CN1780242A

CN1780242A - Adaptive link realization

Info

Publication number: CN1780242A
Application number: CN 200410091253
Authority: CN
Inventors: 吴建军
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2004-11-17
Filing date: 2004-11-17
Publication date: 2006-05-31
Anticipated expiration: 2024-11-17
Also published as: CN100353722C

Abstract

The invention is in use for communication based on non-resource reservation protocol, and can measure quality message of channel occupied by itself at terminal. It includes: terminal receives system frame sent by base station; reads mode of code modulation of each burst recorded in system frame. With mode of code modulation of each burst, makes demodulation and decode for each burst; then makes transmission error rate statistics and measurement of signal quality for each data unit; according to result of transmission error rate statistics and measurement of signal quality, gets channel quality message of other corresponding channels; according to quality message of channel occupied by itself and quality message of other channels, makes self-adaptive adjustment for link.

Description

A kind of implementation method of link circuit self-adapting

Technical field

The present invention relates to the wireless access system technical field, be meant a kind of implementation method of link circuit self-adapting especially.

Background technology

IEEE 802.16 has defined the wireless metropolitan area network standard of broadband wireless access (BWA).This standard pin has defined different physical-layer techniques to different frequency range.The range of application of this standard is mainly towards dwelling house, small office/family office (SOHO), teleworker and the user of small enterprise (SME).

IEEE 802.16 media access control layers (MAC) are supported very disadvantageous user environment, can be applicable to be assigned on each channel hundreds and thousands of users' applied environment, support the business of continous way and burst type.IEEE 802.16 agreement MAC layers provide the support of link adaptation techniques, and corresponding term is the renewal of burst profile.The renewal system of referring to of Burst profile can be according to the channel variance situation of link, and different codings and modulation system that employing adapts, handle through this scheduling according to channel variation change code modulation mode, make system link satisfy under the situation of certain performance, more reasonably the resource of system is distributed.For example can be adjusted into and make it to have higher data rate, improve the throughput of wireless access with this to the user who sits pretty.

The general implementation of link adaptation techniques is at present: terminal is measured the current Traffic Channel of distributing to oneself, measure own channel conditions----and comprise parameters such as received signal to noise ratio, compare with certain certain threshold that preserved, that emulation provides, corresponding parameter again, be lower than or when being higher than certain certain threshold, then initiate the renewal process of burst profile, change the code modulation mode of this channel.

For emulation, itself be under certain channel model, under specific scene, and be under the prerequisite of assumed condition, to carry out.Be understood that the threshold value that emulation in any case drew also will inevitably there are differences with changeable actual conditions.Therefore, user terminal (SS, Subscribe Station) measures own channel and when adopting the mode of certain threshold to realize that the scheme of link circuit self-adapting is applied in the scene of reality, because described specified threshold can not be with the real-time change of actual sight, therefore, be difficult to the actual at that time channel situation of accurate basis and carry out the link circuit self-adapting adjustment, may cause the channel estimating mistake.Mistake to channel estimating may make system select wrong transfer of data data transfer rate and transmitted power again, and the waste power system capacity perhaps because of the too low frame error rate that increases system of power, the error rate occurs and raises.

Summary of the invention

In view of this, main purpose of the present invention is to provide a kind of implementation method of link circuit self-adapting, makes the link circuit self-adapting process according to carrying out the self adaptation adjustment as a reference with the actual state of other physical channels in the Frame, makes link circuit self-adapting more accurate.

The implementation method of link circuit self-adapting of the present invention is applied to the communication mode that non-resource is reserved, and terminal is measured the quality of channel information that oneself is communicated by letter and takies; This method is further comprising the steps of:

A, terminal are measured other quality of channel information;

B, carry out the adjustment of link circuit self-adapting according to the channel quality information that oneself takies and other channel quality informations measured.

Wherein, the step that the described terminal of steps A is measured other quality of channel information comprises: terminal receives the system-frame that the base station sends, and reads the code modulation mode of each resource section burst in this frame of putting down in writing in this system-frame; According to each burst code modulation mode that reads each burst in this system-frame is carried out demodulation coding; Each data cell that obtains behind the demodulation coding is carried out the measurement of transmission error rate statistics and signal quality respectively, draw other corresponding each channel quality informations according to error rate statistics and measurement result.

Wherein, described step of carrying out the transmission error rate statistics comprises: the value to the CRC CRC in the data unit is carried out CRC check; Transmit the positive false information of this data cell according to the check (CRC) outcome record; Repeat above step, obtain the positive false information of once above transmission data units, and error rate is added up.

Wherein, described error rate comprises: bit error rate BER, block error rate BLER, frame error rate FER.The measurement of described signal quality comprises: signal interference ratio SIR, year dried making an uproar than CINR or received signal intensity RSSI.

Wherein, this method further comprises: in the system-frame that the base station sent, arrange the burst order from low to high successively according to the code modulation mode required signal-to-noise ratio; Terminal judges when the transmission error rate that certain burst is measured is higher than certain set point when each burst carries out demodulation coding in to system-frame, ignores the statistics of the transmission error rate of the burst of this burst back of system-frame and the measurement of signal quality.

Wherein, the described step of carrying out the adjustment of link circuit self-adapting of step B comprises: the channel quality information that terminal takies oneself and other channel quality informations compare, whether judge under the terminal present located wireless link channel environment code modulation mode and the pairing Radio Resource of suitable other channels of use, if then ask the base station this terminal to be carried out the adjustment of link circuit self-adapting.

Wherein, step B further comprises: the channel quality information that terminal takies oneself and other channel quality information feedback are given the base station; The base station is adjusted the Radio Resource of distributing to each terminal according to whole all users' channel quality information and resource situation.

Wherein, channel refers to time interval resource, the frequency resource under the FDMA or the two dimension of the time slot frequency under the OFDMA resource under the TDMA.

By said method as can be seen, when the present invention adjusts at link circuit self-adapting, not only the data that receive oneself are carried out channel measurement, and receive other physic channel informations and measure and carry out the self adaptation adjustment as a reference, make self adaptation more meet the actual conditions of channel at that time, can more accurate realization link circuit self-adapting, thus the systematic function of making and system mode have more robustness.

And, owing to can measure other physic channel informations to compare, therefore terminal can compare according to each channel situation, and then learn the better code modulation mode that can adapt to oneself, and avoided the described mode that can only rely on the more own channel of emulation threshold value of background technology.

Terminal can be measured the quality situation of other channel resources under the current wireless channel circumstance in own current shared channel and the same frame thereof, and the various information that relate to Radio Link, and give the base station with these feedback information, the scheduling foundation of RRM is carried out in the base station according to these information.Make RRM more accurate.

Description of drawings

Fig. 1 is IEEE 802.16 system frame structure schematic diagrames.

Fig. 2 is IEEE 802.16 system TDD frame structure schematic diagrames.

Fig. 3 is the flow chart of link circuit self-adapting of the present invention.

Fig. 4 is for measuring the flow chart of each burst.

Embodiment

Fig. 1 shows IEEE 802.16 system frame structure schematic diagrames.Preamble field among the figure (Preamble) is used for realizing that downlink frame is synchronous; Frame control head field (FCH, Frame Control Header) is code modulation mode and the message-length that is used for indicating the broadcast part (Broadcast Msgs) of back, is used for terminal to the broadcast demodulation coding; Down link MAP message (DL_MAP) in the broadcast (Broadcast Msgs) and up link MAP message (UL_MAP) have defined downlink frame and code modulation mode of each resource section (burst) that each user distributed in the uplink frame and the shared Radio Resource after the broadcast (Broadcast Msgs) respectively, as timeslot number, number of subchannels etc.Resource section (burst) is a physical resource of distributing to the user in the system-frame, in a system-frame, and the corresponding burst of user, in TDMA, burst promptly is equivalent to distribute to user's time interval resource, because by burst transmission data, so burst also is equivalent to channel.

Certain SS is when receiving this system-frame, and first demodulation coding goes out the DL_MAP message in the Broadcast Msgs message, thereby can learn which burst is oneself in thereafter the downlink frame; Can also oneself upload burst in the employed uplink frame of data according to the UL_MAP message authentication.Owing in each system-frame, the employed burst of user is indicated, therefore, in transmission course, can change the employed burst of this user data of transmission easily by the Indication message of revising among the DL_MAP by DL_MAP.As can be seen, this mode does not need the base station for setting up certain channel (as time interval resource) in advance with user's communications, needn't use this channel (as time interval resource) to communicate in a communication process always yet, so be called the communication mode that non-resource is reserved.

In IEEE 802.16, by resource allocation conditions in DL_MAP and the UL_MAP message indication current wireless frame and the code modulation mode of each burst, this provides the foundation for the present invention program's realization among the Broadcast Msgs.Among the present invention, remove to learn occupation condition and the employed code modulation mode of this burst of each burst of downlink frame by DL_MAP message by SS, terminal pins is measured different burst and is decoded then, and will be used for link circuit self-adapting as a reference, and be different from the self adaptation of carrying out link in the background technology with the emulation threshold value as a reference to measurement result and the decoded result situation of other users' burst.SS also can feed back to the base station with metrical information simultaneously, carries out the reference frame of RRM and distribution as the base station unification.

In the air interface of IEEE 802.16, provide TDMA/FDMA/OFDMA several access modes.Be the implementation method that example illustrates link circuit self-adapting of the present invention in the TDMA mode below,, may further comprise the steps referring to Fig. 3:

Step 301: the base station issues the TDD system-frame, wherein this frame as shown in Figure 2, different terminal distribution has different burst, here promptly be presented as different time slots, and the DL_MAP message of the distribution condition of resource in this frame broadcast message (Broadcast Msgs) is put down in writing and is broadcasted, comprise which user which specific burst (time slot) has distributed to, and the link code modulation mode that each burst adopted etc.

Step 302: terminal receives this system-frame, learns code modulation mode in each burst by the DL_MAP message in the broadcast (Broadcast Msgs).

And, when radio frames issues, carry out scheduling of resource for the ease of realizing according to signal to noise ratio demand order from low to high, can be redefined for: in the air interface radio frames (TDD system-frame), arrange the burst order according to code modulation mode required signal-to-noise ratio order from low to high.If like this terminal measure and decoding in run into measurement result when very poor, just can ignore measurement to back burst because put in order according to the front is said, the needed demodulation signal to noise ratio of the burst of back is higher.

Step 303: terminal receives the burst of oneself from this system-frame, measure self radio quality of channel information, as FER, BER, BLER, SIR, CINR, RSSI etc.; Simultaneously, other burst is carried out demodulation coding, measure FER, BER, BLER, SIR, the channel quality informations such as CINR, RSSI of respective channel according to the code modulation mode of other burst that obtain.

SS is the same to the measuring process of other burst with measuring process to self shared burst, and why the present invention can do like this, is because terminal can be carried out demodulation coding or measure its information fully other burst.Unique different be since other burst by other CU, its upper layer data is encrypted, other user's of terminal there is no telling private key can not be resolved the packet on upper strata more.But irrelevant for Radio Link Management and the needed metrical information of link circuit self-adapting process and upper layer data, so terminal is through the processing of physical layer, promptly just can obtain desired parameters information and measure through the processing procedure of channel coding/decoding.

Being example with the measuring process to BLER below, the step of measuring each burst is further described, is example with the OFDM physical layer of IEEE 802.16, referring to Fig. 4, may further comprise the steps:

Step 3031: at first, terminal is according to defining and to the appointment of use code modulation mode, remove downlink data receiving at corresponding resource-area each burst of current wireless frame in the DL_MAP message;

Step 3032: then, through fast Fourier transformation algorithm (FFT) computing, carry out the OFDM demodulation, remove Cyclic Prefix in base band; Then, carry out demodulation and decoding, obtain each MAC PDU according to the code modulation mode of aforementioned acquisition;

Step 3033: after the decoding, carry out CRC check according to the CRC in the MAC PDU, thereby judge current MAC PDU to misuse in statistics.

According to above step, by to this burst, promptly the crc error rate of channel is added up correlated channels quality informations such as just can drawing BLER.

Step 304:SS is according to these decode results and channel quality measurement information, judges and oneself whether can use described other the code modulation mode of burst, is used to carry out the adjustment of link circuit self-adapting; Perhaps, SS feeds back to the base station with metrical information, is applied to the RRM of base station, comprises by the base station adjustment of link circuit self-adapting is carried out in the quality judgement of burst.

For example the described link circuit self-adapting adjustment process of step 304 is further described below, suppose to measure the BLER information of certain burst A in step 303, the link circuit self-adapting process comprises:

At first, terminal compares according to the measurement result of step 303 pair oneself and other channel, if judge under the current own residing wireless channel environment, employed code modulation mode is compared BLER during with the business datum that receives burst A and is wanted high, the present employed code modulation mode of more suitable use burst A then is described under the residing channel circumstance of present terminal.

Here only be that example illustrates, under the actual conditions, can come flexible utilization, to determine to carry out link circuit self-adapting how according to the multiple information that measures with BLER.For example, before making described judgement, terminal also can be measured the signal to noise ratio of corresponding burst, because may be because the transmitting power of burst A than the height of own current burst, and causes burst A transmission quality when own present position receives good.

Then, carry out the self adaptation adjustment of link.That is to say that terminal is according to the result who judges, make the conclusion of the modulation system that requires to alternate coding, robustness with maintenance link, after judging, send to the base station, indicate the new code modulation mode that oneself needs replacing in this message by the DBPC-REQ air-interface information.

Then, the base station receives after the DBPC-REQ air-interface information, uses described new code modulation mode to transmit the data of this follow-up SS, and returns the DBPC-RSP response message, finishes the link circuit self-adapting process.

By above-mentioned link circuit self-adapting process, metrical information (comprising BLER/BER/FER/SIR/CINR/RSSI etc.), decode results to each channel can be used as the accurate basis for estimation that system realizes link circuit self-adapting, come its shared Radio Resource is changed, the parameter of avoiding emulation to provide can not definitely reflect real wireless link condition.

Again the described RRM that is applied to of step 304 is illustrated below.RRM mainly is at the OFDMA multi-access mode at present, and this mode relates to the distribution of time frequency two-dimensional resources.Because wireless transmission can experience the decline of wireless channel, when terminal distribution on different time frequency two-dimensional resources, its decline situation is different, therefore the base station is when carrying out RRM and scheduling, preferably needs the channel feedback situation of terminal on different time frequency two-dimensional resources (as BER/BLER/FER/SIR/CINR etc.).

In the following example, suppose that in the above terminal has measured the relevant informations such as BLER/SIR of each channel in the step 303, the RRM process comprises:

At first, terminal compares according to the measurement result of step 303 pair oneself and other channel, if shared Radio Resource burst under the current own residing wireless channel environment, comparing BLER under using current code modulation mode during with the business datum that receives burst B wants height or SIR low, then illustrate under the residing channel circumstance of present terminal, shared physical resource and employed code modulation mode are not suitable especially, and more suitable comparatively speaking use burst B is shared physical channel resources or employed code modulation mode at present.

Terminal feeds back to the base station with these information by wireless air interface then.In the above in the process, but the terminal energy measurement on a lot of physical resources same feedback information give the base station, may also have a lot of terminals to feed back similar information simultaneously and give the base station.

Then, carry out RRM.Promptly, the base station is for the robustness of maintenance link and improve systematic function as much as possible, result at each terminal feedback, and according to wireless resource management algorithm, dynamically adjust and distribute shared Radio Resource of each terminal and employed code modulation mode, and and transmitting power coordinate, carry out unified planning, realize carrying out RRM and distribution and link circuit self-adapting process.

The strategy that carries out RRM according to the feedback result of terminal for the base station can comprise:

A) may be just transmitting power by improving terminal burst so that current link has more robustness, and do not remove to change code modulation mode, keep onesize air interface data rate, also do not go to change shared physical channel resources (the shared physical channel resources of the change of mentioning among the present invention is refered in particular to the time-frequency two-dimensional air interface resource under the OFDMA multi-access mode).

B) under the prerequisite of the robustness that can not destroy current link, also may pass through to reduce the transmitting power of terminal burst emission to save base station power consumption, the perhaps further reasonable distribution of guaranteed output, and do not remove to change code modulation mode, keep onesize air interface data rate, also do not go to change shared physical channel resources (the shared physical channel resources of the change of mentioning among the present invention is refered in particular to the time-frequency two-dimensional air interface resource under the OFDMA multi-access mode).

In a word, the base station in the process of RRM and scheduling and link circuit self-adapting, can the adjustment of the adjustment of code modulation mode, transmitting power, under the OFDMA multi-access mode shared time frequency two-dimensional resources adjustment this make a strategic decision flexibly aspect three.Can there be different strategies in different manufacturers.

According to above-mentioned steps, metrical information (comprising BLER/BER/FER/SIR/CINR/RSSI etc.), decode results can be as the foundations of RRM.Unified RRM and scheduling can more carried out in the macroreticular scope according to these information in the base station in the scope of base station or by back-end network.

Above embodiment is that example describes with IEEE 802.16 systems.Be understood that,, can use the present invention for the wireless access system of non-resource reservation mode.

The above only is preferred embodiment of the present invention, and is in order to restriction the present invention, within the spirit and principles in the present invention not all, any modification of being done, is equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims

1, a kind of implementation method of link circuit self-adapting is applied to the communication mode that non-resource is reserved, and terminal is measured the quality of channel information that oneself is communicated by letter and takies; It is characterized in that this method is further comprising the steps of:

A, terminal are measured other quality of channel information;

2, method according to claim 1 is characterized in that, the step that the described terminal of steps A is measured other quality of channel information comprises:

Terminal receives the system-frame that the base station sends, and reads the code modulation mode of each resource section burst in this frame of putting down in writing in this system-frame;

According to each burst code modulation mode that reads each burst in this system-frame is carried out demodulation coding;

Each data cell that obtains behind the demodulation coding is carried out the measurement of transmission error rate statistics and signal quality respectively, draw other corresponding each channel quality informations according to error rate statistics and measurement result.

3, method according to claim 2 is characterized in that, described step of carrying out the transmission error rate statistics comprises:

Value to the CRC CRC in the data unit is carried out CRC check;

Transmit the positive false information of this data cell according to the check (CRC) outcome record;

Repeat above step, obtain the positive false information of once above transmission data units, and error rate is added up.

4, method according to claim 2 is characterized in that, described error rate comprises: bit error rate BER, block error rate BLER, frame error rate FER.

5, method according to claim 2 is characterized in that, further comprises: in the system-frame that the base station sent, arrange the burst order from low to high successively according to the code modulation mode required signal-to-noise ratio;

Terminal judges when the transmission error rate that certain burst is measured is higher than certain set point when each burst carries out demodulation coding in to system-frame, ignores the statistics of the transmission error rate of the burst of this burst back of system-frame and the measurement of signal quality.

6, method according to claim 1 is characterized in that, the measurement of described signal quality comprises: signal interference ratio SIR, year dried making an uproar than CINR or received signal intensity RSSI.

7, method according to claim 1 is characterized in that, the described step of carrying out the adjustment of link circuit self-adapting of step B comprises:

The channel quality information that terminal takies oneself and other channel quality informations compare, whether judge under the terminal present located wireless link channel environment code modulation mode and the pairing Radio Resource of suitable other channels of use, if then ask the base station this terminal to be carried out the adjustment of link circuit self-adapting.

8, method according to claim 1 is characterized in that, step B further comprises:

The channel quality information that terminal takies oneself and other channel quality information feedback are given the base station;

The base station is adjusted the Radio Resource of distributing to each terminal according to whole all users' channel quality information and resource situation.

9, method according to claim 1 is characterized in that, described channel is time interval resource, the frequency resource under the FDMA or the two dimension of the time slot frequency under the OFDMA resource under the TDMA.