CN100393010C - Base station resolution prefixing method in wide-band code division multi-address system - Google Patents

Abstract

The present invention puts forward a method for accessing detection prefixes and conflict prefixes in the discrimination of base stations in a grouping transmission channel of a WCDMA system. A terminal selects a usable access resource to emit AP for requiring access according to access resource information broadcast by a common grouping channel state indication channel (CSICH); a base station judges the type of an access prefix according to the possible range of a CD prefix recorded in the previous time segment; if the received prefix falls in the possible range of the CD prefix, the prefix can be judged as CD; else the prefix is AP. The base station predicts an AP prefix confused with the CD prefix to be received, and determines the range of the AP prefix. The system broadcasts that the access resources corresponding to the prefixes AP are unavailable through the CSICH channel; the base station carries out other treatments. The method of the present invention makes AP and CD discriminated by the base station under the condition that AP and CD not only share scrambling codes but also share signatures, decreases the situation that the terminal is confused by the base station in the access process, and enhances the capacity of common grouping channels.

Description

The method of base station resolution prefixing in a kind of broadband CDMA system

Technical field

The present invention relates to Wideband Code Division Multiple Access (WCDMA) (WCDMA) system in the field of mobile communication, specifically, relate to the process of processing CPCH in base station in the WCDMA system.

Background technology

In CDMA cellular system, a plurality of users are that shared identical frequency band communicates.At transmitting terminal, narrowband data signal obtains Broad-band Modulated Signal and sends behind the specific scrambler of user (PN sign indicating number) spread-spectrum; And at receiving terminal, the receiver scrambler identical despreading of being correlated with to received signal with transmitting terminal, thus restore narrowband data signal.The effect of scrambler is to distinguish each different channel when multiplexing.

CPCH (CPCH) is a uplink transport channel in the WCDMA system, and the packet burst data that are used for terminal in the sub-district send.CPCH CPCH is mapped on the physical common grouped channels (PCPCH), by the message part loaded packet data of physical common grouped channels PCPCH.Be to rely on different scramblers to distinguish between the physical common grouped channels PCPCH, the base station is assigned 64 scramblers in each sub-district, shared by the terminal in the sub-district.

Clash in order to prevent different terminals from using same scrambler, realize the terminal shared resource, before the base station sent data, needing the first to file resource was scrambler in terminal, discharged behind the pending data end of transmission again.3G (Third Generation) Moblie is organized 3GPP to stipulate to adopt and is avoided conflict based on having DSMA-CD (the Digital Sense Multiple Access-Collision Detection) method of catching indication fast, reaches resource-sharing.This method consists two processes, the state indicating channel CSICH of the CPCH that at first to be terminal send according to the base station obtains the pre-process of physical common grouped channels PCPCH state, can learn through this process terminal whether specific PCPCH is occupied, thereby select idle PCPCH transmission; The state information of PCPCH can constantly be upgraded by CSICH broadcasting.Be formal procedures then, formal procedures is divided into access contention, collision detection and transfer of data three phases again, at first, terminal is utilized specific access to detect prefix AP and is required to insert corresponding PCPCH (s), and whether the base station is responded with corresponding Access Preamble AP AICH Acquisition Indication Channel AP-AICH and can be inserted; Then, confirm by specific access interference prefix CD and collision detection/Channel Assignment indicating channel CD/CA-ICH or assign the physical common grouped channels PCPCH channel resource that refers in particular to; At last, confirm physical common grouped channels PCPCH, transmit data.The existence in collision detection stage is for fear of a kind of like this conflict: when two terminals detect prefix AP and apply for same physical common grouped channels PCPCH with same access simultaneously, the base station also can be considered as affirmative acknowledgement (ACK) by another terminal to the affirmative acknowledgement (ACK) of one of them terminal, thereby causes conflict; For fear of conflict, next terminal can be sent access interference prefix CD in mode at random, and request confirms, because access interference prefix CD sends at random, therefore the CD that sends of two terminals can be not identical, and different like this terminals have just been separated by the base station.

Specifically, said method has two kinds of access waies, and the one, terminal selective channel pattern, the one, the flexible channels assignment mode, its access procedure is respectively as Fig. 1, and is shown in Figure 2.With Fig. 1 is example, terminal is sent to insert and is detected prefix AP, require specific PCPCH, the base station is sent corresponding Access Preamble and is caught to indicate to respond whether allow access, terminal is sent access interference prefix CD then, carries out specific PCPCH collision detection, and collision detection is finished by collision detection/Channel Assignment indicating channel in the base station, confirm PCPCH at last, carry out data and transmit.The difference of two kinds of access waies is that terminal selective channel pattern is to select physical common grouped channels PCPCH within the specific limits by terminal, and the flexible channels assignment mode then is to specify PCPCH by the base station according to the needs of terminal.

Inserting the expression formula that detects prefix AP is:

$C_{c\_\mathrm{accn},s}\left(k\right)=c_{\mathrm{long},1,n}\left(i\right)\×C_{\mathrm{sig},s}\left(k\right)\×e^{j(\frac{\mathrm{\π}}{4}+\frac{\mathrm{\π}}{2}k)},$ k＝0，1，2，3，...，4095

Wherein, C _{Sig, s}(k) be the 16bits signature signal of the prefix repetition of carrying, c _{Long, 1, n}(i) be the real part of up long scrambler.

And the expression formula of access interference prefix CD is:

$C_{c\_\mathrm{cdn},s}\left(k\right)=c_{\mathrm{long},1,n}\left(i\right)\×C_{\mathrm{sig},s}\left(k\right)\×e^{j(\frac{\mathrm{\π}}{4}+\frac{\mathrm{\π}}{2}k)},$ k＝0，1，2，3，...，4095

Wherein, C _{Sig, s}(k) be the 16bits signature signal of the prefix repetition of carrying, signature is selected within the specific limits at random by terminal, to reach the purpose by signature difference different terminals; c _{Long, 1, n}(i) be the real part of up long scrambler.

By last two formulas as seen, the access detection prefix AP and the access interference prefix CD of terminal emission are duplicate in form.The channel request that access detection prefix AP that base station needs basis is received and access interference prefix CD come processing terminal, but because access detects prefix AP and access interference prefix CD is just the same in form, therefore inserting under the situation that detects prefix AP and the shared scrambler of access interference prefix CD, both can't be differentiated in the base station, thereby can not to tell the application that terminal sends be any type in the base station, can't finish access procedure.

For the problems referred to above, existing solution is different access signature to be distributed to respectively to insert detect prefix AP and access interference prefix CD, and the signature that obtains by parsing number is inferred the type of prefix.But do like this and just reduced terminal and can select the number of signing at random, make it be approximately half of original signature number, and different terminals is by selecting to obtain different separately signatures at random in access procedure, and the base station is again by different signature distinguishing terminals; The signature that can be used for selecting at random is few, and different terminals chooses the chance of same signature just to increase, thereby also can cause the base station can not correctly recognize the terminal of initiating application, especially easier this kind situation that occurs when application is more.

Summary of the invention

For the access that solves under the shared scrambler situation of the correct identification in base station detects prefix AP and access interference prefix CD, the present invention proposes among a kind of WCDMA packet transmission channel CPCH of system, base station resolution inserts the method that detects prefix AP and access interference prefix CD.

The method of resolution prefixing of the present invention may further comprise the steps:

1) terminal is chosen available access-in resource and is sent access detection prefix AP according to the access-in resource information of CPCH state indicating channel CSICH broadcasting, requires to insert;

2) type of Access Preamble is differentiated according to the possible scope of the CD prefix of previous time period record in the base station, searches the prefix corresponding PCPCH that signs according to PCPCH and the correspondence table of CD, is applied as the PCPCH of correspondence, and then prefix is CD, otherwise prefix is AP;

3) the base station prediction detects prefix AP with the access that the access interference prefix CD that will receive obscures mutually, determines its scope, and system is unavailable by the CSICH channel radio access-in resource corresponding with above-mentioned prefix AP;

4) other processing is carried out in the base station.

Adopt the method for the invention, compared with prior art, make and insert to detect prefix AP and access interference prefix CD in that not only share scrambler but also share can be by base station resolution under the situation of signature, reduce the situation that obscure terminal the base station in access procedure, thereby improved the capacity of CPCH CPCH.

Description of drawings

Fig. 1 is the access procedure schematic diagram of terminal selective channel pattern.

Fig. 2 is the access procedure schematic diagram of flexible channels assignment mode.

Fig. 3 is the flow chart of the method for the invention.

Embodiment

Be described in further detail below in conjunction with the enforcement of accompanying drawing technical scheme.

Fig. 1, Fig. 2 illustrate in background technology, repeat no more herein.

Fig. 3 is the basic procedure of the method for the invention.Each terminal can be learnt the busy-idle condition information of the PCPCH channel of desire application by the CSICH channel before sending application, whether decision sends AP.Each PCPCH channel is by three state: do not apply for, apply for, take, for the PCPCH channel of applying for, having taken, it is labeled as busy, can infer and the prefix CD that may receive according to being labeled as busy PCPCH channel, and the pairing PCPCH channel of AP that can obscure with it is labeled as busy at next time slot, may just can not be issued with the AP that CD obscures mutually like this.If the prefix that receive the base station drops in the possible range of CD prefix, just be judged as prefix CD, remaining is exactly prefix AP.Information is sent according to different prefixes in the base station, carries out collision detection, confirms required PCPCH channel at last, finishes data and transmits.Simultaneously, if original access application is in the collision detection stage, then need to send CD and do collision detection, its corresponding PCPCH channel also need show occupied, can PCPCH is consistent as far as possible with the correspondence table of AP and CD by this point, additional markers can be seldom for busy PCPCH number because differentiating AP and CD like this.

Concrete implementation procedure is as follows: initialization PCPCH and AP, and the correspondence table of CD makes the AP of same PCPCH correspondence identical as far as possible with CD; The busy-idle condition table of initialization PCPCH, each PCPCH channel has three state, and application is not applied for, takies.The state of PCPCH channel is broadcasted in the sub-district by CSICH, and the PCPCH channel tag of applying for, having taken is for busy.Terminal sends to insert according to the state of PCPCH channel and detects prefix AP, and request inserts, and the base station receives the prefix signature, searches the prefix corresponding PCPCH that signs by PCPCH and the correspondence table of CD, is applied as the PCPCH of correspondence, and prefix is CD, and other prefixes are AP.If AP, then for acceptable application, the PCPCH channel of correspondence is changed to applies for, find simultaneously also to be designated as and apply for the pairing PCPCH channel of the AP that the CD that will receive obscures, remove out-of-date application simultaneously, the PCPCH resource mark is not application.The CPCH channel carries out other processing then.New state for the PCPCH channel is broadcasted again.

Claims (2)

1. the method for base station resolution prefixing in the broadband CDMA system is characterized in that, may further comprise the steps:

1) terminal is chosen available access-in resource and is sent access detection prefix (AP) according to the access-in resource information of CPCH state indicating channel (CSICH) broadcasting, requires to insert;

2) type of Access Preamble is differentiated in the base station according to the possible scope of the access interference prefix (CD) of previous time period record, search the corresponding PCPCH of prefix signature according to physical common grouped channels (PCPCH) and the correspondence table of CD, PCPCH as correspondence is applied, then prefix is CD, otherwise prefix is AP;

3) the base station prediction detects prefix (AP) with the access that the access interference prefix (CD) that will receive is obscured mutually, determines its scope, and system is unavailable by the CSICH channel radio access-in resource corresponding with these prefixes AP;

4) other processing is carried out in the base station.

2. the method for claim 1, it is characterized in that: described access-in resource information is the busy-idle condition of physical common grouped channels (PCPCH).

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