HK1064521B - Sub-channels for the random access channel in time division duplex - Google Patents

Description

Sub-channel of random access channel in time division duplex

(1) Field of the invention

The present invention relates to a wireless time division duplex (TDD/CDMA) communication system using code division multiple access. In particular, the invention relates to a secondary channel of the Physical Random Access Channel (PRACH) of such a system.

(2) Background of the invention

In a code division multiple access (FDD/CDMA) communication system using frequency division duplexing, such as: in a communication system proposed by the third generation partnership project (3GPP), a Physical Random Access Channel (PRACH) is used to transmit uncommon data packets and system control information from the User Equipment (UE) or User Equipment (UE) to the node-B.

In a third generation partnership project (3GPP), frequency division duplex (FDD/CDMA) communication system using code division multiple access, the Physical Random Access Channel (PRACH) is divided into ten millisecond (10ms) radio frames 22 having fifteen (15) time slots 24₁To 22₈(22) As shown in fig. 1. The radio frames 22 are numbered in sequence, such as: numbered 0 through 255 as a system frame number. In addition, these system frame numbers are repeated sequentially. The random access transmission begins at the beginning of a plurality of fully defined time intervals, denoted as access slots 26. Random access transmissions 28 from these users₁To 28₅(28) It begins in a particular access slot 26 and continues for one or more access slots 26. The transmissions are sent using a randomly selected signature associated with an Access Service Class (ASC) assigned to the user using the radio resource controller of the network.

The Physical Random Access Channel (PRACH) is used for signaling of unusual data packets and system control information, and the network uses the sub-channels of the PRACH to further distinguish User Equipment (UE) from Access Service Class (ASC). In a third generation partnership project (3GPP), frequency division duplex (FDD/CDMA) communication system utilizing code division multiple access, each subchannel is a subset of the associated total uplink transmission access channels 26, as described below.

Two consecutive radio frames 22 are combined into one access frame 20. The access frame 20 is divided into fifteen (15) access slots 26. Each access slot 26 has one period of two radio frame slots 24, as shown in fig. 1. In fig. 1, the periodicity of one radio frame 22 is indicated by a double-headed arrow. The subchannels assign the access slots 26 with time slots numbered sequentially from 0 to 11, as shown in fig. 1. After the subchannel 11 is assigned, the next access slot is repeated starting with a number 0. The numbering of the access slots 26 to subchannels is repeated every eight (8) radio frames, or every eighty milliseconds (80 ms). This repeated action may be viewed as a modulo-eight (mod 8) count of the wireless frame numbers.

In third generation partnership project (3GPP), frequency division duplex (FDD/CDMA) communication systems utilizing code division multiple access, multiple Physical Random Access Channels (PRACH) are used. Each Physical Random Access Channel (PRACH) is uniquely associated with a Random Access Channel (RACH) transport channel and is also associated with a combination of a preamble scrambling code, an available preamble signature, and an available secondary channel.

Figure 2 is an illustrative embodiment of such association. As shown in FIG. 2, this random access channel (RACH 0)30₀Will go through a coding block 31₀Is matched to this physical random access channel (PRACH 0)32₀. In the physical random access channel (PRACH 0)32₀The data received from the upper side will utilize the preamble scrambling code (0) 34₀And the appropriate leader signature 38 to transmit this data.

This physical random access channel (PRACH 0)32₀Is uniquely associated with the preamble scrambling code (0) 34₀And has three Access Service Classes (ASCs), namely: ASCO 400, ASC 1401, and ASC 2402. In this example, although the number of Access Service Classes (ASCs) is three (3), the maximum number of Access Service Classes (ASCs) may be up to eight (8). Each Access Service Class (ASC)40 will have a plurality of available secondary channels, available preamble signatures, and a persistence factor. This persistence factor is used to indicate: the persistence of this preamble signature is retransmitted after a failed access attempt. In a third generation partnership project (3GPP), frequency division duplex (FDD/CDMA) communication system utilizing code division multiple access, the maximum number of available secondary channels 36 is 12 and the maximum number of available preamble signatures 38 is 16.

In addition, this random access channel (RACH 1)30₁Then the physical random access channel (PRACH1)32 will be associated with this physical random access channel₁And (6) matching. This physical random access channel (PRACH1)32₁Is uniquely associated with the preamble scrambling code (1) 34₁And secondly the channel 36 and preamble signature 38 are divided into four Access Service Classes (ASCs), namely: ASCO 40₃、ASC1 40₄、ASC2 40₅And ASC 340₆. In addition, this random access channel (RACH 2)30₂Then the physical random access channel (PRACH2) 32 will be associated with this physical random access channel₂And (6) matching. This physical random access channel (PRACH2) 32₂Will utilize the preamble scrambling code (2) 34₂The physical random access channel (PRACH3)32 may also be provided₃The preparation is used. This physical random access channel (PRACH2) 34₂Three Access Service Classes (ASCs) may be utilized, namely: ASCO 40₇、ASC1 40₈And ASC 240₉. Due to the physical random access channel (PRACH2) and the physical random access channel (PRA)CH3) would share the preamble scrambling code, so a group that cuts off the available subchannel/available preamble signature combination would not provide the physical random access channel (PRACH2) 32₂The preparation is used. In contrast, the cut-off region would be the physical random access channel (PRACH3)32 provided₃The preparation is used.

In addition, this random access channel (RACH 3)30₃Then the physical random access channel (PRACH3)32 will be associated with this physical random access channel₃And (6) matching. This random access channel (RACH 3)30₃The preamble scrambling code (2) 34 is also used₂And using two Access Service Classes (ASCs), namely: ASCO 40₁₀And ASC 140₁₁. Access Service Class (ASC) ASCO 40₁₀And ASC 140₁₁Will contain this random access channel (RACH 2)30₂Unused sets of available secondary channels/available preamble signatures (preambergetnatures).

Since each Physical Random Access Channel (PRACH) Access Service Class (ASC)40 is uniquely associated with a preamble scrambling code 34 and a set of available preamble signatures and subchannels, the node B may be configured to determine: that one Physical Random Access Channel (PRACH)32 and Access Service Class (ASC)40 is associated with received Physical Random Access Channel (PRACH) data. Thus, the received Physical Random Access Channel (PRACH) data may be transmitted to an appropriate Random Access Channel (RACH) transport channel. In this example, although the Access Service Class (ASC)40 of each Physical Random Access Channel (PRACH)32 is segmented using the available preamble signature (preamblegnment), the Access Service Classes (ASC)40 may also be segmented using the secondary channel.

Another communication system that suggests the use of a Physical Random Access Channel (PRACH) is a Code Division Multiple Access (CDMA) communication system that uses Time Division Duplex (TDD), such as: the third generation partnership project (3GPP) proposes time division duplex (TDD/CDMA) communication systems using code division multiple access. In such Time Division Duplex (TDD) communication systems, a radio frame is divided into time slots in which user data is transferred. Each time slot is used only for transferring data for uplink or downlink transmission. In contrast, a frequency division duplex (FDD/CDMA) communication system using code division multiple access uses spectrum to divide the uplink transmission and the downlink transmission. Although the air interface and physical layers do differ between Frequency Division Duplex (FDD) and Time Division Duplex (TDD) communication systems, it is desirable that the two systems have similarities that reduce the complexity of the network layers, such as the second and third layers.

It is therefore an object of the present invention to provide a secondary channel of a Random Access Channel (RACH) in a Time Division Duplex (TDD) communication system.

(3) Summary of the invention

A Physical Random Access Channel (PRACH) of a wireless time division duplex (TDD/CDMA) communication system using code division multiple access defines a plurality of sub-channels. These sub-channels carry information between the system user and a system network. A series of radio frames has a series of downlink timeslots. For a particular slot number of the serial slot, each subchannel of the particular slot number is uniquely defined by a radio frame of the series of radio frames.

(4) Description of the drawings

FIG. 1 is a diagram illustrating access time slots and subchannels in a frequency division duplex (FDD/CDMA) communication system utilizing code division multiple access.

Fig. 2 is a block diagram illustrating a Physical Random Access Channel (PRACH) architecture for a frequency division duplex (FDD/CDMA) communication system utilizing code division multiple access.

FIG. 3 is a diagram illustrating sub-channels of a time division duplex (TDD/CDMA) communication system utilizing code division multiple access.

Fig. 4 is a block diagram illustrating a Physical Random Access Channel (PRACH) architecture for a time division duplex (TDD/CDMA) communication system utilizing code division multiple access.

Fig. 5 is a simplified diagram of a node B/base station using a Physical Random Access Channel (PRACH) in a time division duplex (TDD/CDMA) communication system utilizing code division multiple access.

(5) Detailed description of the preferred embodiments

Although the preferred embodiment of the present invention is described in conjunction with a third generation partnership project (3GPP) communication system, the Physical Random Access Channel (PRACH) sub-channel of a Time Division Duplex (TDD) communication system may be used in other types of communication systems.

Figure 3 is a diagram illustrating the subchannels of time slot 3 of a Physical Random Access Channel (PRACH) in a time division duplex (TDD/CDMA) communication system utilizing code division multiple access. Each Physical Random Access Channel (PRACH)47 is associated with a timeslot number 56 and a set of subchannels 50 and channel codes 52, as shown in fig. 4. For a particular timeslot number 56, a sub-channel 50 is uniquely associated with a radio frame 44, as indicated by the double-headed arrow. In one preferred embodiment, as shown in FIG. 3, each subchannel 50 is assigned to successive radio frames 44 in sequence. To illustrate, subchannel 0 is associated with a slot number of the jth radio frame, such as: radio frame 0 shown in fig. 4. Subchannel 1 is associated with the slot number of the (j +1) th radio frame, such as: radio frame 1 shown in fig. 4.

After n radio frames, the next n radio frames are repeatedly assigned to the same subchannel 50. For example, sub-channel 0 is assigned to the (n + j) th radio frame, such as: radio frame n shown in fig. 4. For a particular timeslot number 56, the subchannels 50 are assigned based on the system frame number, which is a repeating sequence of radio frames. A preferred method utilizes a modulus function of the System Frame Number (SFN) for the n subchannels. For the ith secondary channel, the present invention may use equation (1).

SFN mod n＝i (1)

Where mod n is a modulo n function. The preferred embodiment of the present invention uses a modulo eight (8) function as shown in equation (2).

SFN mod 8＝i (2)

Thus, as shown in FIG. 3, in the first frame 440 of slot 3, subchannel 0 may be assigned. And, in the second frame 44₁Sub-channel 1 may also be assigned, and so on, up to the eighth frame 44₇Secondary channel 7 is assigned. Preferably, the number of sub-channels is 8, 4, 2, or 1. Although fig. 3 shows only slot 3 sub-channel assignments, the same method can be applied to any slot number.

In a frequency division duplex (FDD/CDMA) communication system utilizing code division multiple access, each Physical Random Access Channel (PRACH)32 is associated with a unique combination of a preamble scrambling code (PRACH) 34, an available subchannel 36, and an available preamble signature (PRACH) 38. Fig. 4 shows a possible embodiment of four (4) Physical Random Access Channels (PRACH).

In a similar manner, each Physical Random Access Channel (PRACH)48 of a Time Division Duplex (TDD) communication system can preferably be associated with a unique combination of a time slot 56, available channel codes 50 (up to eight), and available subchannels 52 (up to eight), as shown in fig. 4. The channel codes 52 are provided for the users to use to transmit the uplink data. Similar to Frequency Division Duplex (FDD) communication systems, each Physical Random Access Channel (PRACH)48 of a Time Division Duplex (TDD) communication system is matched to the transport channel of a Random Access Channel (RACH)46 via a code block 47. Fig. 4 shows a general architecture of these Physical Random Access Channels (PRACH). Each Physical Random Access Channel (PRACH)48 is associated with a time slot 56 and a set of available subchannels 50 and available channel codes 52. As shown in fig. 4, each Physical Random Access Channel (PRACH)48 is assigned a unique channel code 52 in a particular time slot. This allows the Physical Random Access Channel (PRACH) receiver of the base station to know the channel codes 52, which are used to recover the received Physical Random Access Channel (PRACH) data, thereby distinguishing between different Physical Random Access Channels (PRACH) 48.

The Access Service Class (ASC) can preferably be formed by puncturing the available sub-channels 50 and channel codes 52 for a particular Physical Random Access Channel (PRACH). Typically, the number of Access Service Classes (ASCs) 54 will set an upper limit, such as: and eight (8). Random access channel (RACH 0)46₀The physical random access channel (PRACH O)48 is utilized₀Time slot (0) 56 for decoding appropriate channel codes₀Thereby receiving the physical random access channel (PRACH 0)48₀The data of (1). These available subchannels 50 and channel codes 52 are divided into three Access Service Classes (ASCs), namely: ASCO 54₀、ASC1 54₁、ASC2 54₂. As shown, each slice is set using a channel code 52, although in other embodiments the slices may be set based on a unique set of subchannels 36 or channel code/subchannel combinations. Thus, in the preferred embodiment, each Access Service Class (ASC)54 has a unique set of the set of channel codes 52 for the Physical Random Access Channel (PRACH) 48. An Access Service Class (ASC)54 associated with the received Physical Random Access Channel (PRACH)48 is determined using the channel code 52, which is used to recover the received Physical Random Access Channel (PRACH) data.

This random access channel (RACH 1)46₁The channel code 52 of the physical random access channel (PRACH1) is used to decode the time slot (time 1)56₁Thereby receiving the physical random access channel (PRACH1) 48₁The data of (1). The available subchannels 50 and channel codes 52 may be divided into four Access Service Classes (ASCs) 54, namely: ASCO 54₃、ASC1 54₄、ASC2 54₅And ASC354₆。

In addition, this random access channel (RACH 2)46₂The time slot (time 2)56 is decoded using the channel code 52 of the physical random access channel (PRACH2)₂Thereby receiving the physical random access channel (PRACH2) 48₂The data of (1). The available subchannels 50 and channel codes 52 may be divided into three Access Service Classes (ASCs) 54, namely: ASCO 54₇、ASC1 54₈And ASC 254₉And the physical random access channel (PRAM 3)48₃Is not utilized for cutting. In addition, this random access channel (RACH 3)46₃The channel code 52 of the physical random access channel (PRACH3) is used to decode the time slot (time 2)56₂Thereby receiving the physical random access channel (PRACH3)48₃The data of (1). The available subchannels 50 and channel codes 52 for time slot (time 2) may be divided into two Access Service Classes (ASCs) 54, namely: ASCO 54₁₀And ASC 154₁₁And the physical random access channel (PRAM 2)48₂Is not utilized for cutting. As shown in FIG. 4, the time slot (timestore 2)56₂The channel code 52 may be utilized to effectively partition into two Physical Random Access Channels (PRACH)48, namely: physical random access channel (PRACH2) 48₂And physical random access channel (PRACH3)48₃. In this example, the received data in the time slot (time 2) is then transmitted to the appropriate Physical Random Access Channel (PRACH)48 based on the channel codes used to transmit the data. Alternatively, in another embodiment, the slice may be set using subchannel 36 or a channel code/subchannel combination.

As shown in the physical example of the Physical Random Access Channel (PRACH) of fig. 4, the Physical Random Access Channel (PRACH) architecture of the Time Division Duplex (TDD) communication system is also similar to the Physical Random Access Channel (PRACH) architecture of the Frequency Division Duplex (FDD) communication system shown in fig. 2. In a Time Division Duplex (TDD) communication system, each Physical Random Access Channel (PRACH) is associated with a time slot 56. In a Frequency Division Duplex (FDD) communication system, each Physical Random Access Channel (PRACH) is associated with a preamble scrambling code 34. The Access Service Class (ASC)54 of a Time Division Duplex (TDD) communication system is preferably divisible by the available channel codes 52, while the Access Service Class (ASC)40 of a Frequency Division Duplex (FDD) communication system is preferably divisible by the available preamble signature 38. The similarity of these embodiments may enable higher layers to have a similar manner of operation between Time Division Duplex (TDD) and Frequency Division Duplex (FDD) communication systems.

Fig. 5 is a simplified block diagram illustrating a Time Division Duplex (TDD) Physical Random Access Channel (PRACH) communication system. To correlate Physical Random Access Channel (PRACH) information, such as: assigning a Physical Random Access Channel (PRACH) and an Access Service Class (ASC) from the network controller 62 to the User Equipment (UE) via the node B/base station 58, the present invention employs a Physical Random Access Channel (PRACH) information signaling device. The Physical Random Access Channel (PRACH) information signal is transmitted from an antenna 72 or antenna array through a radio channel 74 through a switching device 70 or isolation device. This transmitted signal is received using antenna 76 of User Equipment (UE) 60. The received signal passes through a switching device 78 or isolation device to a Physical Random Access Channel (PRACH) information receiver 82.

To transmit data from the User Equipment (UE)60 to the base station 58 on the Physical Random Access Channel (PRACH), a Physical Random Access Channel (PRACH) transmitter 80 uses the available code of the Physical Random Access Channel (PRACH) to spread the Physical Random Access Channel (PRACH) data 84 to the User Equipment (UE)60 and uses the Physical Random Access Channel (PRACH) time slots to multiplex the spread data. The spread data is passed through a switching device 78 or isolation device and transmitted from the antenna 76 via the wireless interface 74. The antenna 72 or antenna array of the base station 58 also receives the transmitted signal. The received signal passes through a switching device 70 or isolation device to a Physical Random Access Channel (PRACH) receiver 68. This entity random accessThe channel (PRACH) data 84 is recovered by the Physical Random Access Channel (PRACH) receiver 68 using a channel code that is spread over the PRACH data 84. The recovered Physical Random Access Channel (PRACH) data 84 is sent to a Random Access Channel (RACH) transport channel 64 associated with the PRACH₁To 64₄. In addition, the network controller 62 also provides Physical Random Access Channel (PRACH) information to the Physical Random Access Channel (PRACH) receiver 68 for recovery of the Physical Random Access Channel (PRACH) data 84.

Claims (16)

1. A method for defining subchannels of a physical random access channel of a wireless time division duplex communication system using code division multiple access, the subchannels being used by the system to distinguish between different access service classes, the method comprising the steps of:

providing a series of radio frames having a series of downlink time slots;

for a particular timeslot number of the serial timeslot, each subchannel for the particular timeslot number is uniquely defined using a radio frame of the series of radio frames.

2. The method of claim 1 wherein the number of subchannels is N, including 1, 2, 4, and 8.

3. The method of claim 2 wherein each radio frame has a system frame number.

4. The method of claim 2 wherein each subchannel is assigned to a radio frame using a modulo-N count of the system frame number.

5. A physical random access channel for use in a wireless time division duplex communication system utilizing code division multiple access, the physical random access channel comprising:

a slot number of a serial time slot uniquely associated with the physical random access channel; and

at least one sub-channel uniquely defined by a radio frame of a series of radio frames, the sub-channel being associated with the timeslot number.

6. The physical random access channel of claim 5 wherein the number of the at least one sub-channels is N, comprising: 1. 2, 4, and 8.

7. The physical random access channel of claim 6 wherein each radio frame has a system frame number.

8. The physical random access channel of claim 5 wherein each subchannel is assigned to a radio frame using a modulo-N count of the system frame number.

9. A wireless time division duplex communication system utilizing code division multiple access, the system comprising:

a network controller distinguishes user equipment by using a subchannel of a physical random access channel, the subchannel being uniquely defined by a radio frame of a series of radio frames, and the subchannel being a slot number associated with a serial slot of each radio frame.

10. The system of claim 9, further comprising:

a base station for sending access service class information to the UE, each access service class being associated with a subset of the sub-channels.

11. The system of claim 10, further comprising:

the UE receives the sending access class of service information.

12. The system of claim 11 wherein the ue utilizes the access class of service information for physical random access channel transmissions.

13. The system of claim 12 wherein the access class of service information is a channel code indicating the physical random access channel transmission.

14. The system of claim 9 wherein the number of subchannels associated with a physical random access channel is N, comprising: 1. 2, 4, and 8.

15. The system of claim 14 wherein each radio frame has a system frame number.

16. The system of claim 15 wherein each subchannel is assigned to a radio frame using a modulo-N count of the system frame number.