HK1114479B - User equipment and method for receiving data in high speed shared control channel - Google Patents

Description

User equipment and method for receiving data in high speed shared control channel

The present application is a divisional application of an invention patent application having an application date of 11/14/2003 and an application number of 02809881.1.

Technical Field

The present invention relates to the field of wireless communications. One application of the present invention is related to a downlink (downlink) signaling method using a modified cyclic redundancy check (cyclic redundancy check) for data protection and single/group UE identification.

Background

Wireless communication systems have become a link necessary in today's modern communication infrastructure. As such, it increasingly relies not only on the support of voice communications, but also on the support of data communications. Voice communications have a relatively low rate and are symmetric in upstream and downstream bandwidth and can be predicted for the amount of bandwidth required.

However, data communication may pose a difficult burden in telecommunication systems, especially in wireless telecommunication systems. First, data communication typically requires extremely high data rates. Second, the amount of bandwidth required for data-dependent applications can vary widely, from thousands of hertz to megahertz. Third, the amount of bandwidth in the upstream and downstream directions may be drastically different. For example, with typical internet browsing applications, very little data is transmitted in the upstream direction, but a very large amount of data is downloaded in the downstream direction. These factors can place significant constraints on wireless telecommunications systems.

The wideband cdma (wcdma) standard, such as the leading third generation 3G worldwide (IMT-2000) standard, supports data rates up to 2Mb/s in an indoor/outdoor environment and 384Kb/s in switched wide-area coverage (switch wide-area coverage), and supports high rate packet data and high rate circuit switched data. However, to meet the further requirements of packet data services, a substantial increase in this data rate is required, especially in the downlink. High Speed Downlink Packet Access (HSDPA) will allow WCDMA to support downlink peak data rates of about 8-10Mb/s for best effort packet data services. This rate is much higher than the 2Mb/s requirement of IMT-2000. Packet data capacity is also enhanced in terms of low delay and improved capacity.

One method of supporting data communications is to assign a dedicated channel to each User Equipment (UE). However, this results in extreme inefficiency in bandwidth usage, as such channels are typically left idle for a significant period of time.

Another method of replacing dedicated channels for each UE is the use of a high speed shared data channel and data packets. In this method, a plurality of high speed data channels are shared among a plurality of UEs. These UEs having data for transmission or reception are dynamically allocated one of the shared data channels. This leads to a more efficient use of the spectrum.

Fig. 1A-1C illustrate a process for assigning a high speed shared data channel when a base station has data waiting to be transmitted to a particular UE. Referring to fig. 1A, an associated downlink Dedicated Physical Channel (DPCH) is transmitted to each UE. The UE monitors the associated downlink DPCH and the shared control channel (SCCH-HS). When there is no data to transmit to the UE from the base station, the UE enters a standby mode from which it periodically "wakes up" in an attempt to monitor its associated downlink DPCH and SCCH-HS. This allows this UE to save on flow and battery power.

If data at the base station is ready to be transmitted to the UE, a high speed downlink shared channel (HS-DSCH) indicator (HI) is transmitted in the associated DPCH. The HI has an N-bit length indicating one of the 2N SCCH-HS shown in fig. 1B. For example, a HI of 2 bits may indicate 4 SCCH-HS, i.e., 00, 01, 10, or 11.

For example, as shown in fig. 1A, when the third channel in fig. 1B is indicated, HI is (1, 0). When a UE accesses a control channel identified by a HI, a particular SCCH-HS will direct the UE to the appropriate HS-DSCH that has been configured for the UE receiving the data. As shown in FIG. 1C, for example, the UE tunes to the HS-DSCH (001) identified by SCCH-HS (1, 0). This UE then receives the data sent for it on the HS-DSCH (001). It should be noted that the icons of fig. 1A-1C have represented an illustration of the flow of assigning the HS-DSCH, while the structure and use of the channels may differ slightly from the actual design in the HSDPA standard.

The process as described with reference to fig. 1A-1C provides an efficient method of assigning a common data channel for data transmission. Since packet data is intended to be transmitted for one or more specific UEs, UE Identification (ID) is an important parameter for transmitting signals from a base station to a UE.

There are many prior art methods for transmitting a UE ID between a base station and a UE. Referring to fig. 2A, the first method appends a UE ID to data for transmission. Such a combination is fed to a Cyclic Redundancy Check (CRC) generator, which outputs a CRC. The resulting data packet that is finally transmitted includes an X-bit data field, an M-bit UE ID, and an N-bit CRC, as shown in fig. 2B. While this provides sufficient signaling of both CRC and UE ID, it is wasteful of signaling bandwidth.

Another prior art technique, shown in fig. 3A, appends the UE ID to the data field input into the CRC generator. The CRC generator outputs a CRC. As shown in FIG. 3B, the data burst for transmission includes an X-bit data field and an N-bit CRC field. While this is also sufficient to send the UE ID and CRC between the base station and the UE, this approach is not ideal as it may only be used for a single UE identity. This approach also leads to UE complexity when there is a group of UEs that needs to be identified.

Disclosure of Invention

The invention discloses implementation methods for data-dependent downlink signaling. These embodiments disclose selectively adjusting the UE ID to produce a UE ID value, which is then modulo-2 added to the data field to produce the data mask. This data mask may then be further processed as a CRC field. The CRC field is then transmitted with a data burst (burst) to provide CRC related functionality. Another alternative embodiment discloses initializing the CRC generator with the UE identity prior to CRC generation. This implicit inclusion of the UE ID in the CRC does not require additional signaling overhead.

The present invention provides an apparatus for receiving an N-bit field and a downlink control message in a user equipment, the apparatus comprising: means for receiving the N-bit field and a downlink control message, wherein the N-bit field is generated by modulo-2 adding an N-bit cyclic redundancy check and an N-bit user equipment identity; means for determining whether the user equipment identity and the cyclic redundancy check are correct; means for forwarding the downlink control message to a media access control layer if the user equipment identity and the cyclic redundancy check are correct.

The present invention also provides a method for receiving an N-bit field and a downlink control message in a user equipment, the method comprising: receiving the N-bit field and a downlink control message, wherein the N-bit field is generated by modulo-2 adding an N-bit cyclic redundancy check to an N-bit user equipment identity; determining whether the user equipment identity and the cyclic redundancy check are correct; and forwarding the downlink control message to a media access control layer if the user equipment identity and the cyclic redundancy check are correct.

Drawings

FIGS. 1A-1C represent a prior art method for assigning a shared data channel, wherein FIG. 1A illustrates an associated downlink channel, FIG. 1B illustrates a plurality of control channels, and FIG. 1C illustrates a plurality of data channels;

FIG. 1D is a block diagram of a universal mobile telecommunications system network architecture;

FIG. 2A is a prior art user equipment identification (UE ID) specific Cyclic Redundancy Check (CRC) method;

fig. 2B illustrates a transmitted data burst including a data field, a UE ID field, and a CRC field;

FIG. 3A is a second prior art user equipment identification (UE ID) specific Cyclic Redundancy Check (CRC) method;

FIG. 3B illustrates a data burst including a data field and a CRC field being transferred;

FIG. 4A is a first embodiment of the present invention, utilizing modulo-2 addition between the UE ID and the CRC to generate a mask;

FIG. 4B is a data burst transmitted by the system of FIG. 4A, including a data field and a mask field;

FIG. 5A is a second embodiment of the present invention, including a CRC generator initialized with the UE ID;

FIG. 5B is a data burst transmitted by the embodiment of FIG. 5A, including a data field and a CRC field;

FIG. 6A is a third embodiment of the present invention, where the data field modulo 2 is added to the UE ID field and the tail is padded with 0 to generate a mask;

FIG. 6B is a fourth embodiment of the present invention, where the data field modulo 2 is added to the UE ID field and the front is padded with 0 to generate a mask;

FIG. 6C is a data burst transmitted by the embodiment of FIGS. 6A and 6B, including a data field and a CRC field;

fig. 7A is a fifth embodiment of the present invention, in which a data field modulo-2 is added to a UE ID field, the UE ID field is repeated and a truncated UE ID is padded in tail bits;

FIG. 7B is a sixth embodiment of the present invention, where the data field modulo-2 is added to the UE ID field, the UE ID field is repeated and the truncated UE ID is padded in the front bits;

FIG. 7C is a data burst transmitted by the embodiment of FIGS. 7A and 7B, including a data field and a CRC field;

FIG. 8 is a table listing all, subsets, sub-subsets and individual IDs;

fig. 9 is a flow diagram of message processing in accordance with the present invention.

Detailed Description

Preferred embodiments of the present invention will be described with reference to the accompanying drawings, wherein like reference numerals refer to like elements throughout.

Referring to fig. 1D, a Universal Mobile Telecommunications System (UMTS) network architecture used by the present invention includes a Core Network (CN), a UMTS Terrestrial Radio Access Network (UTRAN), and a User Equipment (UE). The two common interfaces are the Iu interface between the UTRAN and the core network and the radio interface Uu between the UTRAN and the UE. The UTRAN consists of a plurality of Radio Network Subsystems (RNSs). Multiple RNSs may be interconnected by an Iur interface. This interconnection allows independent procedures of the core network between different RNSs. The RNS is further divided into a Radio Network Controller (RNC) and a number of base stations (Node-B). The Node-bs are connected to the RNC via the Iub interface. One Node-B may serve one or more cells and typically serves multiple UEs. The UTRAN supports both FDD and TDD modes on the radio interface. For both modes, the same network architecture and the same protocol are used. Only the physical layer and the air interface Uu are specifically separated.

Referring to FIG. 4A, an embodiment of the present invention is shown. In this embodiment, system 100 uses data for transmission (hereinafter "data") from data field 102, CRC generator 104 (which has been initialized to 0), the generated CRC in CRC field 106 output from CRC generator 104, the UE ID from UE ID field 108, modulo-2 adder 110, and mask 112. It should be understood that in this and all embodiments, the number of bits per field is indicated on the field for illustration. However, this particular number of bits is exemplary and not intended to limit the invention.

System 100 receives the data field 102 and inputs data from data field 102 into CRC generator 104. CRC generator 104 generates CRC field 106 and outputs the CRC from CRC field 106 to a first input of modulo-2 adder 110. The UE ID from UE ID field 108 is output to a second input of modulo-2 adder 110. The CRC and UE ID are then modulo-2 added to produce a mask 112.

Preferably, the number of bits (M bits) of the UE ID field 108 is the same as the number of bits (N bits) of the CRC field 106. If M ═ N, the UE ID can be directly modulo-2 added to the CRC, as shown in fig. 4A. However, if M and N are not equal, an intermediate step is required to make them equal. If M < N, the UE ID is padded with a leading 0 or a trailing 0 to be the same as the length of the CRC. The "padded UE ID" is added N modulo 2 to CRC 106. If M > N, the least significant M-N bits will be truncated from the UE ID. The truncated UE ID is then modulo-2 added to the CRC.

Referring to fig. 4B, the generated mask 112 is appended to the data field 102 for transmission.

Referring to fig. 5A, a second embodiment of the present invention is shown. In this embodiment, system 200 uses data from data field 202, CRC generator 204, a UE ID from UE ID field 208, and generated CRC field 212. The system 200 receives a data field 202 and outputs data from the data field 202 to a CRC generator 204. This CRC generator 204 is the same type as CRC generator 104 of fig. 4A, except that CRC generator 204 is initialized with the UE ID from UE ID 208. Initialization is represented by the dashed line in fig. 5A. As is well known to those skilled in the art, a CRC generator is typically initialized to all 0's, as in the case of CRC generator 104 shown in FIG. 4A. Thus, CRC generator 204 generates a CRC based on the input data from data field 202 and the initialization of CRC generator 204 with the UE ID. Modulo-2 addition is not required in this embodiment.

Preferably, the number of bits (M bits) of the UE ID from the UE ID field 208 is equal to the size of the CRC generator 204, although this is not required. If the size (M bits) of the UE ID is smaller than the size of the CRC generator 204, the UE ID may be padded with the preceding 0 or the following 0 so that its length is equal to the size of the CRC generator 204. This "padded UE ID" may then be used to initialize CRC generator 204. Alternatively, the value in the UE ID field 208 may be loaded to initialize the CRC generator 204 and any bit positions not filled by the UE ID will be 0. If the size of the UE ID (M bits) is greater than the size of CRC generator 204, the least significant bits will be truncated from the UE ID to fit the UE ID to CRC generator 204. The truncated UE ID is then used to initialize CRC generator 204.

Referring to fig. 5B, the generated CRC field 212 is added to the data field 202 for transmission.

The second embodiment of the present invention using implicit UE ID presents simplicity and stability as it does not require the combination and disassembly of SCCH-HS and UE ID at the transmitter and receiver as required by the UE specific CRC method of the prior art and first embodiment.

Referring to fig. 6A, a third embodiment of the present invention is shown. In this embodiment, system 300 uses data from data field 302, a UE ID from UE ID field 308A, modulo-2 adder 310 and mask 311, CRC generator 304, and generated CRC field 312. System 300 receives data field 302 and inputs data from data field 302 to a first input of modulo-2 adder 310. Thus, the data from data field 302 and the UE ID from UE ID field 308A are modulo-2 added to produce mask 311. Mask 311 is input to CRC generator 304 which generates CRC field 312.

In this embodiment, the number of bits (M bits) of the UE ID field 308A must be the same as the number of bits (X bits) of the data field 302 in order to perform the modulo-2 addition. If M is equal to X, the value from the UE ID field 308A may be directly added modulo-2 to the data from the data field 302. However, if M and X are not equal, an intermediate step is required to make them equal. If M is less than X, then the UE ID is padded with X-M mantissa 0, so the value from UE ID field 308A is equal in length to data field 302. The "padded UE ID value" as shown in fig. 6A is then modulo-2 added to the data from the data field 302.

Due to the length X of the data field 302, it is not expected that M will be greater than X. However, if this happens, the least significant M-X bits are truncated from the value in the UE ID field 308A. The truncated UE ID is then modulo-2 added to the data from the data field 302.

Referring to fig. 6B, a fourth embodiment of the present invention is shown. In this embodiment, the system 301 operates in the same manner as the third embodiment of fig. 6A. The only difference in this embodiment is the method of generation of the value from the UE ID field 308B. In this embodiment, the UE ID is padded with X-M front 0, so the length of the UE ID from UE ID field 308B is equal to data field 302. This "padded UE ID value," as shown in fig. 6B, is then modulo-2 added to the data from the data field 302. It should be noted that the padding may optionally include a combination of a leading and trailing 0 (not shown) to make the UE ID length equal to the data field.

Referring to fig. 6C, a CRC field 312 generated from the system 300 of the embodiment shown in fig. 6A or a CRC 314 generated by the system 301 of the embodiment shown in fig. 6B is attached to the data field 302 for transmission. Thus, CRC fields 312 or 314 may be used and appended to data field 302.

Referring to fig. 7A, a fifth embodiment of the present invention is shown. In this embodiment, system 400 uses data from data field 402, a UE ID from UE ID field 408A, modulo-2 adder 410 and mask 411, CRC generator 404, and generated CRC field 412. System 400 receives data field 402 and inputs data from data field 402 to a first input of modulo-2 adder 410. The UE ID from UE ID field 408A is output to a second input of modulo-2 adder 410. The data from data field 402 and the UE ID from UE ID field 408A are modulo-2 added to produce mask 411. This mask 411 is input to the CRC generator 404, which generates a CRC field 412.

In this embodiment, the number of bits (M bits) of the UE ID field 408A must be the same as the number of bits of the data field 402 in order to perform modulo-2 addition. If M is equal to X, the UE ID from UE ID field 408A will be directly modulo-2 added to the data from data field 402. It is not expected that M will be greater than X due to the length of data field 402. However, if this happens, the least significant bits are truncated from the UE ID field 408A until the length of the UE ID is equal to X. This truncated UE ID is then added modulo-2 to the value from data field 402.

If the length of the UE ID is less than the data field 402, a "composite UE ID" is generated, so the value from the UE ID field 408 is equal to X. The composite UE ID is generated by repeating the UE ID multiple times until fitting into the X-bit field, then filling in the remaining tail bits with the truncated UE ID. This is represented in the UE ID field 408A of fig. 7A. The composite UE ID is then added modulo-2 to the data from data field 402.

Referring to fig. 7B, a sixth embodiment of the present invention is shown. The system 401 of this embodiment operates in the same manner as the fifth embodiment of fig. 7A. This embodiment differs only in the value from the UE ID field 408B. Although the composite UE ID is generated in the same manner as in fig. 7A, the truncated UE ID portion is added as a leading bit, as opposed to the trailing bit in the UE ID field 408A shown in fig. 7A. It should be noted that the truncated UE ID "pad" may include a combination of leading and trailing truncation bits such that the length of the UE ID is the same as the data field 402.

Referring to fig. 7C, a CRC field 412 generated from the system 400 of the fifth embodiment of fig. 7A or a CRC field 414 generated from the system 401 of the sixth embodiment of fig. 7B is attached to the data field 402 for transmission. Thus, the type of one of the CRC fields 412, 414 will be used and appended to the data field 402.

It should be noted that all of the above embodiments will be used to support multiple Identifications (IDs). The UE may need to handle message addresses at different levels: 1) a single ID for a UE, 2) an ID for a subset or group of UEs to which the UE belongs; or 3) broadcast (global ID) for all UEs in the corresponding system. For example, as shown in fig. 8, UE ID 12 is highlighted to indicate that it will be able to receive and process IDs at 4 different levels: 1) UE-specific ID (# 12); 2) a secondary subset C ID; 3) subset 2 ID; and 4) the global ID. It should be noted that alternate group identities a-E may also be generated, and thus different sets of UEs may be included. For example, group B would include all UEs represented close to group B, including UE numbers 2, 7, 12, 17, 22, and 27. Thus, any group or subgroup can be generated by specifically identifying individual UEs, as desired by the user.

To support this requirement, the transmitter generates a CRC as described in each embodiment. At the receiver, the UE processes the message and generates the expected CRC, without ID-based modification. The UE processor then modulo-2 adds the received CRC to the calculated CRC. The output generated is the ID transmitted, which may be any of the IDs described above. If the ID is not one of the IDs, the UE gives up transmission. With a CRC code of length N, the probability of undetected errors on the identified SCCH-HS is close to 2-N, in accordance with the present invention. Using a 24-bit CRC to protect data transmitted on the HS-DSCH, a 16-bit CRC to protect control information transmitted on the SCCH-HS, and assuming a false acceptance rate of 10 "3 for HI bits for non-intended UEs, the embodiments according to the invention described above will provide the following false acceptances:

P_fa＝P_faHI×P_faH×P_SDformula (1)

Wherein P is_faIs the likelihood of false acceptance; p_faPossibility of erroneous acceptance of HI as HISex; p_faH is the probability of false acceptance of SCCH-HS; and P_SDIs HS-DSCH (P)_SD) The likelihood of successful detection.

The above-described flag value of the present embodiment is used in equation (1):

P_fa＝10^-3×2^-16×2^-24＝9.1×10^-16

this reliability calculation indicates that for the same length CRC, the probability of the user delivering erroneous data to higher layers is extremely reduced.

Referring to fig. 9, a flow chart illustrates a method of processing downlink messages between a Node-B and a UE in accordance with the present invention. This method provides a general overview and should not be construed as an exhaustive description of all the detailed Medium Access Control (MAC) layers and the physical layer signaling (i.e., data packets) required to process the messages. The Node-B first generates a downlink control message in the MAC layer (step 1) and then forwards the message and the UE ID to the physical layer (step 2). The physical layer generates a CRC and applies the UE ID for forwarding the message (step 3) as a data burst. This message is then transmitted from the Node-B to the UE (step 4). At the physical layer, the UE ID and CRC are checked to determine if they are correct (step 5). If so, the message is forwarded to the MAC layer (step 6), which then processes the message further (step 7).

It should be noted that step 6 of fig. 9 includes an additional signal between the physical layer and the MAC layer, which includes a control message indicating that CRC/UE ID is valid. However, this is an optional step. In the preferred embodiment, only valid messages will be forwarded from the physical layer to the MAC layer. Thus, in the preferred embodiment, the MAC layer will assume that any message forwarded to the MAC is valid. In another alternative embodiment, an additional CRC/UE ID valid signal would be forwarded with the message as an additional acknowledgement.

The present invention has processing steps that eliminate the separate UE ID and CRC. When the two fields are combined as described above, the UE will not process any further messages until both the CRC and the UE ID (or other type of ID as shown in fig. 8) are correct.

Although the present invention has been described in terms of preferred embodiments, other modifications, which are within the scope of the invention as indicated by the appended claims, will be readily apparent to those of skill in the art.

Claims (8)

1. An apparatus for receiving an N-bit field and a downlink control message in a user equipment, the apparatus comprising:

means for receiving the N-bit field and a downlink control message, wherein the N-bit field is generated by modulo-2 adding an N-bit cyclic redundancy check and an N-bit user equipment identity;

means for determining whether the user equipment identity and the cyclic redundancy check are correct;

means for forwarding the downlink control message to a media access control layer if the user equipment identity and the cyclic redundancy check are correct.

2. The apparatus of claim 1, wherein the N-bit field is a 16-bit field.

3. The apparatus of claim 1, wherein the N-bit field and downlink control message are received in a wideband code division multiple access frequency division duplex format.

4. The apparatus of claim 1, wherein the N-bit field and downlink control message are received in a wideband code division multiple access time division duplex format.

5. A method for receiving an N-bit field and a downlink control message in a user equipment, the method comprising:

receiving the N-bit field and a downlink control message, wherein the N-bit field is generated by modulo-2 adding an N-bit cyclic redundancy check to an N-bit user equipment identity;

determining whether the user equipment identity and the cyclic redundancy check are correct; and

and forwarding the downlink control message to a media access control layer if the UE identity and the cyclic redundancy check are correct.

6. The method of claim 5, wherein the N-bit field is a 16-bit field.

7. The method of claim 5, wherein the N-bit field and downlink control message are received in a wideband code division multiple access frequency division duplex format.

8. The method of claim 5, wherein the N-bit field and downlink control message are received in a wideband code division multiple access time division duplex format.