of selecting a code modulation configuration and code group to implement the present invention;
fig. 6 is a flow chart of multi-code channel service data processing at a base station/terminal sending end;
fig. 7 is a flow chart of base station/terminal signal processing for implementing the present invention in TDD mode of operation;
FIG. 8 is a timing diagram of the operation of the system shown in FIG. 7;
fig. 9 is a flow chart of base station/terminal signal processing for implementing the present invention in FDD mode of operation;
FIG. 10 is a timing diagram for the operation of the system shown in FIG. 9;
Detailed Description
As described above, the present invention is a link adaptation method for improving the throughput of a CDMA wireless communication system by adaptively code-modulating and dynamically allocating the number of spreading codes and code groups of a traffic channel according to multipath distribution in a channel environment. The method is suitable for all CDMA wireless communication systems including LAS-CDMA, TD-SCDMA and the like, and the working mode of the system can be TDD or FDD. The provided link self-adaptive method can avoid occupying channel overhead due to sending control signaling and measurement report, and improve system data throughput.
The realization idea of the invention is as follows: if we can measure the multipath distribution in the current channel, we can select the LS code group in accordance with the condition, and realize the link adaptation that the number of the spread spectrum code channels of the service channel and the code group change along with the channel change. Determining the multipath profile of a channel is possible in CDMA systems where the finger delays of the RAKE receiver vary as the relative delays of the multipath signal and the main path signal vary. When the channel environment does not have multipath signals, the link self-adaptive control module selects an LS code group with IFW being 1; when a multipath signal exists in a channel environment, the link adaptation control module selects an LS code group having a larger IFW. Obviously, under the same MCS, the larger the data packet carried by more code channels, the higher the signaling rate of the system.
Therefore, as shown in fig. 3, the selection of the MCS of the system is performed based on the table shown in fig. 3, and after one MCS is selected, the transmitting end needs to insert an Indicator (Indicator) value corresponding to the MCS into a specific position of the current packet and transmit the value to the receiving end. The MCS is changed based on the SINR of the currently received signal. For example, see FIG. 3, when V1≤SINR＜V2When the data packet is received, the link self-adaptive control module selects MCS (2) as a coding configuration mode of the current data packet, and simultaneously, the value of 2 is modulated and inserted into a specific position of the current data packet to be sent to a receiving party; when SINR < V1And then, the link self-adaptive control module selects MCS (1), and inserts the value of 1 into the specific position of the current data packet and sends the data packet to the receiving party.
The MCS configuration in fig. 3 includes factors such as coding efficiency, coding scheme, interleaving scheme, modulation scheme, and spreading factor. Changes in any one factor may result in changes in the MCS, and thus the MCS may be configured in a large number of ways. For example, in terms of coding efficiency and modulation scheme, if the coding efficiency of the system design includes 1/2, 2/3 and 3/4; the modulation schemes include BPSK, QPSK, 16QAM, and 64QAM, and 12 MCSs can be combined. Considering the influence of the coding scheme and the spreading factor, the obtained MCS is increased. Actually, the MCS in fig. 3 is selected from the above-mentioned multiple configurations according to the fact that the system throughput is the largest under the same SINR condition, and the SINR threshold interval corresponding to two adjacent MCSs needs to be greater than or equal to the estimation accuracy of the SINR algorithm.
For clarity, in the embodiment shown in fig. 3, only the correspondence of Indicator values to MCSs is given. In addition, in order to reduce the transmission of control parameters, in implementing the present invention, the change of Indicator value includes 2 parameters, one is the change of MCS and the other is the change of code group used by the bearer service.
Fig. 4 is a two-dimensional coordinate established in practicing the present invention, with the abscissa representing the SINR of the received signal and the ordinate representing the complexity of the multipath profile in the channel. The multipath distribution complexity refers to the IFW size among LS code groups meeting the multipath environment, wherein the larger the IFW is, the higher the multipath environment complexity is, and the smaller the IFW is, the smaller the multipath environment complexity is. The larger the IFW, the stronger the resistance to multipath interference using such code groups. Therefore, LS code blocks can be dynamically selected by measuring the multipath distribution of the channel, and link adaptation of the LS code blocks changing along with the multipath change of the channel is realized. The code allocation manner of any row corresponding to the ordinate in fig. 4 is determined in fig. 3, and the corresponding MCS is the same for different LS code groups. Fig. 5 is a flowchart of the operation of determining the code modulation scheme and the code group based on fig. 3 and 4. The work shown in fig. 5 is performed in the link adaptation control unit in the example shown in fig. 7 and 9. Referring to fig. 5, the link adaptive control unit first determines in 501 whether the current multipath distribution meets O-a 1, if yes, jumps to 502, and selects a corresponding LS code group; if not, jumping to 511, and proceeding in sequence. Once the LS code group is selected, the MCS needs to be determined next. 503 gives a specific procedure for determining the MCS, which is determined according to the SINR value. 513. The expansion of 516 and 518 is identical to the flow shown at 503.
Fig. 6 is a flow chart of multi-code channel service data processing at a transmitting end of a base station/terminal. The data dividing unit 601 divides the transmission data packet according to the number of traffic channels required by the link adaptive control unit, and the divided data is sent to units 602, 611, 616, and the like for CRC processing. For simplicity, a single signal processing is described as an example. The input data is added with CRC 602 and then sent to channel coding 603. 603 performs coding processing on the transmission data according to the requirement of the link adaptive control unit, sends the result to an interlace 604, and sends the interlaced data to a modulation map 605. 605 modulates the transmission data according to the request of the link adaptive control unit, and the modulated data is sent to 606. 606 inserts the modulated Indicator value in front of the 605 data to form a new packet, which is sent to channel code spreading 607. 607 performs spreading on the data sent from 606 according to the assigned spreading factor and LS channel code and sends the result to code channel combining 621. 621 performs chip-level summation of all traffic channel data and sends the results to TDD frame control 704 and TDD frame control 804 shown in fig. 7, framing 904 and framing 1004 shown in fig. 9. In order to ensure the reliability of transmission of the Indicator value, the coding mode of the Indicator value is different from the coding mode of the transmission data packet, and low-order modulation, such as BPSK modulation or QPSK modulation, is separately performed in the modulation map 609.
Fig. 7 is a block diagram of a signal processing structure of embodiment 1 of a wireless communication system to which the present invention is applied. The system comprises a base station 700 and a terminal 800, and realizes bidirectional communication by utilizing an uplink and a downlink, and the working mode of the system is TDD. Since each terminal 800 has the same configuration, only a signal processing flowchart of 1 base station and 1 terminal is shown in fig. 7.
The base station 700 includes a transmission system, a reception system, and a link adaptation control unit 3 section. Briefly, the transmitting part comprises data segmentation 701, downlink multi-channel service information processing 702, downlink synchronization information processing 703, TDD frame control 704, transmitting RF705, transceiving conversion 706, and transmitting antenna 707; the receiving part comprises a receiving antenna 707, a transceiving conversion 706, a receiving RF708, a TDD frame control 704, an uplink synchronization information processing 709, an uplink multi-channel service information processing unit 710, and a data combination 711.
The base station signal processing flow is illustrated as follows:
at the transmitting end, the data segmentation 701 segments the transmission data to the corresponding service code channels according to the output of the link adaptive control unit, so as to perform data processing. The development of the downlink multi-code channel service information processing unit 702 is the service information processing process shown in fig. 6, which includes several links of CRC, channel coding, interleaving, modulation mapping, spreading and code channel synthesis. The service data after the encoding and spreading processing is inserted into the downstream synchronization information processing 703, and the specific position of the insertion is determined by the frame structure shown in fig. 8, that is, the downstream synchronization information processing module 703 outputs data occupying the Dssf position in the frame structure; the downlink multi-code channel service information processing module 702 outputs the position occupying the frame structure DL-DATA. The downlink synchronization information processing module 703 mainly completes generation of a downlink synchronization signal. The terminal can complete the work of starting up search, cell selection, frame boundary detection and the like by using the synchronous signal. The TDD frame control module 704 completes framing processing of the downlink synchronization information data 703 and the downlink service information data 702, and the framed data is sent to the transmission RF705 processing module. The transmit RF705 has the effect of frequency conversion and power amplification. The transmit RF705 carrier modulates the framed signal sent at 704 to convert the frequency to the radio frequency used by the downlink air interface. While amplifying the signal to a predetermined transmission power. The amplified signal is transmitted to a transmission antenna 707 through a transmission/reception conversion 706, and is transmitted to the terminal 800.
At the receiving end, the receiving antenna 707 amplifies the uplink signal with low noise and sends the amplified uplink signal to the receiving processing module RF708 via the transceiving converter 706. RF708 has amplification and frequency translation functions that frequency translate the signal from 706 to the frequency required by the system intermediate frequency or baseband, while amplifying the signal to the system's desired interface level. The TDD frame control module 704 divides the received RF708 DATA into uplink synchronization DATA field Ussf and uplink service DATA field UL-DATA according to the framing rule shown in fig. 8, and simultaneously sends Ussf to the uplink synchronization information processing unit 709 and UL-DATA to the uplink multi-channel service information processing unit 710. The uplink synchronization information processing unit 709 mainly processes the Ussf, and determines whether a terminal sends an uplink synchronization request. If there is an uplink synchronization request sent by the terminal, the uplink synchronization processing module 709 calculates the power of the uplink synchronization signal of the terminal when it reaches the base station and the distance between the terminal and the base station, and sends the parameter to the downlink to the terminal in a message manner, so as to complete the uplink synchronization processing of the terminal. The uplink multi-code channel service information processing module 710 completes the operations of despreading the uplink service information, channel estimation and compensation, symbol soft and hard decision, channel decoding, deinterleaving, CRC decoding, and the like. In order to improve the working performance of the system, the 710 module can adopt a RAKE receiving mode to process the service information. Because the data packet sent by the terminal contains the MCS configuration of the data packet and the Indicator value corresponding to the configuration is inserted at the fixed symbol position of the fixed code channel, the base station can correctly and effectively decode the data packet. It should be noted that the decision, channel decoding, deinterleaving, and other operations of the Indicator value and other information symbols in the data packet are performed separately, and the base station first performs the decision operation on the Indicator value to obtain the Indicator value so as to guide the normal operations of the decision, channel decoding, deinterleaving, and other operations of other symbols in the data packet. In addition to correctly interpreting the uplink service data packet, the base station also extracts the current channel quality and multipath profile from the uplink signal. This is done by the link adaptation control unit 712. The link adaptive control unit 712 includes a channel quality monitoring module, a multipath distribution monitoring module, and a link parameter configuration control module. The channel quality monitoring module completes the measurement of the channel quality. There are many ways to understand the description of the channel quality, such as how much the system is affected by interference, how much the signal propagation loss is, etc. When the signal propagation loss is small, the Received Signal Strength (RSSI) is high, which is called that the channel quality is good; when the signal is less affected by interference and the received signal to interference and noise ratio (SINR) is greater, it is also called that the channel quality is good. It should be noted that the present invention uses SINR as a measure of channel quality, but does not exclude using RSSI to measure channel quality. The output of the channel quality monitoring module is directly provided to the link parameter configuration control module. The multi-path distribution monitoring module completes the measurement of the channel multi-path components and the mutual phase time delay, and the measurement result is also directly sent to the link parameter configuration control module. The link parameter configuration control module selects the MCS and code group satisfying the channel condition from the 2 entry parameters according to the procedure shown in fig. 5 to provide for the next downlink DL-DATA, as shown in fig. 8.
The signal processing flow of the terminal is equivalent to that of the base station, and is described as follows:
at the transmitting end, the data division 801 divides the transmission data according to the requirement of the link adaptive control unit 812, and sends the divided data to the uplink multi-code channel service information processing unit 802, and the processing of the work of CRC, channel coding, interleaving, modulation mapping, spreading, code channel synthesis, and the like of the data packet is completed by the uplink multi-code channel service information processing unit 802. The development of the uplink multi-code channel service information processing unit 802 is a processing structure shown in fig. 6. 802 sends the service data after the encoding and spreading process to a TDD frame control unit 804. The uplink synchronization processing module 803 mainly completes generation of an uplink synchronization signal. When the terminal needs to communicate with the base station, the terminal needs to send the uplink synchronization signal to the base station, the base station receives the synchronization signal, measures the power of the signal and the distance between the base station and the terminal, and informs the terminal through a message, and the terminal performs power control and synchronization adjustment based on the information. 803 is also sent to the TDD frame control module 804. The TDD frame control module 804 completes framing processing on the data of the uplink synchronization information processing unit 803 and the data of the uplink service information processing unit 802. Specifically, according to the frame control signal, the DATA output by the uplink synchronization information processing module 803 is placed at the Ussf position in the frame structure shown in fig. 8, and the output of the uplink multi-channel service information processing module 802 is placed at the UL-DATA position in the frame structure shown in fig. 8. The framed data is sent to the transmit RF805 processing module. The transmission RF805 has the functions of frequency conversion and power amplification. The transmission RF805 carrier-modulates the framed signal transmitted from the transmission RF 804 and converts the carrier-modulated framed signal into a radio frequency used by the air interface of the downlink. While amplifying the signal to a predetermined transmission power. The amplified signal is sent to a transmission antenna 807 through a transmission/reception conversion 806, and is transmitted to the base station 700.
At the receiving end, the downlink signal is amplified by the receiving antenna 807 with low noise and then sent to the receiving RF808 processing module via the transceiving conversion 806. The receive RF808 has the functions of amplification and frequency translation that frequency translates the signal to 806 to the system intermediate frequency or frequency required by the baseband while amplifying the signal to the system's desired interface level. The TDD frame control module 804 divides the DATA result of the received RF808 into two parts, namely a downlink synchronization DATA field Dssf and a downlink service DATA field DL-DATA according to the framing rule shown in fig. 8, and simultaneously sends Dssf to the downlink synchronization information processing unit 809 and DL-DATA to the downlink multi-channel service information processing unit 810. The downlink synchronization information processing unit 809 mainly processes Dssf to complete operations such as power-on detection, frame boundary detection, cell search, multipath search, carrier capture, and the like. The downlink multi-code channel service information processing module 810 completes the operations of despreading downlink service information, channel estimation and compensation, symbol soft and hard decision, channel decoding, deinterleaving, CRC decoding, and the like. In order to improve the working performance of the system, the 810 module can adopt a RAKE receiving mode to process the service information. Because the data packet sent by the base station contains the MCS configuration of the data packet and the Indicator value corresponding to the configuration is inserted at the position of the fixed code channel fixed symbol, the terminal separately processes the decision, channel decoding, de-interleaving and other work of the Indicator value and other information symbols in the data packet. The terminal firstly judges the Indicator value to obtain the Indicator value; and then guiding the work of judging other symbols in the data packet, decoding the channel, deinterleaving and the like according to the extracted Indicator value. The terminal needs to extract the current channel quality and the multipath distribution of the channel from the downlink signal in addition to correctly interpreting the downlink service data packet and the downlink synchronization information. This is done by the link adaptation control unit 812. The link adaptive control unit 812 includes a channel quality monitoring module, a multipath distribution monitoring module, and a link parameter configuration control module. The channel quality monitoring module completes the measurement of the channel quality. The output of the channel quality monitoring module is directly provided to the link parameter configuration control module. The multi-path distribution monitoring module completes the measurement of the channel multi-path components and the mutual phase time delay, and the measurement result is also directly sent to the link parameter configuration control module. The link parameter configuration control module selects the MCS and code group satisfying the channel condition according to the procedure shown in fig. 5 for the next downlink UL-DATA, as shown in fig. 8.
Fig. 9 is a block diagram of a signal processing structure of embodiment 2 of a wireless communication system to which the present invention is applied. The system comprises a base station 900 and a terminal 1000, and realizes bidirectional communication by using uplink and downlink, and the working mode of the system is FDD. Since each terminal 1000 has the same configuration, only a signal processing flowchart of 1 base station and 1 terminal is shown in fig. 9. The signal processing flow of the base station 900 is as follows:
at the transmitting end, the data segmentation 901 segments the transmission data onto the traffic channels configured 913 for data processing according to the configuration result of the link adaptive control unit 913. The development of the downlink multi-code channel service information processing unit 902 is the service information processing process shown in fig. 6, which includes several links of CRC, channel coding, interleaving, modulation mapping, spreading and code channel synthesis. 902 sends the output result to framing 904, 904 inserts 902 the output DATA in the DL-DATA field according to the frame structure shown in fig. 10. The downlink synchronization information processing module 903 mainly completes generation of a downlink synchronization signal. The terminal can complete the work of starting up search, cell selection, frame boundary detection and the like by using the synchronous signal. 903 sends the output to framing 904, 904 inserts 902 the output data in the Dssf field according to the frame structure shown in figure 10. The framed data is sent 904 directly to transmit RF 905. The transmit RF905 has the functions of frequency conversion and power amplification. The transmission RF905 carrier-modulates the framed signal transmitted at 904 and converts the carrier-modulated framed signal into a radio frequency used by the air interface of the downlink. While amplifying the signal to a predetermined transmission power. The amplified signal is sent to transmission antenna 907 via duplexer 906, and is transmitted to terminal 1000.
At the receiving end, the uplink signal is amplified by the receive antenna 907 with low noise and then sent to the receive RF908 processing module via the duplexer 906. Receive RF908 has the functions of amplification and frequency translation that it frequency translates the signal to 906 to the system intermediate frequency or frequency required by baseband while amplifying the signal to the system's desired interface level. The deframing 909 divides the DATA result of the received RF908 into two parts, i.e., an uplink synchronization DATA field Ussf and an uplink service DATA field UL-DATA according to the framing rule shown in the uplink UL in fig. 10, and simultaneously sends Ussf to the uplink synchronization information processing unit 910 and UL-DATA to the uplink multi-channel service information processing unit 911. The uplink synchronization information processing unit 910 mainly processes Ussf and determines whether there is a terminal sending an uplink synchronization request. If there is an uplink synchronization request sent by the terminal, the uplink synchronization processing module 910 calculates the power of the uplink synchronization signal of the terminal when it reaches the base station and the distance between the terminal and the base station, and sends the parameter to the downlink to the terminal in a message manner, so as to complete the uplink synchronization processing of the terminal. The uplink multi-code channel service information processing module 911 completes the operations of despreading the uplink service information, channel estimation and compensation, symbol soft and hard decision, channel decoding, deinterleaving, CRC decoding, and the like. In order to improve the working performance of the system, the 911 module can adopt a RAKE receiving mode to process the service information. Because the data packet sent by the terminal contains the MCS configuration of the data packet and the Indicator value corresponding to the configuration is inserted at the fixed symbol position of the fixed code channel, the base station can correctly and effectively decode the data packet. It should be noted that the decision, channel decoding, deinterleaving, and other operations of the Indicator value and other information symbols in the data packet are performed separately, and the base station first performs the decision operation on the Indicator value to obtain the Indicator value so as to guide the normal operations of the decision, channel decoding, deinterleaving, and other operations of other symbols in the data packet. In addition to correctly interpreting the uplink service data packet, the base station also needs to extract the current channel quality and the multipath profile of the channel from the uplink signal. This is done by the link adaptation control unit 913. 913 includes a channel quality monitoring module, a multipath distribution monitoring module and a link parameter configuration control module. The channel quality monitoring module completes the measurement of the channel quality. There are many ways to understand the description of the channel quality, such as how much the system is affected by interference, how much the signal propagation loss is, etc. When the signal propagation loss is small, the Received Signal Strength (RSSI) is high, which is called that the channel quality is good; when the signal is less affected by interference and the received signal to interference and noise ratio (SINR) is greater, it is also called that the channel quality is good. The output of the channel quality monitoring module is directly provided to the link parameter configuration control module. The multi-path distribution monitoring module completes the measurement of the channel multi-path components and the mutual phase time delay, and the measurement result is also directly sent to the link parameter configuration control module. The link parameter configuration control module selects the MCS and code group satisfying the channel condition according to the procedure shown in fig. 5 for the next downlink DL-DATA, as shown in fig. 10.
The signal processing flow of the terminal is equivalent to that of the base station, and is described as follows:
at the transmitting end, data division 1001 divides transmission data into 1013 configured traffic channels according to the configuration result of link adaptive control section 1013, and uplink multi-code traffic information processing section 1002 completes processing of CRC, channel coding, interleaving, modulation mapping, spreading, code channel synthesis, and the like of the divided data packets. The development of the uplink multi-code channel service information processing unit 1002 is the processing structure shown in fig. 6. 1002 sends the encoded spread traffic data to framing 1004. The uplink synchronization processing module 1003 mainly completes generation of an uplink synchronization signal. When the terminal needs to communicate with the base station, the terminal needs to send the uplink synchronization signal to the base station, the base station receives the synchronization signal, measures the power of the signal and the distance between the base station and the terminal, and informs the terminal through a message, and the terminal performs power control and synchronization adjustment based on the information. The output of 1003 is also fed into framing 1004. 1004 completes framing processing of the data of the uplink synchronization information processing unit 1003 and the data of the uplink traffic information processing unit 1002 according to the UL frame structure shown in fig. 10. Specifically, the output of the uplink synchronization information processing module 1003 is placed at the Ussf position in the frame structure shown in fig. 10, and the output of the uplink multi-channel service information processing module 1002 is placed at the UL-DATA position in the frame structure shown in fig. 10. The framed data is sent to the transmit RF1005 processing module. The transmission RF1005 has the functions of frequency conversion and power amplification. The transmission RF1005 carrier-modulates the framing signal transmitted from the transmitter 1004 and converts the carrier frequency to a radio frequency used by the air interface of the downlink. While amplifying the signal to a predetermined transmission power. The amplified signal is sent to a transmission antenna 1007 via a duplexer 1006, and is transmitted to the base station 900.
At the receiving end, the receiving antenna 1007 amplifies the captured downlink signal with low noise, and then sends the amplified downlink signal to the RF1008 processing module through the duplexer 1006. The receive RF1008 has the functions of amplification and frequency translation that frequency translates the signal to 1006 to the system intermediate frequency or frequency required by the baseband while amplifying the signal to the system's desired interface level. The deframing unit 1009 divides the DATA result of the received RF1008 into two parts, namely a downlink synchronization DATA field Dssf and a downlink service DATA field DL-DATA according to the framing rule shown in the downlink DL of fig. 10, and simultaneously sends Dssf to the downlink synchronization information processing unit 1010 and DL-DATA to the downlink multi-channel service information processing unit 1011. The downlink synchronization information processing unit 1010 mainly processes Dssf to complete operations such as power-on detection, frame boundary detection, cell search, multipath search, carrier capture, and the like. The downlink multi-code channel service information processing module 1011 completes the operations of despreading downlink service information, channel estimation and compensation, symbol soft and hard decision, channel decoding, deinterleaving, CRC decoding and the like. In order to improve the working performance of the system, the 1011 module can adopt a RAKE receiving mode to process the service information. Because the data packet transmitted by the base station contains the MCS configuration of the data packet, and the Indicator value corresponding to the configuration is inserted at the fixed symbol position of the fixed code channel, the terminal should perform the operations of deciding, channel decoding, deinterleaving, and the like on the Indicator value and other information symbols in the data packet separately. The terminal firstly judges the Indicator value to obtain the Indicator value; and then, the normal operation of the judgment, channel decoding, de-interleaving and the like of other symbols in the data packet is guided according to the extracted Indicator value. The terminal needs to extract the current channel quality and the multipath distribution of the channel from the downlink signal in addition to correctly interpreting the downlink service data packet and the downlink synchronization information. This is done by the link adaptation control unit 1013. 1013 comprises a channel quality monitoring module, a multipath distribution monitoring module and a link parameter configuration control module. The channel quality monitoring module completes the measurement of the channel quality. The output of the channel quality monitoring module is directly provided to the link parameter configuration control module. The multi-path distribution monitoring module completes the measurement of the channel multi-path components and the mutual phase time delay, and the measurement result is also directly sent to the link parameter configuration control module. The link parameter configuration control module selects the MCS and code group satisfying the channel condition according to the procedure shown in fig. 5 for the next downlink UL-DATA, as shown in fig. 10.
Although the present invention has been described above by way of examples, a person of ordinary skill in the art will appreciate that there are numerous variations and modifications of the invention without departing from the spirit thereof, and it is intended that the appended claims encompass such variations and modifications.
Claims (10)
1. A link adaptation method for a CDMA communication system, characterized in that:
at a sending end, a receiving party is informed of the code modulation configuration of a current data packet and a code group used by a bearer service by inserting an indicated value into the data packet;
at the receiving end, firstly, the judgment is carried out according to the indicated value, and the information of the data packet is determined according to the indicated value, so as to guide other processing work of the data packet.
2. The link adaptation method for a CDMA communication system as claimed in claim 1, wherein:
the service channel bearing the indicated value is a fixed code channel, and during transmission, the indicated value is located at a fixed position of a data frame and adopts a low-order modulation mode.
3. The link adaptation method for a CDMA communication system as claimed in claim 1, wherein:
the traffic channel code is a spreading sequence with a zero interference window or a low correlation window.
4. The link adaptation method for a CDMA communication system as claimed in claim 1, wherein:
and determining the code modulation configuration of the current data packet and the code group used by the bearer service according to the position of the current channel environment in a two-dimensional space formed by the SINR and the multipath complexity.
5. The link adaptation method for a CDMA communication system as claimed in claim 1, wherein:
at the transmitting end, the processing mode of the indicated value and the coding modulation mode of the current data packet are mutually independent.
6. The link adaptation method for a CDMA communication system as claimed in claim 1, wherein:
the channel quality and the channel multipath profile are measured by the base station/terminal and the coded modulation configuration of the data packets and the code groups used for the bearer service are altered accordingly.
7. The link adaptation method for a CDMA communication system as claimed in claim 1, wherein:
and measuring the multipath distribution of a downlink based on a downlink synchronous channel, and measuring the channel quality based on a pilot channel.
8. The link adaptation method for a CDMA communication system as claimed in claim 1, wherein:
uplink multipath profile and channel quality are measured based on the pilot channel.
9. A wireless communication device for implementing a link adaptation method for a CDMA communication system, the device comprising a base station and a terminal, characterized in that:
the base station and the terminal comprise a sending part, a receiving part and a link self-adaptive control unit, wherein the sending part comprises a data dividing unit, a downlink multi-code channel service information processing unit, a downlink synchronous information processing unit, a first TDD frame control unit, a sending RF, a first transceiving conversion unit and a sending antenna; the receiving part comprises a receiving antenna, a second transceiving conversion unit, a receiving RF, a first TDD frame control unit, an uplink synchronous information processing unit, an uplink multi-code channel service information processing unit and a data merging unit.
10. A wireless communication device for implementing a link adaptation method for a CDMA communication system, the device comprising a base station and a terminal, characterized in that:
the base station and the terminal comprise a sending part, a receiving part and a link self-adaptive control unit, wherein the sending part comprises a data segmentation unit, a downlink multi-code channel service information processing unit, a downlink synchronous information processing unit, a framing unit, a sending RF, a first shared device and a sending antenna; the receiving part comprises a receiving antenna, a second shared device, a receiving RF, a frame decoding unit, an uplink synchronous information processing unit, an uplink multi-code channel service information processing unit and a data merging unit.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110506219A (en) * | 2017-03-15 | 2019-11-26 | 西格弗克斯公司 | The method and system of geo-location is carried out for the terminal to wireless communication system |
| CN110611553A (en) * | 2014-03-14 | 2019-12-24 | 三星电子株式会社 | Method and apparatus for encoding and decoding packets |
| US11665267B2 (en) | 2014-03-14 | 2023-05-30 | Samsung Electronics Co., Ltd. | Method and apparatus for encoding and decoding packet |
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2005
- 2005-12-31 CN CNA2005100488783A patent/CN1992575A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110611553A (en) * | 2014-03-14 | 2019-12-24 | 三星电子株式会社 | Method and apparatus for encoding and decoding packets |
| US11665267B2 (en) | 2014-03-14 | 2023-05-30 | Samsung Electronics Co., Ltd. | Method and apparatus for encoding and decoding packet |
| CN110506219A (en) * | 2017-03-15 | 2019-11-26 | 西格弗克斯公司 | The method and system of geo-location is carried out for the terminal to wireless communication system |
| CN110506219B (en) * | 2017-03-15 | 2023-09-12 | 西格弗克斯公司 | Method and system for geolocating a terminal of a wireless communication system |
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