NO331702B1 - Method and apparatus for blind code detection - Google Patents

Abstract

The present invention relates to a receiver comprising a blind code detection device (15) for determining the identity of multiple channels over which information is to be transmitted when the identity of all channels is not known by the receiver. This blind code detection device (15) then generates a candidate channel list followed by the identity of selected channels among the several available channels. A multi-user detection device (16), adapted to respond to the blind code detection device (15), then processes these channels on the candidate code list.

Description

Background

The present invention mainly relates to communication systems with code division multiple access (CDMA). More specifically, the present invention relates to a CDMA receiver.

CDMA systems use spread-spectrum techniques and multi-code operation to produce higher network capacity within a given bandwidth than a single-code system. The increased capacity can be aimed at a single user or be distributed among several users.

To implement a receiver, a CDMA system mainly requires knowledge of the identity of the codes used to produce the transmitted signal. The receiver in user equipment (UE) must know the identity of all codes, a subset of codes or none of the codes that can be used for a given transmission. The codes in connection with signals directed to the desired UE will hereafter be referred to as "own UE codes", while codes in connection with signals directed to other receivers will hereafter be referred to as "other UE codes". Such equipment typically includes means in the receiver to get to know or learn the characteristics of own UE codes via initial programming, signalling, recording methods or various other techniques which may then include trial and error, which may then be inefficient from an effect point of view - or behavioral standpoint. Equipment may or may not be equipped with means to learn the characteristics of other UE codes. Specific codes used to transmit data may be immutable or may change over time.

Demodulation of data associated with any code will be subject to degrading bit error rate (BER) caused by interference between own UE codes and/or other UE codes. The receiver can benefit from knowledge of the characteristics of proprietary or other UE codes by adopting improved methods that enable a lower BER at a given signal-to-noise ratio in a radio channel with certain multipath characteristics.

Multi-user detection (MUD) is an example of a receiver method that simultaneously processes received signals associated with several different codes in an attempt to minimize the effect of mutual influences and produce a lower BER, or possibly the same BER under less favorable signal/ noise ratio (SNR) or multipath conditions. MUD works optimally when configured for the actual set of transmitted codes. To achieve this, MUD requires knowledge of the identity of transmitted own UE codes and transmitted other UE codes. In addition, MUD generally requires an assessment of the transmission channels through which the signal is sent. This estimation of the transmission channel is then called the "channel response" or the "channel estimate". The transmission channel can be the same for all codes. If transmission diversity exists, antenna beam steering or other methods of signaling diversity are used at the transmitter, and different transmission channels can then be associated with different codes.

One way to implement MUD is to configure the receiver for all codes that may or may not have been transmitted. However, there are two disadvantages which make this method undesirable, and possibly impractical. For the first relationship, the more codes a MUD device is configured to process, the greater the number of calculations that will be required to demodulate the transmitted data. Configuring a receiver only for codes that have been transferred will therefore require less power and a shorter processing time. Second, the BER value will often be degraded if the MUD is configured to process a relatively large number of codes. Configuring a receiver only for the codes that have been transmitted will thus usually result in an improvement of

PRAY.

In time-slotted CDMA systems utilizing MUD, for example in 3GPP TDD systems, one or more channel separation codes in one or more time slots are allocated to coded composite transport channels (CCTrCH units). In each time slot, several CCTrCH units can be transmitted, and can then be directed into one or more UE units.

Each transmitted code is associated with a mid-part code exchange that may or may not be shared with other transmitted codes. The UE judges the channel response based on processing from the received mid-parts. The relationship between the mid-part code switching and transmitted codes is not exclusive, as detection of a particular mid-part code switching in no way guarantees that an associated code has been transmitted. However, in the specific case where one has Kcell=16 in TDD, the relationship will be special.

As an example, and under all setups, a CCTrCH will be provided with an allocation of channelization codes and time slots, and these are then signaled to the UE. The UE will therefore have a list of assigned codes. However, since not all assigned codes are used in every transmission, the UE will have partial information (that is, information that applies to its own UE codes). The list of other UE codes is then not available, except in certain, special cases where some indication of the total number of codes will be indicated through physical layer signaling.

Each transmitted code is a combination of a channelization code, a channelization code specific multiplier and a reversal code. The reversal code is signaled to the UE,

and code specific multipliers set in conjunction with the channelization codes, so that the identity of the channelization code itself is the only one of the three that needs to be determined.

If a code allocated to a CCTrCH unit is not transmitted, then the CCTrCH will be in discontinuous transmission (DTX). A CCTrCH is said to be in "partial DTX" if not all of the allocated codes are transmitted within a given time slot. It is said to be in "full DTX" if none of the assigned codes are transmitted within a certain transmission pool.

The determination of the transmitted codes within an entire transmission pool can then be derived from the transport format combination index (TFCI) which is then signaled to the UE and multiplexed with the data signal. TFCI is transmitted in the first time slot allocated to a CCTrCH unit, and possibly in subsequent time slots in the same pool. Each UE may be in possession of the received TFCI to determine the transmitted own UE codes in each time slot of the transmission pool. However, this requires demodulating received data symbols and performing various other processes to decode and interpret TFCI information. In certain receiver designs, an inherent latency of these processes could lead to the identity of transmitted, own codes not being available when received data in the first time slot (and possibly certain subsequent time slots) in the transmission pool is not processed in the MUD device.

Consequently, there is a need for an improved receiver which will have the ability to more effectively identify the incoming transmission channels.

Summary

The present invention provides a user equipment (UE) for receiving communication channels in time frames that include several ten-slots, where the time slots have data signals for several channels, characterized by the features specified in the attached patent claim 1.

Further features of embodiments of the invention's UE are specified in the accompanying non-independent patent claims 2-14.

The present invention provides a method for receiving communications in time frames comprising several time slots, where these time slots comprise data signals for several channels, characterized by the features specified in the attached patent claim 15.

Further features of embodiments of the method of the invention are indicated in the accompanying non-independent patent claims 16-28.

A receiver can be arranged to receive communication channels within time pools which are divided into several time slots, where then these time slots comprise data signals for several different channels. The receiver then includes: 1) a data estimation device for decoding data signals in the time slot, and which then includes a blind code detection device to determine the identity of the several channels present when the identity of all channels is not known by the receiver and to generate a candidate channel list filled with the identity of selected channels among the plurality of available channels, and 2) a MUD device is arranged to respond to the dummy code detection device, by processing these channels on the candidate channel list.

Brief description of the drawings

Figure 1 is a block diagram of a receiver in accordance with the preferred embodiment of the present invention. Figure 2 is a block diagram of a blind code detector device in accordance with the preferred embodiment of the present invention. Figure 3 shows a procedure for generating the candidate code list in terms of the standard middle portion in accordance with the preferred embodiment of the invention. Figure 4 indicates a procedure for generating the candidate code in the usual middle lot case in accordance with the preferred embodiment of the invention. Figure 5 indicates a procedure for generating the candidate code list in the specific UE case in accordance with the preferred embodiment of the invention. Figure 6 indicates a procedure for a search allocation function (searchAlloc) in accordance with the preferred embodiment of the invention. Figure 7 indicates a procedure for using the TFCI function in accordance with the preferred embodiment of the invention. Figure 8 is a diagram showing the construction of the system matrix A; in connection with the preferred embodiment of the present invention. Figure 9 indicates a procedure for the detection function in terms of its own UE code and carried out in accordance with the preferred embodiment of the present invention. Figures 10A and 10B together show a procedure for the detection function in connection with other UE codes and carried out in accordance with the preferred embodiment of the present invention. Figure 10 shows the way in which figures 10A and 10B are arranged in relation to each other.

Detailed description of the preferred designs

Reference should now be made to Figure 1, where it is shown that a receiver 19, preferably in a user equipment (UE), (mobile or fixed), comprises an antenna 5, an isolator or switch 6, a demodulator 8, a channel determining device 7 and a data estimation device 2. After the data estimation device 2, the signals are passed on to a demultiplexer/decoder 4 to be processed there in accordance with well-known methods. The data estimation device 2, which is connected to the demodulator 8 and the channel estimation device 7, comprises a blind code detector (BCD) unit 15, a multiuser detection device (MUD) 16 and a TFCI decoder 17. The MUD device 16 decodes the received data using the channel impulse responses from the channel estimation device, and a set of channelization codes, spreading codes and channel response offsets from the BCD unit 15. The MUD device 16 may use any running MUD method to estimate the data symbols in the received communication, such as a linear equalization circuit (MMSE-BLE), for the least square error, a zero-forcing linear equalizer block (ZF-BLE) or several coordinated detectors, namely each to detect one of the several acceptable CCTrCH units associated with the relevant UE. Although the BCD unit 15 is shown as a separate device, this BCD unit 15 can be included as part of the MUD device 16. If desired, the code energy measuring part of the BCD can form part of the MUD, that is, a front end component of the MUD -device (the matched filter) has the same component that performs the BCD code energy measurement function, which then measures the code energy in a set of codes, with the BCD output fed back to the MUD so that the rest of the MUD functions only work on a subset of those codes which is originally measured by the front end.

The BCD device 15 is connected to the demodulator 8, the channel estimation device 7, the TFCI decoder and the MUD 16. The channel determination output of the device 7 forms an input to the code energy measurement function of the BCD device 15. The BCD device outputs the set of channelization codes, spreading factors and channel response offsets to the MUD devices. 10 (or single user detection, that is SUD) for use in the current time slot. The BCD unit 15 is performed for each time slot in a frame where the UE has a downward assignment.

The dummy code detection function outputs to the MUD or SUD the set of channelization codes, spreading factors, and channel response offsets to be used in the current time slot. It is also indicated against the TPC function in channelization codes to be used for the SIR measurement.

In the MUD configuration, BCD15 code energies are measured and decisions are made regarding which own UE codes and other UE codes are to be included or not included in the detected code list on the output side. The detected code list is defined here as the list of codes that remains when all the codes in the candidate list have been examined, and those that are unable to satisfy all of the criteria mentioned above are then removed from the candidate code list. Basically, BCD populates the candidate code list based on the head allocation and midpart allocation method, and then excludes some of these codes from the list based on the energy measurement or TFCI, which then forms the output of the MUD. In the CELL DCH state, P-CCPCH and up to four DCH CCTrCH units assigned to the own UE can be present, and then together with codes for other UE units. In CELL_FACH states, P-CCPCH and a common channel CCTrCH intended for own UE can be present, and then together with codes for other UE units. A common channel code is treated in the same way as a DCH code for its own UE, except that a common channel code transmitted as a control unit is considered detected if its associated midportion has been detected using the midportion detection function, regardless of its code energy. The P-CCPCH is treated as its own unique CCTrCH unit: that is, it has no TFCI and thus will not be subject to large TFCI samples in the code detection function, since it is always transmitted as a control unit, its detection decision will only be based on one's midrange detection, otherwise it will be treated like any other aqueous channel. The characteristics of transmitted and non-transmitted codes that are signaled by a TFCI device and are made available by the fast TFCI function one or two time slots after receipt of the TFCI has been utilized, when available.

In the detection configuration for single connections (SUD) all allocated own UE codes are included, while any other UE codes are excluded from the detected code list on the output side. Because the MUD configuration is selected for time slots containing common channels, the SUD configuration will not contain any special logic for P-CCPCH. BCD uses the following sub-functions as indicated in Figure 2.

Reference should now be made to figure 2, where it is shown that the unit 15 for blind code detection (BCD) comprises a candidate code list generator 30, code energy measurement units 32 and a code detection unit 34. The inputs and outputs of these units are also shown in figure 2.

Generation (30) of candidate code list

Depending on the allocation scheme for the time slot midpart, the leading unit indicator and optionally the detected midpart offset and received TFCI, the candidate channelization codes for both own UE and other UEs are selected (only for the MUD configuration).

Code energy measurement (32)

For the MUD configuration, the energy for each of the candidate codes is measured based on the program symbol for the candidate codes on the output side of a custom filter.

Code detect (34)

Codedetect performs the following:

• Own UE code detect (only for MUD configuration)

Candidate codes for each CCTrCH are retained in or removed from the candidate list depending on their code energy, namely full DTX status, status of the received TFCI and the relative time slot within the transmission pool.

• Second UE code detect (only for MUD configuration)

As soon as own UE codes have been detected, other UE codes are detected depending on their code energy with a threshold based on the energies of own UE codes and on whether or not it is known that at least one UE code has certainly been

transfered.

• To remove certain weak codes if too many codes remain as accepted after the threshold tests indicated above.

• Format output for large MUD or SUD.

ENTRANCES

Data

Data received by code energy measurement (CEM) 32:

OddRxData, odd received data (after mid-part deletion).

Same size RxData, same received data (after mid-part deletion) at 32 OddChResp Q<k>), * = % 2,~, K f odd channel response.

LikeChResp * > * = 1»2,—» K f equal channel response.

The list of mid-part transitions detected by the channel estimation function 7 is provided to the generator (CCLG) 30 for the candidate code list and includes:

<*>etMidList (16), the switching number (the k-value of detected middle parts, 0 = no valid input.<*>detMidOffset (16), channel response switching for detected middle values.<*>nDetMid, the number of valid terms in detMidList and detMidOffset.

The transmission full discontinuous indicator (DTX) is set if the CCTrCH is in full DTX and is transferred to code detect (CD) 34.

TfcCodeList (4,224), namely the list of transmitted codes in the pool, as indicated by the received TFCI, per CCTrCH, 16 codes x 14 time slots, is provided to CCLG 32.

tfcCodeListValid (4), is set if the received TFCI has been decoded by the fast TFCI process and tfcCodeList contains valid data, per CCTrCH and is then transmitted to CCLG 30.

REGULATION

KCELL, the maximum number of mid-party exchanges this time slot is allocated to

CCLG 30 and CEM 32.

burstType, namely the burst type, this timeslot is transmitted to CCLG 30. beaconTSI, namely the lead timeslot indicator is transmitted to CEM 32.

allocMode, namely mid-partition allocation mode (standard, common or UE-specific), this timeslot is issued to CCLG 30.

MUD_SUD indicator, indicates MUD or SUD active in this time slot and is transmitted to CCLG 30, CEM 32 and CD 34.

This list of parameters for PhCH units allocated to own UE is then of the form:

<*>allocCode (phy chan), the channelization codes for allocated PhCH units are transferred to CCLG 30.<*>allocTimeslot (phy chan), namely the timeslots for allocated PhCH units are issued to CCLG 30.<*>allocSprFacot (phy chan), namely spread factors for allocated PhCH units are output to CCLG 30.<*>allocMidShift (phy chan), namely the mid-part shifts for allocated PhCH units are output to CCLG 30.<*>allocCCTrCH(phy chan), namely the CCTrCH number of allocated PhCH units {1-4=own UE or a common channel CCTrCH, 5 = P-CCPCH} are transmitted to CCLG30.

OUTPUTS

Data

The detected code list is issued by CD 34 and is of the form:

chanCode (16), namely the channel codes for detected codes, 0 = none

valid entry.

sprFactor (16), namely the spreading factors for detected codes.

midOffset (16), namely the channel response offsets for detected codes. chanCCTrCH (16), the CCTrCH number of detected code [0 = other UE code,

1-4 = own UE or shared channel CCTrCH5 = P-CCPCH}

chanTFCIflag (16), is set if code carries the TFCI unit in its CCTrCH. numCodes, namely the number of valid terms in chanCode, sprFactor and midOffset.

REGULATION

timeslotAbort, is set if no UE codes or P-CCPCH are available to

is demodulated, and thus further processing of the time slot is required.

BLIND CODE DETECTION PROCEDURE PROCESSING EACH DL TIME SLOT

Parameters

ownUEthresholdFactor, set to 0.1 and issued to CD 34. otherUEthresholdFactor, set to 0.7 and issued to Cd 34.

maxMudCodes, namely the largest number of channelization codes that MUD can

support, default setting 14, output to CD 34.

numSymbols, the number of symbols to estimate code energy, defaults to

30, can be as large as 61 (entire first data field), transmitted to CEM 32.

Midamble/Code association, the standard mid-party case (see Table 1), is submitted to

CCLG 30.

Control code(s) (always code number = 1 (and 2, if SCTD is applied), SF = 16). Beacon shift (always k = 1). Middle section k = 1 is used for the first antenna and k = 2

is used for the diversity antenna if SCTD is used for the guide channel.

Codes for the orthogonal variable spread factor (OVSF), SR = 16 only (see table

1) submitted to CEM 32.

Lr, within channel response lengths (see table 1) is output to CEM 32.

IMPLEMENTATION REQUIREMENTS

As an example, the fixed point requirements for the dummy code detection block are shown in Figure 1 (however, the number of bits used can be changed if desired).

Functional description

The candidate code list is the list of channelization codes and assigned parameters that may have been received in the time slot in question, and which are later subjected to threshold tests for the code detection function (CD) 34. This list is determined based on the time slot's midpart allocation scheme, the detected midpart exchanges, as well as information about the known number of transmitted codes derived from the received TFCI, if available from the fast TFCI process. In lead time slots, the codes for detected lead middle parts are marked to prevent rejection of the code detect function (CD) 34.

Control mark sent out with SCTD requires special treatment when creating the candidate code list (ccl). If only one of the two beacon center portions has been detected, then only one of them has been transmitted, or both have been transmitted but only one received. In this case, only the one detected beacon is entered in the candidate list as code 1 or code 2, depending on whether k = 1 or k = 2 has been detected. If both beacon midparts have been detected, and if the SCTD is not known to be turned off, then the two beacon codes will essentially be collapsed onto each other in the A-matrix, and then treated as a single code. In this case, only one code, namely code 1 & k = 1, is entered into the candidate code list. The guide sign k = 2 is then not transferred in itself.

STANDARD CENTRAL PARTIAL ALLOCATION FORM

In the standard midpart allocation scheme, each detected midpart will clearly indicate a set of channel separation codes that could have been transmitted, and should be included in the candidate code list. In beacon timeslots, the first and second beacon codes are included in the candidate code list if their respective middle portions have been detected. The beacon codes are flagged as not rejected by the code detect function 34. Once the candidate codes and their associated mid-party exchanges have been entered into the candidate code list, the list of parameters for PhCH units allocated to their own UE is searched to identify own UE candidate codes and their parameters. For own UE codes, and in the event that the transmitted codes are known from the fast TFCI, the candidate code list will be adjusted accordingly.

The procedure is as follows, and shown in the flowchart in Figure 3.

The process steps are:

Prepare the candidate code list (Sl).

Begin at (S2), setting ccl row = 1, index = 0.

In the presence of beacon time slots (S3),

<*>at S4, if midpart detection has been reported in the first beacon midpart, then S4A at S5 will enter the first

beacon lot, and into the candidate code list together with channelization code, channel response switching and spreading factor, and

then sets the cclAccept flag for the beacon code, so that this

cannot be rejected by the code detection function.

<*>if the center part detection has not reported the first guide mark center part S4A, but has reported the second guide mark center part S6A, with S7, the same is done for it

second

middle part.

• Find the codes for each detected midportion in Table 1 (remaining if this is a beacon time slot) at S8. S8 runs through a loop to examine all midsections. • IS10 and S11, the codes found in the candidate code list at S12 are copied, together with their associated center part shifts, channel response shifts and spreading factors. S10 loops through until all n-codes have been examined. Strain through loops for all rows (16). • After all codes have been entered in the candidate code list, a separate UE allocation list is searched for each candidate code. The searching Alloc routine (S12) is shown in detail in Figure 6. For candidate codes found in the own UE allocation list, their CCTrCH numbers are added to the candidate code list. Candidate codes that are not found on the own UE allocation list will retain the clarified CCTrCH number equal to zero, which will then indicate that the code has not been allocated to the own UE. • For own UE codes, and for each cclAccept flag, if the transmitted codes in this time slot are known from the fast TFCI, then Sl3:<*> for transmitted codes is the setting of the cclAccept flag so that these codes cannot be rejected of the code detect function.<*>for non-transmitted codes, these are corrected from the candidate code list.

Use of the TFCI routine is shown in more detail in Figure 7.

COMMON CENTRAL ALLOCATION FORM

In the common mid-party allocation scheme, in non-leader time slots, only one (namely the "common") mid-party exchange is transmitted. This indicates a set containing the number of channelization codes transmitted in the timeslot. In beacon timeslots, one or two midpart exchanges plus the common midpart exchange are indicated, indicating the number of channelization codes that have been transmitted in the time slot. Downmark codes and their mid-part interchanges are included in the candidate code list if their respective mid-part interchanges have been detected, and whose codes are flagged as not rejected by the code detection. The number of channelization codes specified by the common mid-party switch is not used. If the common mid-party switch is not detected, there are no codes other than possibly leading code codes for entry on the candidate code list. In beacon timeslots, the candidate code list is filled with all 14 remaining SF = 16 channelization codes, each of which is assigned to the detected common mid-party exchange. In time slots that do not apply to beacon, there can be either one code SF = 1 or up to 16 codes, SF = 16, in the time slot, and SF will weaken the value of a code in this time slot in the own UE allocation list is then tested and used to determine whether the candidate code list is to be filled by one code SF = 1 or 16 codes, SF = 16, each time in connection with the detected mid-party exchange.

As soon as the candidate codes and your assigned mid-party exchanges have been entered into the candidate code list (ccl), the list of parameters for PhCH units allocated to own UE is searched to identify own UE candidate codes and their parameters. P-CCPCH cannot be in a common mid-party time slot. For own UE codes, and in the case that the transmitted codes are known from the fast TFCI, the candidate code list is adjusted accordingly.

The procedure is then as follows, and as indicated in the following flowcharts:

Reference is made to figure 4;

In Sl, the candidate code list is prepared and started in S2.

In the reference time slot, S3A, the situation is as follows:

<*>if the mid-party detection has reported the first guide mark middle part then S4A is led the first guide mark middle part

into the candidate code list along with its channelization code, channel response shift and spreading factor, and the cclAccept flag is set for beacon code so that it cannot be rejected by code detection function in S5.

<*>if the midpart detection has not reported the first guide mark midpart at S4B, but has reported the second

guide mark middle part at S6A, then the same is done for the other

middle part, S7.

<*>stopped if the common mid-part shift (2 < k <=Kcell) has not been detected in S8A.<*>into the candidate code list all remaining channelization codes are entered, together with the common mid-part offset and SF = 16.

• A non-lead time slot, at S3B:

<*>stops the process if a common mid-part switch, as specified below, has not been detected in S9A.

<*>all but Kcell = 4: 0 < k <=Kcell.

<*>Kcell = 4:k=1,3,5or7.

• From the own UE allocation list, it is determined in a Sl 1 whether this is a time slot corresponding to SF = 16 or SF = 1. • When entering the candidate code list, all spreading factors (SF) are introduced, where SF = 16, iS12 and S13, or a SF = 1, at Sl 6, the channelization codes together with the common mid-part exchange and SF. • After all codes have been entered in the candidate code list, each candidate code is searched for in its own UE allocation list at Sl4. For candidate codes found in the own UE allocation list, their own CCTrCH numbers are added to the candidate code list. Candidate codes that are not found in the own UE allocation list will retain the prepared CCTrCH number equal to zero, which will then indicate that the code is not allocated to the own UE. • For own UE codes, and for each CCTrCH, in the case that the transmitted codes in this time slot are not known from the fast TFCI, the situation is as follows in Sl5:<*>that for transmitted codes the cclAccept flag is set so that they cannot be rejected by the code detect function.<*>for non-transmitted codes, these are removed from the candidate code list.

SPECIFIC MIDDLE PART ALLOCATION FORM FOR UE

In all mid-party allocation schemes, the UE has prior knowledge of mid-party exchanges that are allocated to its own UE codes. In standard and common mid-party allocation schemes, the UE will know mid-party-to-code relationships for codes that are possibly allocated to other UE units. However, in the specific mid-party allocation scheme for the UE, the UE has no knowledge of mid-party-to-code relationships for codes that are possibly allocated to other UE units. Because the UE has no knowledge of other UE mid-party exchanges, and channelization code relationships, it will be impractical to detect other UE channelization codes. For each detected mid-party exchange, the UE will simply examine its allocation list and add to the candidate code list the codes that are related to this, and no channelization codes for other UEs will then be added to the candidate code list. In beacon time slots and in the event that first or second beacon midparts have been detected, their respective codes will be flagged so as not to be rejected by the code detection function. The P-CCPCH cannot then be in a specific time slot for the UE. For all CCTrCH units, the situation is then such that if the transmitted codes are known from the fast TFCI, the candidate code list will be adjusted accordingly.

The procedure is then as follows, and as indicated in the flowchart in Figure 5:

In Sl prepare the candidate code list and start in S2.

In the beacon time slots and at S3A, the situation is such that,

<*>if the center part detection has reported the first guide mark center part, then S4A will lead the first guide mark center part

into the candidate code list along with its channelization code, channel response shift and spreading factor, and the cclAccept flag is set for the beacon code so that it cannot be rejected by the coded detect function in S5,

<*>if the midpart detection has not reported the first guide mark midpart over S4B, but has reported the second

guide mark middle part at S6A, then the same is done for the other

middle part, S7.

• For each detected mid-part exchange, a separate UE allocation list is searched for channelization codes that are related to this mid-party exchange in this

time slot.

• The heads that are found are copied into the candidate code list along with their associated midrange shifts, channel response offsets, spreading factors and CCTrCH units. For own UE codes (the only codes on the candidate list in this case), and for each CCTrCH, it is the case that if the transmitted codes in this time slot are known from the fast TFCI, then S14:<*>for transmitted codes, the cctAccept flag will be set so that these cannot be rejected by the code detect function.<*> for non-transferable codes, these are rejected from the candidate code list.

SEARCH IN ALLOCATED CODE LIST

The Searc/^//øc function, which is shown in Figure 6, is used for allocation schemes for common and standard middle lots. After all the candidate codes have been entered in the candidate code list. The own UE allocation list is examined, and any candidate codes found on the allocation lists are then, by definition, allocated to the own UE. The CCTrCH numbers for the candidate codes that are found are then copied onto the candidate code list. Candidate codes that are not found on the own UE allocation list will keep the clarified CCTrCH number equal to zero, which will then indicate that this code is not allocated to the own UE.

For the single user detection (SUD) configuration (Sil), codes belonging to other UEs are relieved from the candidate code list (Sl4).

USING TFCI FUNCTIONS

This function, useTFCI shown in Figure 7, prevents rejection from the decision for codes known to have been transmitted, and removes from the candidate code list codes known not to have been transmitted (S12, S13). This function is used for those CCTrCH devices where the TFCI has been decoded with the fast TVCI process, and

information about the transferred codes is thus available.

ENTRANCES

Data

A list of midpart transitions detected by the channel estimation function then has the form: • detMidList (16), the transition number (k-value) of detected midparts, 0 = no valid input, however any number can be used (99 for example) to enter invalid input. <*>detMidOffset (16), channel response offset for detected midparts. <*>nDetMid, the number of valid members in detMidList and detMidOffset. • tfcCodeList (4.224), the list of transmitted codes within the transmission pool as indicated by the received TFCI, per CCTrCH, 16 codes x 14 time slots. • TfcCodeListValid (4), set if the received TFCI has been decoded by the fast TVCI process and the tfcCodeList contains valid data, for each CCTrCH.

REGULATION

KCELL, the maximum number of mid-part exchanges for this timeslot. burstType, burst type for this timeslot.

beaconTSI, beacon time slot indicator.

allocMode, mid-partition allocation mode (default, common or UE-specific) for

this time slot.

MUD_SUD indicator, indicates the MUD or SUD that is active in this time slot. List of parameters for PhCH units allocated to own UE, and then of the form:<*>allocCode(phy chan), channelization codes for allocated PhCH units.<*>allocTimeslot(phy chan), the timeslots for allocated PhCH units .<*>allocSprFactor(phy chan), spreading factors for allocated PhCH units.<*>allocMidShift(phy chan), mid-lot shifts for allocated PhCH units.<*>allocCCTrCH(phy chan), the CCTrCH numbers for allocated PhCHs {l -4=own UE or common channel CCTrCH, 5 = P-CCPCH}.

OUTPUTS

Data

Candidate code list of the form:

cclCode (16), the OVSF channelization code numbers for the candidate codes. cclMid (16), mid-party switches for candidate codes.

cclOffset (16), the channel response offsets for the candidate codes. cclSprFactor(l 6), the spreading factors for the candidate codes.

cclAccept(16), the acceptance flags for the candidate codes.

chanCCTrCH (16), CCTrCH number for detected code {0 = other UE code,

1-4 = own UE or common channel CCTrCH, 5 = P-CCPCH}.

CclTFCIflag(16), is inserted if code is forwarded TFCI in CCTrCH.

REGULATION

No

Operating sequence

This function works in every DL time slot.

Parameters

Midpart/code coordination, standard midpart case (see Table 2).

B = guide mark time slot, NB = time slot without guide mark.

For example, the detected middle part k=5 and Kcell = 8, burst type = 1, then the candidate codes are 9 and 10.

CODE ENERGY MEASUREMENT

Functional description

This function is only performed in MUD configuration. The code energy measurement function measures the energy in the candidate channelization codes by adapting the filtering of the received data to the system matrix to thereby form soft symbols and then measuring the energy in these soft symbols from each of the candidate codes. To reduce process processing, until only a limited number of symbols are determined. The customized filter is then:

The procedure is then as follows:

• For each of the cclNumcodes' candidate codes, two vectors are determined, bi, namely as'fc * , where n is the order of a candidate code within the candidate code lists, ,c(a*0,*W) is the spreading code sequence (the OVSF code sequence multiplied by a reversal code sequence ) for the nth candidate code, from table 4, is the channel response for a mid-part shift k that is related to the nth code on the candidate code list, where i = 1.2 represents the channel response for the odd or even channel, respectively. The channel response length output from the channel estimation is 114, but only the first 64 are used. The length of is always 16, and the length of ' is a function of Kcell, the maximum number of party exchanges, for this time slot, given as Lri table 3. • Two matrices (odd and even) or blocks of column vectors are formed of the vectors #"} »<n=*>..., cclNumCodes as shown in Figure 8. • For each of the two system matrices, each of the blocks described above can be repeated numSymbols times in decreasing order, as shown in Figure 8, to form A ;, when i = {odd, even}. • In time slot guide, if mid-partition alternations k = 1 and k = 2 were detected (SCTD is on and detected), add together the first two columns of each A;, eliminated the second column and reduced cclNumCodes by one. • Calculate the Hermitian values for the two system matrices Ai, where i={odd, even}, so that Ai<H> is formed, where i={odd, even}. • Determine nt>where i={odd, even}, for which the first 16<*>numSymbols flakes the data field Dl in even and odd received data sequences.

~*AN aH~

• Determine numSymbols for all candidate codes as s ~ •*r«* + j4««»r««™) where

* is of the form ...

• Calculate the energy for each of the cclNumCodes candidate channelization codes, which without a leader is: where !*f is the channel response for the mid-party exchange k=cclMidList(n) which is related to the nth code on the candidate code list and i=l,2 represents respectively odd or even channel response. • In leader mark timeslots, in the case that mid-party exchangers k=l and k=2 have been detected (SCTD is on and detected), the energy in the leader mark is calculated as:

ENTRANCE

Data

oddRxData, odd received data (after mid-batch cancellation).

evenRxData, not accepted data (after mid-batch cancellation).

oddChResp, * =<I>A™»-*',odd channel response.

jt(*)tr_ t 7Cf

evenChResp, ' ^'"•'A, non-channel responses.

cclCode(16), OVSF channelization code number of candidate codes.

The list of midpart offsets detected by the channel estimation function, which is of the form:<*>detMidList(16), the offset number (k-value) for detected midparts, 0 = no valid input.<*>detMidOffset(16), channel response offsets for detected

middle parties.

<*>nDetMid, the number of valid members in detMidList and detMidOffset. cclSprFactor( 16), scatter factors for the candidate codes.

cclAccept(16), the acceptance flags for the candidate codes.

REGULATION

KCELL, the maximum number of center part offsets for this timeslot. burstType, burst type for this time slot.

MUD_SUD indicator, indicates that MUD or SUD is active in this time slot. BeaconTSI, leader brand time slot indicator.

OUTPUTS

Data

• cclEnergy(16), the energies of the candidate codes.

Operating sequence

This function drives each DL timeslot.

Parameters

numSymbols, the number of symbols for estimating the code energy, set to 30. OVSF Codes, SF= only 16 (see Table 4).

Lf, channel response lengths (see Table 3).

CODE DETECT

Functional description

This function, which is shown in Figure 9, is performed primarily for MUD configuration. ISUD Configuration This function simply sets the formats for the SUD output. Own UE code detection is followed by other UE code detection. Own UE codes and other UE codes are "rejected" by removing them from the candidate code list. After running own UR code detection, other UE code detection and elimination of excess codes, the codes remaining on the candidate code list are running and the detected code list. If there are no remaining own UE codes (or P-CCPCH), an abort signal (S10) forms the output.

Own UE code detection.

Own UE code detection function is shown in Figure 9.

Step 1 of own UE code detection is run for each CCTrCH on the candidate code list, some of the own UE codes may be rejected.

Step S10 in own-UE code detection emits on the output side an abort signal indicating that no further processing of the time slot is required, if there are no remaining own-UE codes or P-CCPCH on the candidate code list.

Other UE code detect

The second UE code detection is shown in Figures 10A and 10B, and the arrangement of Figures 10A and 10B is shown in Figure 10.

Initially, the second UE code detection is run (only in the MUD configuration) after own UE code detection; in other UE codes is detected with a threshold based on the energies in own UE codes and attributes of the own UE CCTrCH units (S7 and S8) as shown in Figure 10A.

Then the second UE code detector will reject other UE codes if there are more than maxMudCodes codes on the candidate code list. The number of codes is reduced to maxMudCodes by eliminating weaker second-UE codes, namely at S20.

It should be noted that: Ma (S3), Mb (S10) and Mc (S12) are local variables containing maximum energies calculated from the flow chart. • Fa (S4), Fb (S9) and Fc (Sl3) are local flags indicating that respectively Ma, Mb and/or Mc have been calculated to contain valid data. • All three of the flags specified above are FALSE (Sl4), which means that there is no false knowledge that any of the own UE codes actually exist, at the maximum energy for the own UE code as a reference ("T" ) for the threshold (Sl6). Otherwise, the smallest of the available minimum energies is calculated (which could be 1, 2 or all 3 minimum values, which means Ma and/or Mb and/or Mc) used as reference ("T") (Sl5). It is recalled that Fx indicates that Mx has been calculated, where then x = {a, b, c}.

ENTRANCES

Data

cclCode( 16), OVSF channelization code number for candidate codes. cclMid( 16), mid-partition switch for candidate codes.

cclOffset( 16 ), the channel response offset for the candidate codes. cclSprFactor(l 6), the spreading factors for the candidate codes.

cclEnergy( 16 ), the energies of the candidate codes.

cclCCTrCH( 16), the CCTrCH number of detected code {0 = other UE code, 1 -

4=own UE or shared channel CCTrCH, 5=P-CCPCH}.

cclTFCIflag(16), is set if the code displays TFCI in its CCTrCH unit. tfcCodeListValid(4), is set if the received TFCI has been decoded by the fast TFCI process and is the tfcCodeList content's valid data for each CCTrCH.

fullDTXindicator(4), emitted if CCTrCH is fully DTX.

REGULATION

MUD_SUD indicator, indicates MUD or SUD active in this time slot.

OUTPUTS

Data

The detected code list is of the form:

chanCode(16), the channel error codes for detected codes, 0 = none valid

entrance.

sprFactor(16), spreading factors for detected codes.

midOffset( 16 ), channel response offsets for detected codes. chanCCTrCH( 16), the CCTrCH number of detected codes {= 0 second UE code, 1 -4=

own UE or common channel CCTrCH, 5 = P-CCPCH}.

chanTFCIflag(16), is set if the codes carry TFCI in their CCTrCH -

numCodes, the number of valid terms in chanCode, sprFactor, chanCCTrCH, chanTFCIflag and midOffset.

REGULATION

TimeslotAbort, set if no UE codes or P-CCPCH are to be demodulated and thus further processing of the timeslot is required. The end function operates during each LD time slot.

Parameters.

Two thresholds are set.

In an example, was:

eigenUE threshold factor set to 0.1.

the second UE threshold factor was set to 0.7.

• maxMudCodes, the largest number of channelization codes that MUD can support, set to 14.

• Other thresholds can be selected, if desired.

Claims (28)

1. User equipment (UE) for receiving communication channels in time frames that include several time slots, where the time slots have data signals for several channels, which user equipment includes a blind code detector to identify a channel code that is among the multiple channels that include channel codes not known in advance to the UE and to generate a list of channel code candidates from the multiple channels, which list may include own UE channel codes and other UE channel codes, and a detector which is one of a multi-user detector (MUD) and a single-user detector (SUD) to detect own UE channel code candidates and other UE channel code candidates from the list of channel code candidates, characterized in that the detector includes means for rejecting own UE channel code candidates by comparing own UE channel code candidates with a first, given energy threshold and for rejecting own UE channel code candidates with an energy that is less than the first, given threshold, and means for rejecting other UE channel code candidates by comparing other UE channel code candidates with a second given energy threshold and rejecting other UE channel code candidates having an energy less than the second given threshold. 2. UE as stated in claim 1, characterized in that the blind code detector includes a device for generating a channel code candidate list, a device for measuring channel code energy in channel codes on the channel code candidate list and a device for detecting channel codes. 3. The UE as set forth in claim 1, characterized in that it includes means for detecting midparts to create a set of channel code candidates and their associated midpart exchanges for a channel code candidate list. 4. The UE as set forth in claim 3, characterized in that on the condition that a standard midpart case occurs, in which each detected midpart explicitly indicates a set of channelization codes that may have been transmitted, or on the condition that a common midpart case occurs, in which a midpart switch is transmitted, includes the means to detect means for entering a beacon midportion into the candidate code lists with its associated channel difference code, channel response offset and spread factor in response to detection of a beacon midportion, and means for setting a flag for a beacon code to thereby prevent a beacon code from being rejected. 5. UE as set forth in claim 4, characterized in that the means for detecting, on the condition that a standard middle party case occurs, further includes means for entering a first beacon center portion into the candidate code lists with its associated channelization code, channel response offset and spread factor in response to detection of a first beacon portion, and means responsive to failure to detect the first beacon center portion, and responsive to a second beacon center portion to enter said second beacon center portion into the candidate code list with its associated channelization code, channel response offset, and spread factor in response to detection of the second beacon center portion, and means for setting a flag to prevent the beacon code of the second beacon center portion from being rejected. 6. The UE as set forth in claim 3, characterized in that it further comprises means for copying identified codes into the candidate code list together with their associated mid-part shifts, channel response shifts and spreading factors. 7. UE as specified in claim 6, characterized in that it further includes means for searching a separate UE allocation list for each candidate code, and means for responding to each candidate code contained in the own UE allocation list to add an assigned coded composite transmission channel number (CCTrCH) assigned to each own candidate UE. 8. UE as specified in claim 6, characterized in that it further comprises means for setting up a flag for own UE transmitted codes, which is known from the transport format combination indicator to thereby prevent these codes from being rejected. 9. UE as stated in claim 7, characterized in that it further includes means to delete from the candidate code list all non-transferred codes. 10. UE as stated in claim 3, characterized in that it further comprises means, on the condition that a common mid-party case occurs, to enter a beacon mid-party into the candidate code list with its assigned channelization code, channel response shift and spreading factor in response to detection of a beacon mid-party, and means for setting up a flag for the beacon code to thereby prevent this beacon code from being rejected, means for stopping the processing on the condition that a common mid-part exchange has not been detected, and means of entering into the candidate code list all remaining channelization codes together with a common mid-part exchange and a given spreading factor. 11. The UE as stated in claim 10, characterized in that it further comprises, conditional on the occurrence of a non-leader time slot, means to stop the processing on the condition that a common mid-part exchange has not been detected. 12. UE as stated in claim 3, characterized in that it further comprises means for searching a separate UE allocation list for the identification of candidate codes that are found on the allocation list as a separate UE candidate, means for copying candidates' CCTrCH numbers to the candidate code list, and means for assigning a CCTrCH number equal to zero for those candidates not found in the own UE allocation list. 13. UE as specified in claim 12, characterized in that it includes means to prevent rejection from code determination of codes that are known to have been transmitted, and means for removing from the candidate code list codes that have not been transmitted based on a Transport Format Combination Indicator (TFCI). 14. UE as specified in claim 12, characterized in that it further includes means for identifying candidate codes from the candidate list whose assigned CCTrCH is equal to zero, like other UE codes. 15. Method for receiving communications in time frames comprising multiple time slots, where these time slots comprise data signals for multiple channels, characterized in that the method comprises: detecting midparts to generate a set of channelization codes and their associated midpart exchanges for a candidate code list; identification of own UE candidate codes and their assigned parameters, and identification of other UE candidate codes and their assigned parameters, and comparison of the identified own UE codes and other UE codes with respective thresholds and acceptance of only the own UE and other UE codes UE codes that exceed their respective thresholds. 16. Method as set forth in claim 15, characterized in that for either a standard midpart case, in which each detected midpart explicitly indicates a set of channelization codes that may have been transmitted, or a common midpart case, in which a midpart switch is transmitted, further includes the detection of midsections entering only one beacon midport and one beacon code into the candidate code list with its associated channel difference code, channel response offset and spread factor in response to detection of a beacon midport with more than one code and one midport, and setting a flag for a beacon code to prevent the beacon code from being rejected. 17. Procedure as stated in claim 15, characterized in that for the standard midpart case, the detection of midparts further comprises entering a beacon midportion into the candidate code list with its associated channelization code, channel response offset and spread factor in response to detection of a first beacon midportion, and setting a flag for a first beacon code to prevent this first beacon code from being rejected. 18. Procedure as stated in claim 17, characterized in that it further comprises entering a beacon center part into the candidate code list with its associated channelization code, channel response offset and spread factor on the condition that a first beacon center part is absent and a second beacon center part is detected, and setting a flag for a second beacon code to prevent this second beacon code from being rejected. 19. Procedure as stated in claim 15, characterized in that for a standard midpart case, the detection of midparts further comprises entering a first beacon center portion into the candidate code list with its assigned channelization code, channel response shift and spread factor in response to a first beacon center portion being detected, on the condition that the midrange detection fails to report a first beacon midrange but actually reports a second beacon midrange, entering the second beacon midrange into the candidate code list with its associated channelization code, channel response offset, and spread factor in response to the second beacon midrange, and setting a flag to prevent the beacon code of the second beacon midportion from being rejected. 20. Method as stated in claim 15, characterized in that it further comprises copying identified codes into the candidate code list together with their assigned mid-part shifts, channel response shifts and spreading factors. 21. Procedure as stated in claim 15, characterized in that it further comprises searching a separate UE allocation list for each candidate code, and for each candidate code found in the separate UE allocation list, a coded composite transmission channel number (CCTrCH) associated with each separate UE candidate is added. 22. Method as specified in claim 20, characterized in that it further comprises setting up flags for own transmitted UE codes which are known from the transport format combination indicator (TFCI) to prevent these codes from being rejected. 23. Procedure as stated in claim 21, characterized in that it further comprises setting up a flag for transmitted own UE codes which will be known from the transport format combination indicator (TFCI) to prevent these codes from being rejected, and deleting from the candidate code list all non-transmitted codes. 24. Procedure as stated in claim 15, characterized in that for a common middle part case, the detection of middle parts further comprises entry of beacon midportion into the candidate code list with its associated channelization code, channel response offset and spread factor in response to a beacon midportion, and setting a flag for the beacon code to prevent the beacon code from being rejected during subsequent processing steps of the method, stopping the processing on the condition that a common mid-part exchange has not been detected, and entry on the candidate code list of all remaining channelization codes together with a common mid-part exchange and a given spreading factor. 25. Method as stated in claim 24, characterized by the fact that for a non-leader time slot, the processing is stopped on the condition that the common mid-part exchange has not been detected. 26. Method as specified in claim 16, characterized by the fact that it further includes search a separate UE allocation list that identifies candidate codes found in the allocation list as a separate UE candidate, with the CCTrCH numbers for the candidates being copied to the candidate code list, and assigning a CCTrCH number equal to zero for those candidates that have not been found in the own UE allocation list, thereby indicating that codes on the candidate code list that are not own UE codes are actually other UE codes. 27. Method as set forth in claim 26, characterized in that it further comprises, for a received transport format combination indicator (TFCI), prevention of rejection during code determination of codes that are known to have been transmitted, and removal from the candidate code list of codes that have not been transferred. 28. Procedures as specified in claim 26, characterized in that it further comprises identification of candidate codes from the candidate list, whose assigned CCTrCH is equal to zero, as other UE codes.