HK1115691B - User equipment, method and equipment for use in a wideband code division multiple access (w-cdma) communications system - Google Patents

Description

User equipment, method and device for use in a wideband code division multiple access communication system

RELATED APPLICATIONS

The present application is a divisional application of the invention patent application entitled "apparatus for generating a user identification specific scrambling code for a high speed shared control channel" filed 5/2003 and filed 03810259.5.

Technical Field

The present invention relates to wireless communication systems. In particular, the present invention relates to a user equipment identification (UE ID) specific scrambling sequence for a high speed shared control channel (HS-SCCH).

Background

High Speed Downlink Packet Access (HSDPA) is proposed for wideband code division multiple access (W-CDMA) communication systems. Such High Speed Downlink Packet Access (HSDPA) provides high downlink data rates to support multimedia services.

To support such High Speed Downlink Packet Access (HSDPA), a high speed shared control channel (HS-SCCH) is used. These high speed shared control channels (HS-SCCH) are used to send the necessary control information to the User Equipment (UE). Each high speed shared control channel (HS-SCCH) has two PARTs, which are referred to as a first PART (PART I) and a second PART (PART II), respectively. The first PART (PART I) is to carry time critical information needed by the User Equipment (UE). The information includes a channelization code set and modulation type used by a high speed physical downlink shared control channel (HS-PDSCH) that carries a High Speed Downlink Packet Access (HSDPA) payload. This information is necessary to support High Speed Downlink Packet Access (HSDPA) because it uses Adaptive Modulation and Coding (AMC).

To obtain the first PART (PART I) of the information, each High Speed Downlink Packet Access (HSDPA) User Equipment (UE) monitors up to four high speed shared control channels (HS-SCCH) to obtain the information. Information of a specific User Equipment (UE) is distinguished from other User Equipments (UEs) by its user equipment identification (UE ID) specific scrambling sequence. The User Equipment (UE) processes each monitored high speed shared control channel (HS-SCCH) using its user equipment identification (UE ID) specific scrambling sequence to detect the high speed shared control channel (HS-SCCH) intended for the User Equipment (UE). After processing, the User Equipment (UE) decides to: on which high speed shared control channel (HS-SCCH) the information (if any) is carried with its scrambling sequence. The UE descrambles the information carried on PART I of its HS-SCCH.

Until recently, a user equipment identification (UE ID) of 10 bits was used as the basis for the user equipment (UE ID) specific scrambling sequence. In this example, the user equipment identification (UE ID) is converted to a 40-bit scrambling sequence. To convert the 10-bit user equipment identity (UE ID) to the 40-bit user equipment identity (UE ID) specific scrambling sequence, the 10-bit UE ID is processed by a Reed-Muller module to generate a 32-bit code. The first 8 bits of the generated code are repeatedly appended to the rear of the 32-bit code to generate a 40-bit code.

Although the user equipment identity (UE ID) length preferably extends to 16 chips, the high speed shared control channel (HS-SCCH) uses a 10-bit user equipment identity (UE ID) according to the current approach. The user equipment identity (UE ID) is converted to a 40 bit scrambling sequence. To convert the 10-bit user equipment identity (UE ID) to the 40-bit scrambling sequence, the 10-bit user equipment identity (UE ID) is processed using a Reed-Muller module to produce a 32-bit code. The first 8 bits of the generated code are repeated appended to the back of the 32-bit code to generate a 40-bit code.

To reduce the occurrence of false detection, it is desirable to have a perfect separation between the scrambling codes generated for each user equipment (UE ID). Therefore, the scrambling code can preferably be generated in an alternating manner.

Disclosure of Invention

A code is generated to scramble or descramble data associated with a high speed shared control channel (HS-SCCH) of a particular user. The subscriber identity of the particular user equipment comprises L bits. The 1/2 rate convolutional encoder processes at least the user identification bits using 1/2 rate convolutional encoding to generate the code.

According to a first aspect of the present invention, there is provided a wideband code division multiple access user equipment comprising: means for monitoring at least one high speed shared control channel; means for processing a first portion of said at least one high speed shared control channel and recovering data from the first portion, wherein said first portion has a scrambling code and the scrambling code is a 40 bit scrambling sequence generated by puncturing 8 bits of a 48 bit scrambling sequence generated by 1/2 rate convolutional encoding of a 16 bit user equipment identification of said wideband code division multiple access user equipment and 8 zero bits appended at the end of the 16 bit user equipment identification of said wideband code division multiple access user equipment.

According to a second aspect of the present invention, there is provided a method performed by a wideband code division multiple access user equipment, comprising: monitoring at least one high speed shared control channel; processing a first portion of the at least one high speed shared control channel and recovering data from the first portion, wherein the first portion has a scrambling code and the scrambling code is a 40 bit scrambling sequence generated by puncturing 8 bits of a 48 bit scrambling sequence generated by 1/2 rate convolutional encoding of a 16 bit user equipment identification of the wideband code division multiple access user equipment and 8 zero bits appended at the end of the 16 bit user equipment identification of the wideband code division multiple access user equipment.

According to a third aspect of the present invention, there is provided a wideband code division multiple access base station comprising: an input configured to accept a subscriber identity code comprising L bits; 1/2 rate convolutional encoder for processing at least the bits of the user identification code to produce a code for scrambling a high speed shared control channel; and a rate matching block for puncturing bits after generating the code, wherein the rate matched code is mixed with the encoded data and transmitted through the high speed shared control channel.

Drawings

FIG. 1A is a preferred diagram of a circuit for generating a code associated with a particular user of a high speed shared control channel (HS-SCCH);

FIG. 1B is a diagram of a rate matching module used in conjunction with FIG. 1A;

FIG. 2A is a preferred diagram of a circuit for generating a code associated with a 16-bit subscriber identity code;

FIG. 2B is a diagram of a rate matching module used in conjunction with FIG. 2A;

FIG. 3 is a simplified user equipment utilizing a UE ID specific scrambling code;

fig. 4 is a simplified base station utilizing a UE ID specific scrambling code.

Detailed Description

Although the preferred embodiment is described in detail in connection with a preferred application of the present invention for High Speed Downlink Packet Access (HSDPA) for a third generation partnership project (3 GPP) wideband code division multiple access (W-CDMA) communication system, the present invention is applicable to other types of Code Division Multiple Access (CDMA) communication systems. Fig. 1A and 1B show circuits for identifying a user equipment identity (UE ID) specific scrambling sequence. User equipment identification code (UE ID) X of length L_UEIs input to the circuit. The length L may be any length, such as: 8 bits, 10 bits, 16 bits, and so on. The user equipment identity (UE ID) X_UE={X_UE1，…，X_UELIs (d) covered withInput to the l/2 rate convolutional encoder 10 as shown in FIG. 1A. With the user equipment identification (UE ID), additional bits (such as "0") may also be appended to the end of the input string to extend the length of the input string and correspondingly the length of the output string. The use of the 1/2 rate convolutional encoder 10 provides a high level of code discrimination between output strings generated by different user equipment identification codes (UE IDs). Additionally, current third generation partnership project (3 GPP) wideband code division multiple access (W-CDMA) communication systems utilize the 1/2 rate convolutional encoder 10 to perform Forward Error Correction (FEC) techniques. Therefore, no additional hardware is required to generate the convolutional encoded User Equipment Identification (UEID) specific scrambling sequence. After encoding, based on the length of the output string, rate matching stage 12 may be added to puncture bits to obtain the desired string length.

Fig. 2A and 2B are circuits illustrating preferred user equipment identity (UE ID) -specific scrambling sequences for preferred user equipment identity (UE ID) codes of length 16 (L = 16). The 16-bit user equipment identity (UE ID) X_UE={X_UE1，…，X_UE16Is input to the 1/2 rate convolutional encoder 14 and has 8 "0" bits appended to the end of the input string. Thus, the input string is X_UE1，…，X_UE16,0,0,0,0,0,0,0,0. After processing by the rate/2 convolutional encoder 14, the output code is 48 bits long, i.e., C_UE＝{C_UE1，…，C_UE48}。

To reduce the length of the code to a preferred length of 40 bits, it is preferable to puncture 8 bits. Fig. 2B is a diagram illustrating the rate matching stage 16 in which puncturing is performed. After the rate matching stage 16, the effective length of the scrambling code is 40 bits.

Figure 4 is a diagram illustrating a simplified user equipment for descrambling a high speed shared control channel (HS-SCCH) with a user equipment identification (UE ID) specific scrambling code. The user equipment identification (UE ID) scrambling code is mixed with the receiving high speed shared control channel (HS-SCCH) by, for example, an exclusive or gate 18 to recover the encoded high speed shared control channel (HS-SCCH) data.

Figure 3 shows a simplified base station for scrambling encoded data using a user equipment identification (UE ID) specific scrambling code for transmission on the high speed shared control channel (HS-SCCH). The encoded data is mixed with a user equipment identification (UE ID) scrambling code of a particular user by, for example, an xor gate 20. The scrambled data is used to generate the high speed shared control channel (HS-SCCH) for transmission to the particular user.

Claims (5)

1. A wideband code division multiple access user equipment comprising:

means for monitoring a high speed shared control channel;

means for processing a first portion of said high speed shared control channel and recovering data from the first portion, wherein said first portion has a scrambling code and the scrambling code is a 40 bit scrambling sequence generated by puncturing 8 bits of a 48 bit scrambling sequence generated by 1/2 rate convolutional encoding of a 16 bit user equipment identifier of said wideband code division multiple access user equipment and 8 zero bits appended at the end of the 16 bit user equipment identifier of said wideband code division multiple access user equipment.

2. A method performed by a wideband code division multiple access user equipment, comprising:

monitoring a high-speed shared control channel;

processing a first portion of the high speed shared control channel and recovering data from the first portion, wherein the first portion has a scrambling code and the scrambling code is a 40 bit scrambling sequence generated by puncturing 8 bits of a 48 bit scrambling sequence generated by 1/2 rate convolutional encoding of a 16 bit user equipment identification of the wideband code division multiple access user equipment and 8 zero bits appended at the end of the 16 bit user equipment identification of the wideband code division multiple access user equipment.

3. A wideband code division multiple access base station comprising:

an input configured to accept a subscriber identity code comprising L bits;

1/2 rate convolutional encoder for processing at least the bits of the user identification code to produce a code for scrambling a high speed shared control channel; and

a rate matching block for puncturing bits after generating the code, wherein the rate matched code is mixed with the encoded data and transmitted through the high speed shared control channel.

4. The base station of claim 3, wherein the subscriber identity code comprises 16 bits.

5. The base station of claim 4, wherein the rate matching block is configured to puncture 8 bits after generating the code.