JP2001186133A - Wireless base station device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce fluctuations in ATM cells which are transmitted from a wireless base station device. SOLUTION: The wireless base station device is provided with a control means, that sets a division wireless frame period by dividing one wireless frame period by a number of immediacy communication channels with high immediacy on request, a non-immediacy storage means that temporarily stores a non- immediacy unit signal, which is a unit signal of a non-immediacy communication channel having low immediacy, a joint storage means that temporarily stores the immediacy unit signal which is a unit signal of the immediacy communication channel and the non-immediacy unit signal once stored in the non- immediacy storage means and then read by each division wireless frame period, and an interface processing means. The immediacy unit signal is assigned with priority for the one division frame period, and when there is no immediacy unit signal to be assigned, the non-immediacy unit signal read from the non- immediacy storage means is assigned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio base station apparatus, for example, a radio system for performing an ATM (asynchronous transfer mode) communication with a base station control apparatus and a radio terminal. The present invention is suitably applied to a wireless base station device that connects to a wireless system for performing the wireless communication.

[0002]

2. Description of the Related Art A conventional communication system includes a base station controller, a base station, and a mobile station as constituent elements, and a wired system for performing ATM communication between the base station and the base station controller. And a wireless system for performing wireless communication between the base station and the mobile station.

[0003] Compared to STM (synchronous transfer mode) communication, ATM communication is superior in that it can accommodate communication between terminals having greatly different communication speeds, and can accommodate communication whose communication speed varies greatly during communication. The ATM communication is adopted for the above-mentioned wired system.

In the uplink channel direction from the mobile station to the base station, a radio frame having a predetermined frame length (for example, 2.5 ms) is transmitted from the mobile station by the radio communication at the same timing for a plurality of channels (during the same radio frame period). The received base station reconfigures the ATM cell from the radio frame and transmits it to the wired system as an uplink channel signal.

[0005] One uplink channel signal usually includes an ATM.
One VC (virtual channel) in communication corresponds.

When receiving radio frames for a plurality of channels in the same radio frame period, the base station multiplexes each VC corresponding to each radio frame in accordance with traffic information and transmits the multiplexed data to a wired system. Become.

[0007] At this time, for example, the information rate of the voice information changes every radio frame cycle according to the presence or absence of voice. In traffic control at the time of transmission to the (wired system), a buffer is prepared for each VC in order to handle each channel equally and fairly according to the priority of each channel even if the information rate fluctuates. Is common.

[0008] Unbiased traffic control can be realized by controlling the timing at which ATM cells of each channel are read from the respective buffers and transmitted to the wired line.

[0009]

However, in the conventional radio base station apparatus, since information received at the same timing on the radio is multiplexed according to traffic, a large amount of information in a burst manner is transmitted to a high priority channel, for example. If this occurs, the ATM cell of the lower priority channel is assigned to the corresponding VC.
The timing read from the buffer is delayed.

In addition, the delay time is necessary because the maximum value of the fluctuation of the timing at which the ATM cell is read from the buffer of each channel having a high priority can be accumulated under the influence of the above-mentioned fluctuation of the information rate. It is larger than the minimum delay time.

In addition, since the conventional base station needs to prepare a buffer for each VC, there is a disadvantage in that the memory capacity of the buffer for transmitting the ATM cell to the wired system increases and the hardware scale increases. There was.

Further, conventionally, in addition to such a buffer in units of VC, it is necessary to equip a memory common to all VCs having a function such as speed conversion, so that an increase in hardware scale cannot be avoided.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, a radio communication is performed with a radio terminal according to a predetermined radio frame period, and a radio communication is performed with a base station controller. In the wireless base station apparatus that processes a plurality of communication channels by performing asynchronous communication using the unit signal of (1), (1) the wireless frame period is set to a number corresponding to the number of required immediate communication channels with high immediacy. And (2) a non-immediate communication channel having a lower required immediacy than the immediacy communication channel among the plurality of communication channels. Non-immediate accumulation means for temporarily accumulating the non-immediate unit signal which is the unit signal of (3); Joint storage means for temporarily storing the sex unit signal and the non-immediate unit signal once stored in the non-immediate storage means, and (4) the immediacy read from the joint storage means An interface processing means for processing the unit signal and the non-immediate unit signal for transmission to the base station controller; and (5) in one of the divided frame periods, the immediate unit signal is given priority. And when there is no immediate unit signal to be assigned, the non-immediate unit signal read from the non-immediate storage means is assigned.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (A) Embodiment The case where the radio base station apparatus of the present invention is applied to a base station (radio base station apparatus) using ATM communication on a wired line between the radio base station controller and the radio base station controller. An embodiment will be described with reference to an example.

(A-1) Configuration of the Embodiment As shown in FIG. 1, the base station 10 of the present embodiment is one component of a communication system 13 including a radio base station controller 11 and a mobile station 12. is there. Here, the radio base station controller 11 and the base station 10 are connected by a wire line EL for transmitting ATM cells, and the base station 10 and the mobile station 12 are connected by a radio line WL for transmitting a radio frame. I have. An example of the mobile station 12 may be, for example, a CDMA (Code Division Multiple Access) mobile phone.

In FIG. 1, a base station 10 includes a radio unit 14
And a wireless channel processing unit (wireless channel processing unit) 15 to 20
, A wired signal processing unit 21 and a wireless base station control unit 22.

The radio section 14 performs radio communication with the mobile station 12 at a radio frame period T, and performs ATM communication.
The transmission position is made variable in units of a division period t (t ≦ T / n, where n is a natural number corresponding to the number of immediacy channels processed by the base station 10) for each VC multiplexed by It is a part that transmits and receives between the wireless channel processing units 15 to 20.

Here, the main information U is, for example, an ITU-T
It shows a CPS packet (short packet) as shown in I363.2, and includes control information for communication control,
Corresponds to end-to-end user information.

That is, the radio unit 14 is connected to the radio line W
It has a function of performing a conversion process between a radio frame transmitted and received in L and main information U used on the left side of the radio channel processing units 15 to 20 in FIG. In the processing in the upward direction UD from the mobile station 12 to which attention is paid in the present embodiment to the radio base station controller 11 via the base station 10, the radio unit 14 includes the radio frame in the payload of the ATM cell. Main information U (1,2, ..., i, i +
1,..., M1).

The N radio channel processing units 15 to 20, which are connected to the radio unit 14 and receive the main information U, are logical components and perform signal processing on the main information U. .

Between the radio channel processing units 15 and 16, there may be one or more radio channel processing units (not shown). Similarly, between the radio channel processing units 17 and 18, and between 19 and 20, there may be one or more radio channel processing units (not shown).

Such wireless channel processing units 15 to 20
Are logically grouped. In this grouping, for example, the wireless channel processing units 15 to 16 form one group GR1, and the wireless channel processing units 17 to
19 form one group GR2, and the radio channel processing units 19 to 20 form one group GR3.

The wireless channel processing unit 1 is included in the group GR1.
The group GR2 includes 5 to 16 m1 (1 to m1) wireless channel processing units.
The group GR3 includes 18 mn (m1 + 1 to m1 + mn) wireless channel processing units. The group GR3 includes p (m1 + mn + 1 to m1 + mn + p) of the wireless channel processing units 19 to 20.
Wireless channel processing units.

Then, all the wireless channel processing units belonging to the same group, for example, in the case of the group GR1, all m1 wireless channel processing units of the wireless channel processing units 15 to 16 use one communication channel (one VC). It functions to process the main information U therein.

Therefore, for example, the radio channel processing unit 1
5 and the main information U (m1) transmitted from the wireless channel processing unit 16 can be mapped to the same ATM cell and transmitted by the processing in the wired signal processing unit 21 described later. .

In FIG. 1, the length of the main information U in the time width T direction (or t direction) corresponds to the information amount of the main information U in a unit time. Therefore, in the illustrated state, for example, the main information U (p) sent from the wireless channel processing unit 20 and the main information U (1) sent from the wireless channel processing unit 19 are sent from the wireless channel processing unit 15. The amount of information per unit time is larger than the main information U (1).

Here, the code in parentheses of the main information U is for relatively identifying the main information U in the same group, and is overlapped between different groups.

Since these are logical components, the radio channel processing units 15 to 20 need not necessarily be physically N (= m1 + mn + p) components as shown.

Therefore, the radio channel processing units 15 to 20
The signal lines connecting between the signal line and the wired signal processing unit 21 need not be N (= m1 + mn + p) signal lines as shown.

For example, an HW format in which transmission positions of channels are connected in a time-sharing manner by a time-division multiplexing HW (time-division multiplexing highway), or main information U
It is also possible to use a bus-type signal line or the like that performs contention control between the wireless channel processing units 15 to 20 and the wired signal processing unit 21 according to the presence or absence of the above.

The wired signal processing unit 21 multiplexes and separates the main information U exchanged between the N radio channel processing units 15 to 20 and the base station control unit 11, and exchanges the ATM cell with the main information U. It is a part that performs a conversion operation between them and performs signal processing.

The radio base station controller 22 provided inside the base station 10 autonomously responds to control information from the mobile station 12 or the radio base station controller 11 or to the internal state of the base station 10 itself. The wireless unit 14 and the wired signal processing unit 2
1 and the like that directly control the operation of the components inside the base station 10. The grouping of the radio channel processing units 15 to 20 is also controlled by the radio base station control unit 22.

As described above, the wire line EL is a transmission line for transmitting ATM cells. For the upstream UD, the wire line processing section 21 multiplexes the main information U with the A.
The TM cell is transmitted to the radio base station controller 11.

FIG. 2 shows a functional block configuration inside the wired line processing unit 21.

(A-1-1) Internal Configuration of Wired Line Processing Unit In FIG. 2, the wired line processing unit 21 includes a main information multiplexing unit 3
0, a non-immediate data holding buffer 31, an ATM buffer control unit 32, an ATM buffer 33, a wired line corresponding unit 34, a main information separating unit 35, and a wireless channel processing unit interface unit 36. .

Radio channel processing unit interface unit 36
Is a portion that performs signal processing between the wireless channel processing units 15 to 20 and the wired signal processing unit 21.

The main information multiplexing section 30 functions in the upstream UD, multiplexes the main information U to form a payload section of the ATM cell, and attaches a header to assemble the ATM cell.

The non-immediate data holding buffer 31 connected to the output terminal of the main information multiplexing section 30 is a buffer for temporarily storing ATM cells of a non-immediate channel whose required real-time characteristics are moderate. .

On the other hand, the ATM buffer 33 connected to the output terminal of the main information multiplexing section 30 is a buffer for temporarily storing all ATM cells transmitted in the upward UD.

The ATM cell of the immediate channel, whose required real-time property is more severe than that of the non-immediate channel, is immediately output from the main information multiplexing unit 30 to the ATM cell.
The ATM cells of the non-immediate channel are supplied to and stored in the buffer 33, and are temporarily stored in the non-immediate data holding buffer 31 and then stored in the ATM buffer 33.

The non-immediate data holding buffer 31 is also an ATM
The buffer 33 may also be a FIFO (first in first out) type memory.

The ATM buffer control unit 32 connected to the control input terminal of the main information multiplexing unit 30 and the control input terminals of the buffers 31 and 33 distributes the ATM cells of the non-immediate channel to the buffer 31 and the ATM cells of the immediate channel. This is a part for controlling the transfer of ATM cells related to the main information multiplexing unit 30, the non-immediate data holding buffer 31, and the ATM buffer 33, such as distributing cells to the buffer 33.

When there is no ATM cell to be written in the ATM buffer 33, the main information multiplexing unit 30 notifies the fact to the ATM buffer control unit 32, and the ATM buffer control unit 32 sends the non-immediate data holding buffer 32 It issues a write instruction to the ATM buffer 33. This instruction is continued until a write request to the ATM buffer 23 is issued from the main information multiplexing unit 30, and the non-immediate data holding buffer 32 divides the accumulated ATM cells during that time.
Writing to the buffer 33 is continued.

The wired line corresponding section 34 connected to the output terminal of the ATM buffer 33 sends out the ATM cells read from the ATM buffer 33 to the wired line EL in the up direction UD, and receives the ATM cells from the wired line EL in the down direction DD. A
This is a section for supplying the TM cell to the main information separation section 35.

The main information separating section 35 is connected to the wired line corresponding section 34
This is a section that separates the main information U by decomposing the downstream DD ATM cell received from the GW.

When the separated main information U is control information, control information relating to control before link establishment, such as paging, is directly supplied from the main information separation unit 35 to the radio base station control unit 22. Then, the control information on the control after the link is established may be supplied to the wireless base station control unit 22 via the wireless channel processing units 15 to 20.

The wireless base station control device 11 of FIG. 1 connected to the base station 10 (wired line corresponding unit 34) via the wired line EL enables the wireless base station controller 11 to communicate with a plurality of base stations including the base station 10. And performs ATM communication in the up and down directions, and indirectly controls each base station (mainly via the radio base station control unit (22)).

For example, when soft handoff is performed, determining the timing of starting soft handoff, determining which base station and which base station to execute the soft handoff, and the like are also performed by this base station. This is the role of the station control device 11.

Hereinafter, the operation of the present embodiment having the above configuration will be described.

(A-2) Operation of the Embodiment The radio channel processing units 15 to 20 are
Are grouped in units of VC according to the instruction from. VC
In the case of grouping VCs of 1 to VCn + q as an example,
An example of the setting is shown below.

VC1: wireless channel processing units 1, 2,.
m₁ VCi: wireless channel processing unit M_i-1+1, ..., M
_i-1+ M_i (M_i= M₁+ M₂+ ... + m_i, 1 ≦ i
≦ n) VCn: wireless channel processing unit M_n-1+1, ..., M
_n-1+ M_n VCn + 1 to VCn + q: wireless channel processing unit M_n+
1, ..., N (N = M _n+ P) Here, for example, “VC1: wireless channel processing units 1, 2, 2,
…, M₁"Indicates the same group corresponding to the virtual channel VC1.
Channel processing grouped into groups (GR1)
The units are 1 to m1, that is, the wireless channel processing units 15 to 16.
From the radio channel processing units 15 to 16
, U (1)... U (i)... U
(M1) is one AT such as the ATM cell C1 shown in FIG.
It shows that it can be mapped to M cells.

In the case of FIG. 2, the main information U (1) to U (m1)
Is large enough to be accommodated in one ATM cell, the main information U (1) to U (i) are mapped to the ATM cell C1, and the main information U (i + 1) is mapped to the ATM cell C2.
ＵU (m1) are mapped.

Here, the VC1 to which the ATM cells C1 and C2 directly output from the output terminal of the main information multiplexing unit 30 belong.
Is an immediacy channel, and the main information U (1) to U (m1) accommodated in C1 and C2 are user information of immediacy such as voice communication and an end call set for each mobile station. This is control information.

For VCi to VCn + q, VC1
Is the same as

However, it is assumed that each of the channels VC1 to VCn is an immediate channel and each of the channels VCn + 1 to VCn + q is a non-immediate channel. The non-immediate channel main information U corresponds to non-immediate user information such as e-mails and non-immediate control information.

In the period of the division period t1 shown in FIG. 2, even if the ATM cells C1 and C2 of the immediacy channel VC1 are accommodated, there is a margin of only the margin period ts1.
During s1, the ATM cell C3 stored in the non-immediate data holding buffer 31 is transmitted.

The ATM cell C3 has an immediate channel VC1.
ATM cells belonging to the non-immediate channel VCS1 which are different from the ATM cells stored in the non-immediate data holding buffer 31 and which are stored first.
Cell. Any of the channels VCn + 1 to VCn + q may correspond to the non-immediate channel VCS1.

Even when the ATM cell C3 is accommodated, there is a remaining amount enough to accommodate the ATM cell of another non-immediate channel in the allowance period ts1.
The ATM cells stored in ATM cell C3 and subsequent ATM cells in 1 (this may be the same non-immediate channel ATM cell as ATM cell C3 or another non-immediate channel ATM cell) According to the order of accumulation, they are sequentially accommodated in the margin period ts1.

In the division period t2 following t1, first, A belonging to any of the immediate channels VC1 to VCn
The TM cell C4 is output from the main information multiplexing unit 30.

In this division period t2, the same operation as in the division period t1 can be repeated.

However, if any of the immediacy channels VC1 to VCn during the division period t2,
If there is no main information U to be transmitted, the division cycle t2
From the beginning, the non-immediate channels VCn + 1 to VCn + q
Are read out from the non-immediate data holding buffer 31 in accordance with the storage order, and
The data is transmitted to the TM buffer 33.

Therefore, according to the operation of the present embodiment, the position of the frame of each channel in one cycle T of the radio frame is determined by starting from the head of the radio frame T (for example, F1 shown in FIG. 2) for each VC. The interval is set, and as described above, if i is 1 ≦ i ≦ n,
A general VCi position is represented by t · (i−1) (1).

However, non-immediate VCn + 1 to VCn + q
Can be the same frame position as any of VC1 to VCn depending on the status of the radio resource (traffic of the immediacy channel).

In order to perform the above processing, VC1
The relationship between the maximum throughput of each VC and the throughput of the wired line EL, where Bj (where j is 1 to mi) bit / s, and the throughput of the wired line EL is Abit / s, where Bj is the maximum throughput of each channel from VCn to VCn. A ≧ B1 +... + Bmi (2)

As a result, even if an ATM cell belongs to a non-immediate channel having a low priority, the maximum delay time can be transmitted to the wired line EL within the period of the division cycle t due to the effect of statistical multiplexing. As much network capacity as possible can be secured.

Also, a FIFO type ATM buffer 3
The capacity C of 3 indicates that the throughput of the wire line is Abit / s
At the time, C ≧ A · t (3)

From these equations (2) and (3),
Even if a large amount of bursty traffic occurs in the high-priority immediacy channel, each division period t (t1, t2, etc.)
In this case, a sufficient margin time ts can always be ensured, and no overflow of ATM cells occurs in the ATM buffer 33.

Even when bursty traffic occurs in any of the non-immediate channels, the division period t
Can be read from the non-immediate data holding buffer 31 without fail.

Further, when the ATM cell is stored in the ATM buffer 33, the wired line corresponding unit 34 reads the ATM cell, sends out the read ATM cell to the wired line EL, and stores the ATM cell in the ATM buffer 33. When there are no more ATM cells, an idle cell is transmitted.

For the down direction DD, the main information separation unit 3
In step 5, identification is performed in VC units, control information from the radio base station controller 11 for the base station 11 is sent to the radio base station control unit 22, and other information is further decomposed in VC units to separate each Processing unit 15-20
To send to.

(A-3) Effects of Embodiment As described above, according to this embodiment, the wireless channel is set to VC
Grouping each time and change the sending position for each division cycle t,
Resource management is performed for each ATM cell in the period of the division cycle t of the wireless channel grouped for each VC,
By transmitting the ATM cell of the non-immediate channel with a margin time generated for each division period t due to the statistical multiplexing effect,
Even for a non-immediate channel with a low priority, it is possible to reduce the ATM fluctuation time to the division period t or less.

In the present embodiment, A common to all VCs
By providing the TM buffer (33), it is not necessary to provide an ATM buffer for each VC as in the related art.

Since it is not necessary to provide an ATM buffer for each VC, the efficiency of memory use for the entire VC is increased, and the amount of memory and the scale of hardware can be reduced.

Also, rather than controlling a large number of buffers in VC units as in the conventional case, one buffer common to all VCs (two buffers including the non-immediate data holding buffer 31) is used, as in the present embodiment. Control makes the control itself easier.

Further, conventionally, a buffer for speed conversion or the like was required in addition to the buffer for each VC unit. However, since the ATM buffer (33) of the present embodiment is common to all VCs, a speed conversion function and the like are provided. It is possible to further improve the efficiency of memory use.

(D) Other Embodiments In the above-described embodiment, the base station 10 and the radio base station controller 11 use a fixed length ATM cell.
Although the TM communication is performed, a variable-length packet can be used in the present invention.

In the above embodiment, the expression (2), the expression
(3) shows sufficient conditions that can cope with a case where bursty traffic occurs in all of the immediate and non-immediate channels.

However, if there is no possibility that bursty traffic will occur simultaneously in all channels due to the configuration of the entire network (communication system), or if it occurs, the frequency of occurrence is very small, the equation (2) ,
Performance satisfying the condition (3) is excessive performance. Therefore, Expressions (2) and (3) are not satisfied, and A <B1 +.
Even in the case of + Bmi or C <At, there is a possibility that practically sufficient performance is secured and practically sufficient reliability can be obtained.

The communication partner of the wireless base station apparatus of the present invention is not limited to a mobile station, but may be a fixedly installed wireless communication apparatus.

That is, the present invention performs wireless communication with a wireless terminal according to a predetermined wireless frame period,
By performing asynchronous communication using a predetermined unit signal with the base station control device, the present invention can be widely applied to a wireless base station device that processes a plurality of communication channels.

[0081]

As described above, according to the present invention, although the hardware scale is smaller than before,
The delay time can also be reduced for transmission of a unit signal of a non-immediate communication channel having a low priority.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a communication system according to an embodiment.

FIG. 2 is a schematic diagram showing an internal configuration of a wired signal processing unit mounted on a base station in the communication system according to the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Base station (radio base station apparatus), 11 ... Radio base station control apparatus, 12 ... Mobile station, 13 ... Communication system, 14 ... Radio section, 15-20 ... Radio channel processing section, 21 ... Wired signal processing section, 22: Radio base station controller, 30: Main information multiplexing unit, 31: Non-immediate data holding buffer, 33: ATM
Buffer, 34: wired line corresponding unit, 35: main information separating unit, 36: wireless channel processing unit interface unit, T ...
Radio frame period, t, t1, t2... Division period.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K030 GA05 HA10 HB29 HC14 JL01 KA03 5K033 CC01 DA17 5K067 AA13 BB21 CC04 CC08 EE02 EE10 EE71 EE72 GG03 GG06 HH23 KK15 9A001 CC03 CC05 KZ56

Claims (1)

[Claims] 1. By performing wireless communication with a wireless terminal according to a predetermined wireless frame period, and performing asynchronous communication using a predetermined unit signal with a base station control device,
In a radio base station apparatus that processes a plurality of communication channels, a divided radio frame period is set by dividing one period of the radio frame period by a number corresponding to the number of required immediacy communication channels. A control means, and a non-immediate property for temporarily storing a non-immediate unit signal, which is a unit signal of a non-immediate communication channel having a lower required immediacy than the immediacy communication channel among the plurality of communication channels. An accumulating unit; an immediacy unit signal which is a unit signal of the immediacy communication channel and a non-immediateness unit once stored in the non-immediateness accumulating unit and read out in each of the divided radio frame periods. A joint storage unit for temporarily storing signals, and an immediate unit signal and a non-immediate unit signal read from the joint storage unit are transmitted to the base station controller. An interface processing means for processing to output the signal; and, in one of the divided frame periods, the immediacy unit signal is preferentially allocated. A radio base station apparatus to which the read non-immediate unit signal is assigned.