JPH1079970A - Radio packet channel allocating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an allocating method of a packet channel which more surely, also efficiently, dynamically and also instantly changes line exchange and a slot allocation of a packet in accordance with a occurrence of a call. SOLUTION: In radio packet communication which is one way duplex system, uses a common channel between a radio base station and plural radio packet terminals and performs radio packet communication, a radio packet terminal which is regarding to newly transmit an up packet first returns a reserving signal 2-8 in an unused up slot to a radio base station, the radio base station which receives the signal 2-8 secures plural slots over plural frames among unused up frames of frames for related up packet transfer, simultaneously transmits an enabling signal 2-9 including a secured slot number and its frequency in a down slot, and signals an up slot that permits the receiving of the signal 2-8 at the radio packet terminal and use for up packet transfer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for allocating a packet channel in TDMA (Time Division Multiple Access) wireless packet communication.

[0002]

[Prior art]

[Prior Art 1: PACS System] As a method of using a plurality of TDMA slots collectively as a packet channel, there is a PACS system in the United States. In this method, each slot is shared by circuit switching and packets, and the base station dynamically allocates each slot according to traffic. The downlink slot has a superframe structure, and a superframe header signal that broadcasts the channel configuration is transmitted at a relatively long period. This signal is used to notify the wireless terminal which slot is allocated for the packet. The terminal in the standby state can recognize the packet channel by receiving the superframe header signal.

[0003] Further, after the terminal shifts to the packet channel,
If all downlink slots are monitored and a signal indicating that the slot is a packet slot (herein, for the sake of simplicity, hereinafter referred to as a Busy / Idle signal) is included, the slot is The packet is recognized as a slot, and the packet is transmitted in the corresponding upstream slot according to the instruction of the Busy / Idle signal.

FIG. 8 shows an operation example of this method. The packet down slot (8-1) has a Busy /
Idle signal (8-5) is given. By constantly monitoring the control signal, the terminal in the communication state can recognize the packet slot set by the base station in real time. In FIG. 8, among slots 0 to 7, five slots of slots 1, 2, 5, 6, and 7 are used for packets (8
-3), and a Busy / Idle signal for random access is assigned to these slots. After confirming the downstream Idle signal in the sixth slot, the terminal transmits a request signal in the corresponding upstream sixth slot (8-6-1). After receiving the request signal, the base station changes the Busy from the sixth slot.
Signal transmission has started. Terminals are 6 (8-1-1), 7 (8-1-1)
1-2) In response to the change of the slot to Busy, a packet is transmitted in the corresponding next up sixth (8-6-2) and seventh (8-6-3) slots. Further, in the next frame, the base station performs the first (8-1-
In response to the notification of the Busy signal in the 3), 2 (8-1-4), and 5 (8-1-5) slots, the terminal receives five slots (1, 2, 5, 6, 7). Packet transfer is performed using 6-4 to 8-6-8). In the figure, 8-2, 8-4, and 8-6 represent an uplink channel, a circuit switching slot, and an uplink transmission signal, respectively.

[Prior art 2: TDD ALOHA reservation system] As shown in FIG. 9, in this system, a frame is divided into an uplink control slot (9-2), a downlink control slot (9-3), and a packet in both directions. Data transfer slot used for transfer
(9-4). Where 9-1 is the packet channel and 9-
5 and 9-6 represent downlink and uplink transmission signals, respectively.

[0006] A terminal that intends to transmit first transmits a reservation signal (9-7) in an uplink control slot, and the base station that has received the reservation signal (9-7) transmits data according to the presence or absence of another uplink packet and downlink packet. A slot for data transfer is allocated, and information on data transfer slot allocation information (9-8) is notified to each terminal in a downlink control slot. Up / down distribution is dynamically controlled. The terminal performs packet transfer in the data transfer slot of the next frame based on the notified allocation information. In this method, when transmitting uplink data over a plurality of frames, the terminal needs to transmit a reservation signal for each frame and receive allocation. In FIG. 9, one upstream packet (9-9) and one downstream packet (9-10) are transferred. This method has already been put to practical use in wireless LANs (T. Suzuki and S. Tasaka, “Contention-based res
ervation protocol using a TDD channel for wireless
local area networks ", Proc. in ICC'93, 1993).

[0007]

When multiplexing a circuit and a packet on one TDMA channel, a call-blocking rate of the circuit switching is suppressed, and when there is no circuit-switched call, a slot is allocated to the packet to enable high-speed transmission. Therefore, it is necessary to dynamically and instantaneously change the circuit switching and the packet slot assignment according to the occurrence of a call.

In order to solve this problem, in the above-mentioned prior art 1, the terminal always monitors the random access control signal in the downlink slot and detects the signal indicating the packet slot, thereby identifying the packet slot. Therefore, it is necessary for each terminal to always monitor all slots regardless of whether it is for circuit switching or packet switching, and it is not possible to determine whether a corresponding uplink slot is for packet switching or circuit switching for a slot with an incorrect downlink signal. It becomes possible.

[0009] Apart from this problem, in a system of dynamic channel allocation in which the surrounding conditions are monitored and channels used for communication in each wireless zone are selected from unused radio frequencies and slots, when interference is detected, It is necessary to immediately stop transmission on the channel receiving the interference and switch to another unused channel. In the case where only some of the slots are subject to interference, it is effective to switch only the frequency of the slot to another frequency. This control is impossible because the slot does not have a means for broadcasting information about the frequency.

[0010] Generally, in packet communication, upstream packets and downstream packets are unbalanced. In particular, in access to a WWW (World Wide Web) server or file transfer by FTP (file transfer program), a normal downstream packet is compared with an upstream packet. Traffic is 10
More than 00 times. For this reason, in order to improve the channel efficiency, the radio resources must be
A method of adaptively changing on the down stream is very effective.
In the prior art 1, since the up slot and the down slot must always be paired, such control is impossible. On the other hand, in the prior art 2, dynamic allocation of data transfer slots is performed in accordance with a reservation signal and a downlink transfer request for each frame, and dynamic uplink / downlink slot allocation according to changes in traffic becomes possible. ing. However, an uplink control slot and a downlink control slot are required for each frame, and random access is also performed on a frame-by-frame basis, which reduces channel efficiency.

An object of the present invention is to provide a packet channel allocating method which solves the above points.

[0012]

In order to solve the problems described in the preceding section, according to the present invention, for an uplink packet, a base station transmits a reservation signal from a terminal in a permission signal (claims 1 and 3). In the case of a downlink packet, it is most important to notify which slot is to be used for a packet at which frequency in a synchronization signal transmitted before the base station transmits data (claims 2 and 3). Features. At the same time, it is characterized in that a packet transfer slot is held over a plurality of frames during a period necessary for transferring the packet. This is prior art 1
Requires the terminal to determine the packet slot based on the Busy / Idle signal broadcasted for each slot, and when the prior art 2 transmits a packet to consecutive frames, a reservation / allocation operation is required for each frame. Different from doing.

[0013] This makes it possible to switch / notify the used slot every time a packet is transmitted, so that even if the downlink slot is erroneous, the packet slot does not become unusable. The frequency can be changed for each packet transmission.

Further, when TDD (Time Division Duplex) is assumed, it is possible to dynamically allocate uplink slots and downlink slots according to a reservation signal and a downlink packet arriving at a base station. Item 4), it is possible to improve channel efficiency even when uplink traffic and downlink traffic are unbalanced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of a system configuration in this embodiment. As shown here, the system consists of a radio base station (1-1) and a radio zone (1-3) formed by this radio base station.
Consisting of a plurality of wireless packet terminals (1-2)
A packet signal between each wireless packet terminal (hereinafter, terminal) and a wireless base station (hereinafter, base station) is packet-multiplexed on a packet channel commonly used among the terminals.

[First Embodiment] A first embodiment based on claims 1 to 3 will be described. FIG. 2 shows a transfer example 1 of the uplink packet in the present embodiment. As shown in this figure, in the present embodiment, the channel has a 4-channel TDMA-TDD configuration, and downlink slots 0, 1, 2, 3 (2-1) are respectively assigned to uplink slots 4, 5, 6, 7 (2-2). They are paired. Here, slots 2, 3, 6, and 7 are used by circuit switching (2-4), and the remaining slots are available for packets (2-3). Slots 0 and 4 are always set as packet slots, and their frequencies are broadcast to each terminal in control information broadcast periodically from the radio base station. The terminal that has received this control information and has shifted to the packet slot always receives this slot 0, but also receives slots other than these slots and transmits the Busy / Idle signal (2-5) as in the conventional method. It is also possible to detect and recognize the packet slot in advance. FIG. 2 shows the latter terminal. The terminal that generated the transmission data
The reservation signal (2-8) is transmitted in slot 5, which is idle. On the other hand, the base station designates slots 4 and 5 and their respective frequencies f0 and f1 in the permission signal (2-9) as the uplink packet transfer channel for the terminal. At the same time, the base station transmits the bursts in the corresponding downlink slots 0 and 1 so as not to collide with another uplink signal in the designated slot.
The sy signal is reported. The terminal receiving this is transferring uplink packet data (2-10) on the specified channel. Note that in the figure, 2-6 and 2-7 represent downlink and uplink transmission signals, respectively.

Next, FIG. 3 shows an example of transferring a downlink packet.
The channel configuration is the same as in FIG. 2, except that slots 1 and 5 are used for circuit-switched calls (3-4), and the remaining 0, 2, 3, 4, 6, and 7 are used as packet slots. Can be used (3-3). Prior to transmission of the packet, the base station which has generated the downlink packet transmits a synchronization signal (3-7) for calling the end tree to be transmitted in slot 0 where all terminals are receiving the packet, and at the same time, In the signal, the used slots 0, 2, 3 and the frequency f0,
f2 and f3 are specified. At this time, since the uplink signal can be received even while the downlink signal is being transmitted, the Busy / Idle signal (3-
5) is maintained as Idle. The terminal called by the synchronization signal receives the downlink data (3-8) at the specified slot and frequency. In FIG. 3, reference numerals 3-1 and 3-2 indicate downlink and uplink channels, respectively, and reference numeral 3-6 indicates a downlink transmission signal.

[Embodiment 2] Next, Embodiment 1 will be described as Claim 4.
A description will be given of a second embodiment in which the configurations described in above are combined. FIG. 4 shows an example of uplink packet transfer in the second embodiment. Here, as in FIG. 3, slots 1 and 5 are used for circuit switching (4-4). The terminal detecting the idle signal in slot 0 transmits the reservation signal (4-8) using the corresponding slot 4. The base station that has received this signal has slots 2, 3, 4, 6, 7 including some of the downlink slots and the frequencies f2, f3, f
0, f2, and f3 are allocated for uplink packet transfer, and such information is shown in the permission signal (4-9). At the same time, a Busy signal is broadcast in slot 0 corresponding to uplink slot 4 to prevent another terminal from transmitting an uplink signal in slot 4. The terminal receiving the permission signal transmits the uplink data (4-10) on the specified channel. In this figure, since a downlink packet occurs in the next frame, the base station transmits a synchronization signal (4-11) in usable slot 0, and transfers downlink data (4-12) using the same slot 0. Is also shown. Note that in FIG.
4-1 and 4-2 represent the downlink and uplink channels, respectively.
3 is a packet slot, 4-5 is a Busy / Idel signal, 4-6
And 4-7 represent downlink and uplink transmission signals, respectively.

FIG. 5 shows an example of downlink packet transfer in this embodiment. As in FIG. 3, the base station in which the downlink packet has occurred transmits the synchronization signal (5-8) in slot 0. At this time, since there is no request for transmission of the uplink packet, the base station transmits the slots 0, 2, 3, 4, 6, 7 including a part of the uplink slot.
And the frequencies f0, f2, f3, f0, f2, and f3 are allocated for downlink packet transfer and specified in the synchronization signal (5-8). The target terminal receives the channel specified in the synchronization signal (5-8) and receives the packet data (5-9) from the base station. At this time, Busy / Idle of slots 0, 2, and 3 corresponding to slots 4, 6, and 7 used for downlink packet transfer.
The signal (5-5) is set to Busy so that the slots 4, 6, and 7 are not used for uplink access of other terminals. When the transmission of the downlink packet is completed, the base station restarts the notification of the Idle signal in slots 0, 2, and 3 so that slots 4 to 7 can be used again as uplink slots. The terminal that has generated a transmission packet during downlink packet transfer waits until the packet data from the terminal that is communicating first ends and the packet slot changes to the Idle signal before the reservation signal (5-10) Is sent. In FIG. 5, reference numerals 5-1 and 5-2 represent downlink and uplink channels, respectively, 5-3 represents a packet slot, and 5-6 and 5-7 represent downlink and uplink transmission signals, respectively.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the operation flow of a radio base station and a terminal. FIG. 6 shows an example of an operation flow of the radio base station according to the present invention. In addition to the main flow (6-1 to 6-5), this operation flow consists of a transmission process (6-6 to 6-16) and a reception process (6-17 to 6-23) that operate independently, Slot management tasks for managing and assigning (6-
24 to 6-26). The base station constantly monitors the presence or absence of a downlink packet (6-2) and the reception of a reservation signal (6-4) in the main flow (6-1), and starts a transmission process when a downlink packet occurs (6). -3) When the reservation signal is received, the reception process (6-5) is started.

In the transmission process (6-6), if there is an untransmitted packet from the previously activated transmission process, the process waits until the transmission is completed (6-7). Call 24) (6-8). The slot management task (6-24) constantly monitors the slot allocation status and available frequencies of the channel. If this task is called, the available slots and frequencies at that time are determined by a predetermined algorithm. Assign according to (6-25). Next, when the allocated slots include the uplink slots 4 to 7 (6-9), the allocated transmission process sets the Busy in the downlink slots 0 to 3 corresponding to the uplink slots allocated in the next frame. Notify the signal (6-10). In addition, in the same frame, a synchronization signal including the information of the slot and the frequency assigned at the time of transmitting the downlink packet is transmitted (6-11). Here, the transmission of the synchronization signal is always performed in slot 0. Following the synchronization signal, the downlink packet is transmitted on the specified channel (6
-12). After the transmission is completed, the Busy notification (6-10) of the downlink slots 0 to 3 corresponding to the uplink slots 4 to 7 temporarily used for the downlink packet transfer is released and the idle notification is performed (6).
-13), enabling access to uplink signals in slots 4 to 7. On the other hand, when the uplink slots 4 to 7 are not used, there is no change in the Busy / Idle signal associated with the downlink packet transfer (6-15 to 6-16).

Next, in the receiving process (6-17), the slot management task (6-24) is called (6-18) as in the transmitting process, and
Busy notification is performed in slots 0 to 3 corresponding to the upstream slots allocated from the slot management task (6-24) (6-19)
At the same time, a permission signal including the information of the allocated slot and frequency is transmitted (6-20). Thereafter, an uplink packet transmitted from the terminal transmitted through the specified channel is received (6-21), and after the reception is completed, the slot set to Busy in step 6-19 is released and the Idle notification is returned (6-21). -twenty two).

FIG. 7 shows an example of the operation flow of the wireless packet terminal according to the present invention. The terminal always receives slot 0 (7-
2) Here, if the synchronization signal addressed to the receiving station is transmitted from the base station (7-3), the packet is received on the channel specified in the synchronization signal (7-4). On the other hand, when a transmission packet is generated (7-5), a Busy / Idle signal in a downlink slot is received, and when an Idle signal is detected (7-6), a reservation signal is transmitted in a corresponding uplink slot (7-6). -7). Here, when detecting the Idle signal, the Idle signal broadcast in slots 1 to 3 other than slot 0 may be received. After transmitting the reservation signal, if the enable signal can be received (7-8), the packet is transmitted at the slot and frequency specified in the enable signal (7-9).
If the permission signal has not been received, the reservation signal is retransmitted.

[0024]

In the radio packet channel allocating method according to the present invention, each terminal only needs to monitor one slot for transmitting the reservation signal. After the reservation is completed, even if the downlink slot is erroneous, the terminal for the packet specified by the permission signal is used. It is possible to transfer a packet using a slot and its frequency.
Even when the frequency of some slots is switched due to interference or the like, the frequency of the slot can be dynamically and instantaneously changed every time a packet is transmitted by specifying a new frequency in the permission signal and the synchronization signal. Becomes possible. Furthermore, even when a plurality of slots are used, an imbalanced allocation can be performed, and resources can be secured over a plurality of frames, so that channel efficiency and random access characteristics are improved.

[Brief description of the drawings]

FIG. 1 illustrates an example of a system configuration according to an embodiment.

FIG. 2 shows an example of uplink packet transfer according to the first embodiment.

FIG. 3 shows an example of downlink packet transfer according to the first embodiment.

FIG. 4 shows an example of uplink packet transfer according to the second embodiment.

FIG. 5 shows an example of downlink packet transfer according to the second embodiment.

FIG. 6 shows an example of an operation flow of a radio base station according to the present invention.

FIG. 7 shows an example of an operation flow of the wireless packet terminal according to the present invention.

FIG. 8 shows an operation example of the PACS method.

FIG. 9 shows an operation example of the TDD ALOHA reservation method.

[Explanation of symbols]

1-1 Wireless base station 1-2 Wireless packet terminal 1-3 Wireless zone formed by wireless base station of wireless base station 1-1 2-1, 3-1, 4-1, 5-1 and 8-1 Downlink Channels 2-2, 3-2, 4-2, 5-2, 8-2 Uplink channels 2-3, 3-3, 4-3, 5-3, 8-3 Slots for packets 2-4, 3- 4, 4-4, 5-4, 8-4 Slots for circuit switching 2-5, 3-5, 4-5, 5-5, 8-5 Busy / Idle signals 2-6, 3-6, 4- 6, 5-6, 9-5 Downlink transmission signal 2-7, 4-7, 5-7, 8-6, 9-6 Uplink transmission signal 2-8, 4-8, 5-10, 9-7 Reserved Signal 2-9, 4-9, 5-11 Permission signal 2-10, 4-10, 9-9 Up packet data 3-7, 4-11, 5-8 Synchronization signal 3-8, 4-12, 5 -9, 9-10 Downlink packet data 6-1 to 6-5 Control flow example of wireless base station (main flow) 6-6 to 6-16 Control flow example of wireless base station (transmission process) 6-17 to 6-23 Wireless base station control flow example (reception process) 6-24 to 6-26 Wireless base station control flow example (slot management task) 7-1 to 7-9 Operation of wireless packet terminal Flow Examples 9-1 above and below the packet channel 9-2 uplink control slots 9-3 downlink control slots 9-4 data transfer slots 9-8 slot allocation information

Claims (4)

[Claims] A wireless packet communication is performed between a wireless base station and a plurality of wireless packet terminals under the wireless base station using a common packet channel, and the packet channel is slotted, and a plurality of continuous slots are provided. Collectively 1
It has a frame structure as a frame, and further includes a frame (hereinafter, referred to as a downlink frame) for transferring a downlink packet from the base station to the wireless packet terminal, and a frame (for transmitting an uplink packet from the wireless packet terminal to the base station). In the wireless packet communication, which is a one-wave duplex method in which an upstream frame is multiplexed in a time-division manner within the frame, the wireless packet terminal that is to transmit a new uplink packet first uses an unused uplink slot. The radio base station, which has transmitted a reservation signal to the radio base station and received the reservation signal, assigns one or more slots from among unused uplink frames in the frame for the uplink packet transfer to one or more slots. And a permission signal including the number and frequency of the reserved slot at the same time is downloaded. Transmitting at lots radio packet channel assignment method characterized by notify the uplink slot to allow use for receiving and said uplink packet forwarding of the reservation signal to the wireless packet terminal. 2. A wireless packet communication is performed between a wireless base station and a plurality of wireless packet terminals under the wireless base station by using a common packet channel. Collectively 1
It has a frame structure as a frame, and further includes a frame (hereinafter, referred to as a downlink frame) for transferring a downlink packet from the base station to the wireless packet terminal, and a frame (for transmitting an uplink packet from the wireless packet terminal to the base station). In the wireless packet communication, which is a one-wave duplex system in which an uplink frame is multiplexed in a time-division manner within the frame, the wireless base station that wants to newly transmit a downlink packet transmits the frame for the downlink packet transfer. One or a plurality of slots are selected from the unused downlink frames, and a synchronization signal including the number and frequency of the selected slot is transmitted in the downlink slot prior to the transmission of the downlink packet. The wireless packet terminal uses one or more frames for the downlink packet transfer. Wireless packet channel assignment method characterized by notify the downlink slot. 3. A wireless packet communication is performed between a wireless base station and a plurality of wireless packet terminals under the wireless base station by using a common packet channel. Collectively 1
It has a frame structure as a frame, and further includes a frame (hereinafter, referred to as a downlink frame) for transferring a downlink packet from the base station to the wireless packet terminal, and a frame (for transmitting an uplink packet from the wireless packet terminal to the base station). In the wireless packet communication, which is a one-wave duplex method in which an upstream frame is multiplexed in a time-division manner within the frame, the wireless packet terminal that is to transmit a new uplink packet first uses an unused uplink slot. The radio base station transmits a reservation signal to the radio base station, and the radio base station receiving the reservation signal assigns one or a plurality of slots from unused uplink frames in the frame for the uplink packet transfer to one or more slots. A permission signal including the number and frequency of the reserved slot is secured at the same time over a plurality of frames. The wireless base station that transmits a downlink packet by notifying the wireless packet terminal of an uplink slot permitted to be used for receiving the reservation signal and transmitting the uplink packet, and transmitting a new downlink packet, One or more slots are selected from unused downlink frames in the frame for downlink packet transfer, and a synchronization signal including the number and frequency of the selected slot is downlinked prior to transmission of the downlink packet. A wireless packet channel allocation method, wherein the wireless packet terminal is transmitted in a slot to inform the wireless packet terminal of a downlink slot to be used over one or more frames for the downlink packet transfer in advance. 4. The radio base station according to claim 1, wherein the radio base station allocates the uplink slot and the downlink slot according to a change in a ratio of an uplink slot to a downlink slot to be allocated in the frame. 2. The wireless packet channel assignment method according to 1.