JP2001268051A - Up-link packet transmission method in multi-carrier/ds- cdma mobile communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an up-link packet transmission method in a novel multi- carrier DS-CDMA mobile communication system that can realize packet transmission at a variable transmission rate. SOLUTION: An operating frequency band is divided into n-sets (n is a natural number) of subcarrier f-fn, and the subcarriers f1-fn are furthermore used in time division. A frame (frame length is TF and in common to all the subcarriers) is set to each subcarrier. Moreover, the frame is temporally divided into F-sets (F is a natural number) of time slots TS1-TSF (one time slot length TS=TF/F). A mobile station transmits a packet in matching the timing of this time slot. The packet can be furthermore multiplexed by applying spread processing to the packet in the same time slot by different spread codes by the principle of code division (CDMA).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to an uplink packet transmission method in a DS-CDMA mobile communication system.

[0002]

2. Description of the Related Art Many new code division multiple access (CDMA) systems using multicarrier modulation have been proposed.
The multi-carrier / DS-CDMA system is one of them, and is called "Performance of ortholog."
online CDMA codes for quasi
-Synchronous communatio
n systems "(V. DaSilva, E. So
usa: Proc. of ICUPC '93, vol.
2, pp995-999, 1993).

[0003] Multi-carrier / DS-CDMA differs from single-carrier / DS-CDMA in which a CDMA signal is transmitted by one carrier, in which a radio transmission band is divided and a CDMA signal is transmitted in parallel by a plurality of subcarriers. It is.

[0004] As a result, the information transmission speed per subcarrier is reduced, and accordingly, the speed of a spread signal for generating a CDMA signal by spreading an information signal is also reduced. As a result, compared with single carrier / DS-CDMA, the chip length of the spread signal can be increased in multicarrier / DS-CDMA. As the chip length increases, the influence of the synchronization shift between spreading codes is reduced.
Taking advantage of this feature, in the above paper,
A method of applying quasi-synchronous transmission by applying DS-CDMA to communication from a mobile station to a base station in a mobile communication system has been proposed.

[0005] Performance evaluation at the link level of multi-carrier / DS-CDMA has been performed.

[0006] "On the Performance"
of Multi-carrierDS CDMA S
systems, "(S. Kondo and LB.
Milstein: IEEE Transaction
s on Communications, vol. 4
4, no. 2, pp. 238-246, Februar
y 1996), in a performance evaluation in an environment where narrowband interference exists, multi-carrier / DS-CDMA requires
It is shown that the characteristics are better than the single carrier / DS-CDMA.

[0007]

However, studies on the conventional multi-carrier / DS-CDMA system focus on performance evaluation at the link level, and how this system is applied to a mobile communication system. There is no study on whether the mobile station exchanges communication with the base station and how to transmit a control signal therefor.

[0008] Further, these studies have been made to always secure a dedicated communication channel from the start to the end of transmission when transmitting a signal from a transmitter to a receiver, as is usually used in a conventional mobile communication system. This is based on the circuit switching method.

When the amount of transmission of a signal to be transmitted is diversified, transmission efficiency is deteriorated in the circuit switching system. On the other hand, packet transmission can efficiently transmit signals with various transmission amounts. Therefore, when the transmission amount of a signal to be transmitted is diversified, packet transmission becomes effective.

Accordingly, the present invention provides a novel multi-carrier / multi-carrier system capable of realizing packet transmission at a variable transmission rate.
An object of the present invention is to provide an uplink packet transmission method in a DS-CDMA mobile communication system.

[0011]

In order to solve the above problems, the present invention employs means for solving the problems having the following features.

According to a first aspect of the present invention, there is provided an uplink packet transmission method in a multicarrier / DS-CDMA mobile communication system having n (n is a natural number of 2 or more) subcarriers. , A frame which is a delimiter at a fixed time interval is set for each of the communication channels of
The mobile station sets a time slot divided into pieces (F is a natural number of 2 or more), and the mobile station spreads a packet to be transmitted with a spreading code according to the timing of the time slot, and transmits the spread packet to the base station. It is characterized by the following.

According to a second aspect of the present invention, in the uplink packet transmission method according to the first aspect, the mobile station reserves a time slot and a spreading code for the base station when transmitting a packet. Requesting by transmitting a request packet, the base station allocates a time slot and a spreading code to the requested mobile station,
In the time slot assigned by the base station, the packet is spread by the assigned spreading code and transmitted.

According to a third aspect of the present invention, in the uplink packet transmission method of the first aspect, the mobile station does not request the base station to allocate a time slot to any one of the communication channels. And performs packet transmission by random access to the time slot.

According to a fourth aspect of the present invention, in the uplink packet transmission method according to the first aspect, the transmission rate of the mobile station is changed according to a transmission amount of a packet transmitted by the mobile station. It is characterized by doing.

According to a fifth aspect of the present invention, in the uplink packet transmission method according to the second aspect, the base station has k1 time slots for transmitting the reservation request packet (k1 is a natural number and k1 ≦ F). × n),
Further, m1 (m1
Is a natural number, m1 ≦ the total number of usable spreading codes), and the mobile station spreads the reservation request packet with one of the allocated spreading codes in the allocated time slot and transmits the packet. Features.

According to a sixth aspect of the present invention, in the uplink packet transmission method of the fifth aspect, the base station transmits the reservation request packet according to the number of reservation request packets from the mobile station in a predetermined period. The number k1 of transmission time slots is changed.

According to a seventh aspect of the present invention, in the uplink packet transmission method according to the fifth aspect, the base station transmits the reservation request packet according to the number of reservation request packets from the mobile station in a predetermined period. It is characterized in that the number m1 of spread codes for transmission is changed.

According to an eighth aspect of the present invention, in the uplink packet transmission method according to the fifth aspect, the base station transmits the reservation request packet according to the number of reservation request packets from the mobile station in a predetermined period. The number of transmission time slots k1 and the number of spreading codes m1 for transmitting the reservation request packet are changed.

According to a ninth aspect of the present invention, in the uplink packet transmission method according to the fifth aspect, the base station transmits to the mobile station when the number of reservation request packets from the mobile station in a predetermined period is large. The mobile station notifies the transmission restriction of the reservation request packet, and transmits the reservation request packet according to the restriction.

The invention described in claim 10 is the third invention.
In the above uplink packet transmission method, the base station has k2 time slots (k2 is a natural number, k2
2 ≦ F × n), and m2 (m2 is a natural number, m2 ≦ total number of usable spreading codes) spreading codes for spreading random access packets. Wherein a packet to be randomly accessed is spread and transmitted with one of the assigned spreading codes.

The invention described in claim 11 is the first invention.
0, wherein the base station changes the number k2 of random access packet transmission time slots according to the number of packets randomly accessed from the mobile station in a predetermined period. And

The invention described in claim 12 is the first invention.
0, wherein the base station changes the number m2 of spreading codes for random access packet transmission according to the number of packets randomly accessed from the mobile station in a predetermined period. And

The invention described in claim 13 is the first invention.
0, the base station, according to the number of random access packets from the mobile station in a predetermined period, the number k2 of the random access packet transmission time slots and the random access packet transmission Characterized in that the number m2 of spreading codes for use is changed.

The invention described in claim 14 is the first invention.
0, the base station notifies the mobile station of a random access packet transmission restriction when the number of random access packets from the mobile station in a predetermined period is large, and the mobile station , Random access is performed according to the restriction.

The invention described in claim 15 is the fourth invention.
In the uplink packet transmission method as described above, the base station transmits p (p is a natural number, p ≦ total number of usable spreading codes) to the mobile station according to the amount of transmission of the mobile station. It is characterized by assigning.

The invention described in claim 16 is the fourth invention.
In the above described uplink packet transmission method, the base station assigns spreading codes having different spreading factors to the mobile station according to the amount of transmission of the mobile station.

The invention described in claim 17 is the fourth invention.
In the above described uplink packet transmission method, the base station allocates q (q is a natural number, q ≦ F × n) time slots to the mobile station according to the amount of transmission of the mobile station. And

The invention described in claim 18 is the fourth invention.
In the uplink packet transmission method described above, the base station, according to the amount of transmission of the mobile station, the number of spreading codes p (p is a natural number, p ≦ total number of usable spreading codes),
The allocation is performed by changing at least two of the spreading codes having different spreading factors and the number of time slots q (q is a natural number, q ≦ F × n).

[0030]

Next, embodiments of the present invention will be described with reference to the drawings. (Channel configuration) FIG. 1 shows a multicarrier / DS-CD
FIG. 3 is a diagram illustrating an example of a channel configuration between a mobile station and a base station in the MA scheme.

The used frequency band is divided into n (n is a natural number of 2 or more) subcarriers f1 to fn. The subcarriers f1 to fn are used in a time-division manner. For this reason, a frame (which is a delimiter at fixed time intervals and has a frame length of _TF . This frame is common to all subcarriers) is set for each subcarrier. Further, this frame is temporally F (F is a natural number of 2 or more)
Are divided into time slots TS1 to TSF (one time slot length TS = _TF / F).

Therefore, in all subcarriers, F × n time slots exist in one frame.

The mobile station transmits a packet according to the timing of the time slot. In the same time slot, the packets are spread by different spreading codes, so that the packets are multiplexed based on the principle of code division (CDMA).

Therefore, in the channel configuration of FIG.
It becomes possible to simultaneously transmit a plurality of packets (the number of multiplexed spreading codes).

In the example of FIG. 1, three packets are multiplexed by CDMA in the time slot TS1 of the subcarrier f1. (Method of Reserving Time Slot and Spreading Code and Transmitting Packet) FIG. 2 is a diagram showing an example of control exchange performed between the mobile station and the base station when transmitting a packet from the mobile station to the base station. is there.

First, the mobile station transmits a reservation request packet to the base station, and requests allocation of a time slot and a spreading code for transmitting the packet (S101). In response to the allocation request from the mobile station, the base station allocates a time slot and a spreading code on the communication channel (S102), and notifies the mobile station of the result (S10).
3).

The mobile station spreads the packet in the time slot assigned by the base station and with the assigned spreading code and transmits it (S104).

[0038] Thereby, only the mobile station to which the time slot and the spreading code are assigned can perform transmission by spreading the packet using the assigned spreading code in the assigned time slot.

If many time slots or many spreading codes are allocated, many packets can be transmitted at the same time, so that the transmission amount increases.

Even when one time slot or one spreading code is allocated, the mobile station preferentially uses the allocated time slot and the allocated spreading code, and the mobile station has no information to transmit. Up to this point, if transmission can be performed periodically and reliably, a packet with a large transmission amount can be transmitted. (Random Access Without Reservation) FIG. 3 is a diagram showing an example of control exchange performed between the mobile station and the base station when transmitting a packet from the mobile station to the base station.

The mobile station transmits a packet by randomly accessing any of the time slots on the communication channel (S111).

Here, if the packet transmission succeeds, the packet transmission ends (S112: YES). When the mobile station fails (S112: NO), the mobile station again performs random access to one of the time slots on the communication channel and transmits the packet (S111).

As described above, a method in which a mobile station transmits a packet by randomly accessing any one of the time slots of a communication channel without requesting the base station to allocate a time slot, is as follows. This is suitable for transmitting a signal with a small transmission amount in a packet. (Assignment of Time Slot and Spreading Code According to Transmission Amount) FIG. 4 is performed by the mobile station and the base station to change the transmission rate according to the transmission amount of the packet to be transmitted by the mobile station. It is a figure showing an example of control exchange.

The mobile station first transmits a reservation request packet to the base station, requests allocation of a time slot and a spreading code, and also transmits the amount of transmission (S12).
0).

The base station allocates a time slot or a spreading code to a communication channel in accordance with the transmission amount of the mobile station based on the allocation request from the mobile station and information on the transmission amount, and transmits the result to the mobile station. Notification is made (S121).

The mobile station performs packet transmission based on the notification result (S122).

With this, if the transmission amount of the packet transmitted by the mobile station is large, the base station can transmit the large amount of transmission time slots (for example, a plurality of time slots).
And a spreading code (for example, a plurality of spreading codes, a spreading code with a small spreading factor) is allocated, and if the amount of transmission required by the mobile station is small, the base station allocates a time slot and a spreading code corresponding to that. Do.

Thus, the base station adaptively allocates time slots and spreading codes according to the transmission amount of the mobile station.

On the other hand, the mobile station can obtain a transmission rate according to the amount of transmission. (Assignment of Time Slot and Spreading Code for Reservation Request Packet Transmission) Next, when the mobile station transmits a reservation request packet to the base station, how the base station transmits the time slot and the spreading code for the reservation request packet A description will be given of whether codes are assigned. As shown in FIG. 1, simultaneous transmission of a plurality of packets of F × n × (the number of multiplexed spreading codes) from the mobile station to the base station becomes possible.

In the present invention, some of the F × n × (the number of spread code multiplexes) are used for reservation request packet transmission.

FIG. 5 shows that, from among F × n time slots existing in one frame, the base station selects any k1 (k1: natural number,
k1 ≦ F × n). Then, in the reservation request packet transmission time slot, the mobile station sets one of m1 (m1: natural number, m1 ≦ total number of usable spreading codes) predetermined by the base station.
Then, the reservation request packet is spread and transmitted.

In FIG. 5, the time slot TS1 of the subcarrier f1 and the time slot TS1 of the subcarrier f2
1, a time slot TS2 of the subcarrier f3 and the like are allocated as a reservation request packet transmission time slot.

In the case of FIG. 6, in all subcarriers,
An example of a channel configuration when a time slot of a time slot TS1 generated for each frame is set as a reservation request packet transmission time slot (k1 = n) is shown.

FIG. 6 shows a case where the time slot of the time slot TS1 is set as the reservation request packet transmission time slot in all the subcarriers f1 to fn.

In the case of FIG. 7, in all subcarriers,
An example of a channel configuration when a part of the time slot TS1 is set as a reservation request packet transmission time slot (k1 <n) is shown. The method of selecting the k1 time slots may be to assign subcarriers continuously or discretely.

In FIG. 7, the time slot TS1 of the subcarrier f3 is not assigned as a reservation request packet transmission time slot.

FIG. 8 shows an example of a channel configuration when all time slots of one subcarrier are set as reservation request packet transmission time slots (k1 = F). The number of subcarriers for setting the reservation request packet transmission time slot may be two or more.

In FIG. 8, all time slots of the subcarrier f1 are allocated as reservation request packet transmission time slots.

FIG. 9 shows an example of the channel configuration when a part of the time slots of one subcarrier is set as the reservation request packet transmission time slot (k1 <F). How to choose k1 time slots
Time slots may be allocated continuously or discretely.

In FIG. 9, TS1, T of subcarrier f1
Time slots such as S2 and TS4 are allocated as reservation request packet transmission time slots. (Change of the Number of Time Slots and Number of Spreading Codes for Transmission of Reservation Request Packet) If the number of reservation request packets from a mobile station in a predetermined period is large, the reservation request may not be responded to. Therefore, the number of time slots and the number of spreading codes for transmitting the reservation request packet are changed according to the number of reservation request packets.

In the case of FIG. 10, the base station changes the number k1 of reservation request packet transmission time slots (k1: natural number, k1 ≦ F × n) according to the number of reservation request packets from the mobile station in a predetermined period. FIG. 6 is a diagram showing an example of control performed by the base station at the time.

[0062] The base station measures the number of reservation request packets transmitted from the mobile station for a certain period of time (S130).

As a result of the measurement, if the number of reservation request packets is equal to or larger than a certain threshold value (S131: YES), the number of transmission slots of the reservation request packet is increased and the position of the time slot is notified to the mobile station (S133). .

As a result of the measurement, if the number of reservation request packets is less than a certain threshold value (S132: YES), the number of reservation request packet transmission slots is reduced, and the position of the time slot is notified to the mobile station ( S134).

If the number of reservation request packets is not equal to or greater than a certain threshold value (S131: NO), and if the number of reservation request packets is not equal to or less than a certain threshold value (S132: NO), the number of reservation request packet transmission slots is changed. do not do.

The mobile station transmits a reservation request packet according to the position of the reservation request packet transmission time slot notified from the base station.

FIG. 11 shows that, according to the number of reservation request packets from a mobile station in a predetermined period, the base station sets the number m1 (m1: natural number, m1 ≦ m) of spreading codes for transmitting reservation request packets.
FIG. 9 is a diagram illustrating an example of control performed in the base station when changing the total number of usable spreading codes).

The base station measures the number of reservation request packets transmitted from the mobile station for a certain period of time (S140).

As a result of the measurement, if the number of reservation request packets is equal to or greater than a certain threshold value (S141: YES), the number m1 of spreading codes for spreading the reservation request packet is increased, and the type is notified to the mobile station (S143). ).

As a result of the measurement, when the number of reservation request packets is equal to or smaller than a certain threshold value (S142: YES), the number m1 of spreading codes for spreading the reservation request packets is reduced,
The type is notified to the mobile station (S144).

If the number of reservation request packets is not equal to or greater than a certain threshold value (S141: NO), and if the number of reservation request packets is not equal to or less than a certain threshold value (S142: NO), a spreading code for spreading the reservation request packet Do not change the number.

The mobile station selects one of the spread codes for transmitting the reservation request packet notified from the base station, and spreads and transmits the reservation request packet.

FIG. 12 shows that, according to the number of reservation request packets from a mobile station in a predetermined period, the base station sets the number k1 (k1: natural number,
FIG. 9 is a diagram illustrating an example of control performed in the base station when changing k1 ≦ F × n) and the number m1 (m1: natural number, m1 ≦ total number of usable spreading codes) of spreading codes for transmitting a reservation request packet. is there.

The base station measures the number of reservation request packets transmitted from the mobile station for a certain period of time (S150).

As a result of the measurement, if the number of reservation request packets is equal to or greater than a certain threshold value (S151: YES), “increase the number m1 of spreading codes for spreading reservation request packets” or “ "Increase" or "increase both" and notify the mobile station of the information (S153).

As a result of the measurement, if the number of reservation request packets is less than a certain threshold (S152: YES),
"Reduce the number m1 of spreading codes for spreading reservation request packets"
Alternatively, the number of reservation request packet transmission slots k1 is reduced or both are reduced, and the information is notified to the mobile station (S154).
1: NO), and when the number of reservation request packets is not less than a certain threshold value (S152: NO), the "number of spreading codes for spreading the reservation request packet" and the "number of reservation request packet transmission slots" are not changed.

The mobile station selects one of the position of the reservation request packet transmission time slot notified from the base station and the spreading code for transmitting the reservation request packet, and spreads and transmits the reservation request packet. .

FIG. 13 shows that when the number of reservation request packets increases, the transmission of the reservation request packet may not be transmitted properly. Therefore, the base station restricts the transmission of the reservation request packet to the mobile station (for example, FIG. 9 is a diagram illustrating an example of control performed by a base station when a transmission of a reservation request packet is restricted in accordance with the restriction by restricting transmission of a packet temporally.)

The base station measures the number of reservation request packets transmitted from the mobile station for a certain period of time (S160).

As a result of the measurement, if the number of reservation request packets is equal to or larger than a certain threshold value (S161: YES), the transmission limit of the reservation request packet is made stricter than the current state, and the mobile station is notified (S163).

As a result of the measurement, if the number of reservation request packets is less than a certain threshold (S162: YES),
Restriction on transmission of reservation request packet
The mobile station is notified (S164).

If the number of reservation request packets is not equal to or greater than a certain threshold value (S161: NO), and if the number of reservation request packets is not equal to or less than a certain threshold value (S162: NO), the transmission restriction is not changed. (Assignment of Number of Time Slots and Number of Spreading Codes for Random Access) The base station assigns k2 (k2: natural number, k2 ≦ F × n) as time slots in which the mobile station can perform random access and transmit packets. further,
M2 (m
2: a natural number, m2 ≦ the total number of usable spreading codes).

In the assigned time slot, the mobile station spreads and transmits a packet to be randomly accessed with one of the assigned spreading codes.

As shown in FIG. 14, out of the F × n time slots existing in one frame, the base station determines that any k2 random access packet transmission time slots (k2: natural number, k2 ≦ F × n). The mobile station spreads the random access packet with one of m2 (m2: natural number, m2 ≦ total number of usable spreading codes) predetermined by the base station in the random access packet transmission time slot. To transmit.

In FIG. 14, the time slot TS1 of the subcarrier f1 and the time slot TS1 of the subcarrier f2
1. The time slot TS2 of the subcarrier f3 and the like are allocated as random access packet transmission time slots.

FIG. 15 shows an example of the channel configuration in the case where the time slot of the time slot TS1 generated for each frame in all subcarriers is set as a random access packet transmission time slot (k2 = n).

In FIG. 15, time slots TS1 of all subcarriers are allocated as random access packet transmission time slots.

FIG. 16 shows that in some subcarriers,
An example of a channel configuration when a time slot of a time slot TS1 generated for each frame is set as a random access packet transmission time slot (k2 <n) is shown. Regarding how to select the k2 time slots, subcarriers may be allocated continuously or discretely.

In FIG. 16, the time slot TS1 of the subcarrier f3 is not allocated as a random access packet transmission time slot.

FIG. 17 shows an example of the channel configuration when all the time slots of one subcarrier are set as random access packet transmission time slots (k2 = F).

In FIG. 17, all time slots of subcarrier f1 are allocated as random access packet transmission time slots.

FIG. 18 shows an example of a channel configuration when a part of time slots of one subcarrier is set as a random access packet transmission time slot (k2 <F).

In FIG. 18, the time slots TS1, TS2, TS4, etc. of the subcarrier f1 are allocated as random access packet transmission time slots.

The k2 time slots may be selected either continuously or discretely. (Changes in the number of random access packet transmission time slots and the number of spreading codes, etc.) If the number of random access packets from a mobile station within a predetermined period is large, communication may not be possible. Therefore, the number of random access packet transmission time slots and the number of spreading codes are changed according to the number of random access packets within a predetermined period.

In the case of FIG. 19, according to the number of random access packets from a mobile station in a predetermined period, the base station determines the number k of random access packet transmission time slots.
FIG. 6 is a diagram illustrating an example of control performed in the base station when changing 2 (k2: natural number, k2 ≦ F × n).

The base station measures the number of random access packets transmitted from the mobile station for a certain period of time (S23).
0).

As a result of the measurement, if the number of random access packets is equal to or greater than a certain threshold (S231: YES),
Increase the number of random access packet transmission slots,
The mobile station is notified of the time slot position (S23).
3).

As a result of the measurement, when the number of random access packets is less than a certain threshold (S232: YE
In S), the number of random access packet transmission slots is reduced, and the position of the time slot is notified to the mobile station (S234).

The number of random access packets is not above a certain threshold (S231: NO), and the number of random access packets is not below a certain threshold (S232:
In the case of NO), the number of random access packet transmission slots is not changed.

The mobile station transmits a random access packet according to the position of the random access packet transmission time slot notified from the base station.

FIG. 20 shows that, according to the number of random access packets from a mobile station in a predetermined period, the base station sets the number m2 (m
FIG. 5 is a diagram illustrating an example of control performed by the base station when changing (2: natural number, m2 ≦ total number of usable spreading codes).

The base station measures the number of random access packets transmitted from the mobile station for a certain period of time (S24).
0).

As a result of the measurement, if the number of random access packets is equal to or larger than a certain threshold (S241: YES),
The number m2 of spreading codes for spreading the random access packet is increased, and the type is notified to the mobile station (S243).

As a result of the measurement, when the number of random access packets is less than a certain threshold (S242: YE
S) reduces the number m2 of spreading codes for spreading the random access packet, and notifies the type to the mobile station (S2).
44).

The number of random access packets is not above a certain threshold (S241: NO), and the number of random access packets is not below a certain threshold (S242:
In the case of NO), the number of spreading codes for spreading the random access packet is not changed.

The mobile station selects one of the spreading codes for random access packet transmission notified from the base station and spreads and transmits the random access packet.

FIG. 21 shows that, according to the number of random access packets from a mobile station in a predetermined period, the base station determines the number k2 of the random access packet transmission time slots.
(K2: natural number, k2 ≦ F × n) and the number m2 of spreading codes for random access packet transmission (m2: natural number,
FIG. 9 is a diagram illustrating an example of control performed by the base station when changing (m2 ≦ total number of usable spreading codes).

The base station measures the number of random access packets transmitted from the mobile station for a certain period of time (S25).
0).

As a result of the measurement, if the number of random access packets is equal to or greater than a certain threshold (S251: YES),
"Number of spreading codes m2 for spreading random access packets
Increase ”or“ increase the number k2 of random access packet transmission slots ”or“ increase both ”,
The information is notified to the mobile station (S253).

As a result of the measurement, if the number of random access packets is less than a certain threshold (S252: YE
S) "reduces the number m2 of spreading codes for spreading random access packets", "reduces the number k2 of transmission slots for random access packets" or "reduces both", and notifies the mobile station of the information (S254). If the number of random access packets is not equal to or greater than a certain threshold (S251: NO) and the number of random access packets is not equal to or less than a certain threshold (S252: NO), "the number of spreading codes for spreading random access packets" And "number of random access packet transmission slots"
Does not change.

[0111] The mobile station selects one of the position of the random access packet transmission time slot notified from the base station and the spreading code for random access packet transmission, and spreads and transmits the random access packet. .

FIG. 22 shows that if the number of random access packets increases, the random access packet may not be transmitted properly, so the base station restricts the transmission of the random access packet to the mobile station (for example, the FIG. 6 is a diagram illustrating an example of control performed by a base station when a mobile station transmits a random access packet according to the restriction.

The base station measures the number of random access packets transmitted from the mobile station for a certain period of time (S26).
0).

As a result of the measurement, when the number of random access packets is equal to or more than a certain threshold (S261: YES),
The transmission restriction of the random access packet is made stricter than the current state, and the transmission is notified to the mobile station (S263).

As a result of the measurement, when the number of random access packets is less than a certain threshold (S262: YE
In S), the transmission restriction of the random access packet is made gentler than the current state, and the transmission is notified to the mobile station (S264).

The number of random access packets is not above a certain threshold (S261: NO), and the number of random access packets is not below a certain threshold (S262:
In the case of NO), the transmission restriction is not changed. (Change of transmission speed according to transmission amount) In the present invention, the transmission speed of the mobile station is changed according to the transmission amount of the packet transmitted by the mobile station. Hereinafter, a mode of changing the transmission rate according to the transmission amount will be described.

FIG. 23 shows, as an example, a situation in which the mobile station 1 realizes a transmission rate p times that of the mobile station 2 by multiplexing and transmitting packets using p spreading codes. Is shown.

FIG. 24 shows that the base station assigns a spreading code having a different spreading factor to a mobile station in one time slot TS of a communication channel according to the size of the transmission amount of the mobile station. FIG. 3 is a diagram showing an example of realizing.

In FIG. 24, the packet of mobile station 1 is spread by a spreading code having a spreading factor of 1 / SF times the spreading code used for the packet of mobile station 2, and the transmission speed of mobile station 1 is reduced. SF times compared to 2 (tip rate is constant)
Is shown.

FIG. 25 shows a case where the base station gives the mobile station arbitrary q (q: natural number, q ≦ F × n) times in one frame of the communication channel according to the amount of transmission of the mobile station. FIG. 5 is a diagram illustrating an example of realizing a variable transmission rate by allocating slots.

FIGS. 26, 27, 28 and 29 show that the base station determines the number of spreading codes p, spreading codes of different spreading factors and number of time slots q according to the amount of transmission of the mobile station. FIG. 8 is a diagram for describing an embodiment in which at least two are changed and assigned.

In FIG. 26, as compared with FIG. 24, the mobile station 1 further adds 1 / SF to the spreading factor of the spreading code of the mobile station 2.
By allocating p spreading codes having a double spreading factor, the transmission speed of the mobile station 1 is set to p × SF times the mobile station 2.

In FIG. 27, the transmission rate of mobile station 1 is p × q times that of mobile station 2 by assigning p spread codes to each time slot of mobile station 1 as compared with FIG. Is set to

In FIG. 28, as an example, a spreading code having a spreading factor of 1 / SF times the spreading factor of the spreading code of mobile station 2 is allocated to mobile station 1, and a time slot is further allocated by q times. , The transmission speed of the mobile station 1 is set to q × SF times that of the mobile station 2.

In FIG. 29, as an example, q times timeslots of mobile station 2 are assigned to mobile station 1 and each time slot of mobile station 1 is divided by 1 / the spread rate of the spreading code of mobile station 2. By allocating p spreading codes having a spreading factor of SF times, the transmission speed of the mobile station 1 is set to p × q × SF times the mobile station 2.

The multicarrier / DS-CDM of the present invention
If the packet transmission method of A is used, it becomes possible to realize packet transmission of a time slot reservation type, packet transmission of a random access type, and packet transmission of a variable transmission rate, and efficiently transmit signals of various transmission amounts. Can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a channel configuration between a mobile station and a base station in a multicarrier / DS-CDMA system.

FIG. 2 is a diagram (part 1) illustrating an example of control exchange performed between the mobile station and the base station when transmitting a packet from the mobile station to the base station.

FIG. 3 is a diagram (part 2) illustrating an example of control exchange performed between the mobile station and the base station when transmitting a packet from the mobile station to the base station.

FIG. 4 is a diagram (part 3) illustrating an example of control exchange performed between the mobile station and the base station when transmitting a packet from the mobile station to the base station.

FIG. 5 is a diagram (part 1) for explaining allocation of a reservation request packet transmission slot;

FIG. 6 is a diagram (part 2) for explaining allocation of a reservation request packet transmission slot.

FIG. 7 is a diagram (part 3) for explaining allocation of a reservation request packet transmission slot;

FIG. 8 is a diagram (part 4) for explaining allocation of a reservation request packet transmission slot;

FIG. 9 is a diagram (part 5) for explaining allocation of a reservation request packet transmission slot;

FIG. 10 is a diagram illustrating a change in the number of time slots for transmitting a reservation request packet.

FIG. 11 is a diagram for explaining a change in the number of spreading codes for transmitting a reservation request packet.

FIG. 12 is a diagram for explaining changes in the number of time slots and the number of spreading codes for transmitting a reservation request packet.

FIG. 13 is a diagram for explaining transmission restriction of a reservation request packet.

FIG. 14 is a diagram (part 1) for explaining assignment of a random access packet transmission slot;

FIG. 15 is a diagram (part 2) for explaining assignment of a random access packet transmission slot.

FIG. 16 is a diagram (part 3) for explaining assignment of a random access packet transmission slot.

FIG. 17 is a diagram (part 4) for explaining assignment of a random access packet transmission slot;

FIG. 18 is a diagram (No. 5) for describing allocation of random access packet transmission slots.

FIG. 19 is a diagram for explaining a change in the number of time slots for transmitting a random access packet.

FIG. 20 is a diagram for explaining a change in the number of spreading codes for random access packet transmission.

FIG. 21 is a diagram for explaining changes in the number of time slots and the number of spreading codes for random access packet transmission.

FIG. 22 is a diagram for explaining transmission restriction of a random access packet.

FIG. 23 is a diagram (part 1) for explaining allocation of a spreading code according to a transmission amount;

FIG. 24 is a diagram (part 2) for explaining allocation of a spreading code according to a transmission amount;

FIG. 25 is a diagram for explaining allocation of the number of time slots according to the amount of transmission.

FIG. 26 is a diagram (part 3) for explaining allocation of a spreading code according to a transmission amount;

FIG. 27 is a diagram (part 1) for describing allocation of a time slot and a spreading code according to a transmission amount;

FIG. 28 is a diagram (part 2) for explaining assignment of a time slot and a spreading code according to a transmission amount;

FIG. 29 is a diagram (part 3) for explaining allocation of a time slot and a spreading code according to a transmission amount;

[Explanation of symbols]

 f1 to fn Subcarrier TS Time slot TF Frame length

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Sadayuki Abeda 2-1-1, Nagatacho, Chiyoda-ku, Tokyo Sanno Park Tower 41F NTT Mobile Communications Network Co., Ltd. (72) Inventor Mamoru Sawabashi Tokyo 2-11-1, Nagatacho, Chiyoda-ku, Tokyo Sanno Park Tower 41F NTT Mobile Communications Network Co., Ltd. F-term (reference) 5K022 AA08 AA09 AA10 EE02 EE11 EE22 FF01 5K028 AA11 BB06 CC02 CC05 DD01 DD02 KK32 LL02 LL12 LL42 LL43 MM13 RR01 RR03 TT02 5K030 GA01 HA08 HB11 HB28 HC09 JL01 JT02 JT09 LA17 LA18 LB14 5K067 AA13 BB03 BB04 CC08 CC10 DD53 EE02 EE10 EE71 9A001 BB04 CC05 EE02 EE04 HH34 KK56

Claims (18)

[Claims] 1. An uplink packet transmission method in a multicarrier / DS-CDMA mobile communication system having n (n is a natural number of 2 or more) subcarriers, wherein: A frame that is a delimiter is set, and a time slot obtained by dividing the frame into F frames (F is a natural number of 2 or more) is set. An uplink packet transmission method, characterized in that the packet is spread by a spreading code according to timing and transmitted to a base station. 2. The uplink packet transmission method according to claim 1, wherein the mobile station requests the base station to allocate a time slot and a spreading code by transmitting a reservation request packet when transmitting the packet. The base station assigns a time slot and a spreading code to the requested mobile station, and the mobile station spreads and transmits a packet with the assigned spreading code in the time slot assigned by the base station. Characteristic uplink packet transmission method. 3. The uplink packet transmission method according to claim 1, wherein the mobile station performs random access to any one of the communication channels without requesting the base station to allocate a time slot. An uplink packet transmission method, comprising transmitting a packet. 4. The uplink packet transmission method according to claim 1, wherein the transmission rate of the mobile station is changed according to a transmission amount of a packet transmitted by the mobile station. Packet transmission method. 5. The uplink packet transmission method according to claim 2, wherein the base station allocates k1 (k1 is a natural number, k1 ≦ F × n) as time slots for transmitting the reservation request packet, M for spreading reservation request packet
One (m1 is a natural number, m1 ≦ the total number of usable spreading codes) is allocated, and the mobile station spreads the reservation request packet with one of the allocated spreading codes in the allocated time slot. An uplink packet transmission method, comprising: transmitting an uplink packet. 6. The uplink packet transmission method according to claim 5, wherein the base station determines the number k of time slots for transmitting the reservation request packet according to the number of reservation request packets from the mobile station in a predetermined period.
1. An uplink packet transmission method, wherein 1 is changed. 7. The uplink packet transmission method according to claim 5, wherein the base station sets a number m1 of spreading codes for transmitting the reservation request packet according to the number of reservation request packets from the mobile station in a predetermined period. A method for transmitting an uplink packet, comprising: 8. The uplink packet transmission method according to claim 5, wherein the base station determines the number k of time slots for transmitting the reservation request packet in accordance with the number of reservation request packets from the mobile station in a predetermined period.
1 and the number m of spreading codes for transmitting the reservation request packet
1. An uplink packet transmission method, wherein 1 is changed. 9. The uplink packet transmission method according to claim 5, wherein the base station notifies the mobile station of a transmission restriction of the reservation request packet when the number of reservation request packets from the mobile station in a predetermined period is large. The mobile station transmits a reservation request packet according to the restriction. 10. The uplink packet transmission method according to claim 3, wherein the base station has k2 time slots (k2 is a natural number and k2 ≦ F × n) as time slots in which the mobile station can perform packet transmission by random access. , And m2 (m2 is a natural number,
m2 ≦ the total number of usable spreading codes), wherein the mobile station spreads and transmits a packet to be randomly accessed with one of the allocated spreading codes in the allocated time slot. Uplink packet transmission method. 11. The uplink packet transmission method according to claim 10, wherein the base station determines the number of time slots for random access packet transmission according to the number of random access packets from the mobile station in a predetermined period. An uplink packet transmission method, wherein k2 is changed. 12. The uplink packet transmission method according to claim 10, wherein the base station determines the number of spreading codes for random access packet transmission according to the number of random access packets from the mobile station in a predetermined period. An uplink packet transmission method, wherein m2 is changed. 13. The uplink packet transmission method according to claim 10, wherein the base station determines the number of time slots for random access packet transmission according to the number of random access packets from the mobile station in a predetermined period. k2 and the number m2 of spreading codes for transmitting the random access packet are changed. 14. The uplink packet transmission method according to claim 10, wherein the base station restricts transmission of random access packets to the mobile station when the number of random access packets from the mobile station in a predetermined period is large. The mobile station performs a random access according to the restriction. 15. The uplink packet transmission method according to claim 4, wherein the base station has p mobile stations (where p is a natural number and p ≦ usable spreading) according to the amount of transmission of the mobile station. (A total number of codes) spreading code is allocated. 16. The uplink packet transmission method according to claim 4, wherein the base station assigns a spreading code having a different spreading factor to the mobile station according to the amount of transmission of the mobile station. Uplink packet transmission method. 17. The uplink packet transmission method according to claim 4, wherein the number of the base stations is q (q is a natural number, q ≦ F × n) according to the amount of transmission of the mobile station. Uplink packet transmission method, wherein a time slot is allocated. 18. The uplink packet transmission method according to claim 4, wherein the base station sets a spreading code number p (p is a natural number, p ≦ a usable spreading code) in accordance with a transmission amount of the mobile station. ), Spreading codes of different spreading factors, number of time slots q
An uplink packet transmission method, wherein at least two of q (q is a natural number, q ≦ F × n) are changed and assigned.