JPH10308723A - Radio communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To guarantee communication quality for each connectionless type and connection type call by managing the multiplicity number of code channels at a base station and respectively discriminating whether or not code channel assignment is permitted to connectionless type and connection type calls based on the compared result of multiplicity number and threshold value. SOLUTION: Through a connection system managing part 2, the base station discriminates whether a call originating request from a mobile terminal shows the connectionless (CL) type or the connection (CO) type. In the case of CL type, a current multiplicity number TT (sum of the code channel number of the CO type and the code channel number of the CL type) is compared with a threshold value T1 while referring to a channel table 7 and in the case of TT<T1, the request is accepted by a channel assign part 8 but in the case of TT>T1, this request is not accepted. In the case of CO type, the multiplicity number TT is compared with a threshold value T2 (T1>T2) and in the case of TT<T2, that request is accepted but in the case of TT>T2, it is not accepted. Thus, communication quality can be guaranteed for each CL or CO type call and higher communication quality can be guaranteed for the CO type.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a code division multiple access (CDMA) wireless communication system.

[0002]

2. Description of the Related Art A code division multiple access (CDMA) system is employed as one system of a mobile communication system capable of increasing user capacity and improving communication quality. In the CDMA system, a specific code is assigned to each line, and a modulated wave of the same carrier frequency is spread with this code and sent. On the receiving side, each code is synchronized to identify a desired line. The connection method is SSMA (SpreadSpectrum Multiple Access).
) Method. The CDMA system does not require an initial connection process, and has the advantage that it can be directly communicated for each call as long as the codes are determined, and that it is excellent in confidentiality and interference resistance. .

In a communication system adopting the CDMA system, a plurality of base stations having a service area within a predetermined distance range in which radio communication is possible are arranged such that the service area partially overlaps with the service area of an adjacent base station. The mobile terminal in the service area performs a communication service with the base station, and when moving to an adjacent service area, the communication service performs control operation such as baton touching the destination base station. As a result, the communication service for the mobile terminal can be continued. The service area of each base station in such a system is called a cell, and since the location registration of terminals and execution and management of communication services are performed in cell units, it is called a cellular system.

FIG. 5 is a diagram for explaining the outline of a CDMA cellular system. 10 is a cell, 11 and 12 are CDMA
The base stations 13, 14 are mobile terminals. The CDMA base stations 11 and 12 are arranged in a distributed manner, and a range in which radio waves from one base station can be reached is a service area of the base station, that is, a cell. The CDMA base stations 11 and 12 can communicate with the mobile terminals 13 and 14 in the cell 10 by performing wireless communication according to the CDMA scheme.

[0005] In general, in a CDMA cellular system, a plurality of base stations are dispersedly arranged, and the range of radio waves at each base station is defined as the service area (cell) of the base station. Uses a same carrier frequency to transmit and receive a plurality of channels by code division multiple access. Then, in order to enable continuous communication between the moving communication terminal and the base station, in a cell adjacent to a certain cell, the base station of the cell uses the moving communication terminal. Communication is performed by CDMA using the same carrier frequency as the carrier frequency.

[0006] In the CDMA cellular system, radio waves of the same carrier frequency are used in a plurality of adjacent cells, so that a signal from a mobile terminal belonging to a base station of another cell interferes with a receiver of another base station. Mix as a signal. Usually, these CDMA interference signals from outside the own cell behave similarly to noise in the receiving device of the base station because the type of code, code timing, transmission line response state, and the like are unknown.

By the way, there are two types of connection methods between the transmitting and receiving terminals for communication, a connection (CO) type and a connectionless (CL) type.

The connection (CO) type is a method that requires a procedure for confirming a sender and a receiver before starting communication and setting a communication line as shown in FIG. This method has the advantage that reliable communication is possible via the connected line and that the information transfer after connection is simple. Is not very efficient. This connection method is used for real-time communication where little delay is allowed.

On the other hand, the connectionless (CL) type, as shown in FIG. 7, does not establish a communication line in advance but collectively packetizes data to be transmitted, assigns each to a destination, and sends the packet to the network. This is a method in which the destination is confirmed and sent for each packet. In this method, short data can be efficiently transmitted because the connection does not take much time. However, it can be said that reliability is inferior to connection type.

[0010]

In a cellular system, a code division multiple access (CDM) is one of the communication systems.
A) is adopted. This is a method of performing communication by spreading the energy of the original information bits over a wide frequency band on the frequency axis.
Compared with other systems, it is superior in realizing interference resistance, realizing path diversity, and simple handoff.

[0011] The user capacity in CDMA is determined by the interference power (interference signal power) from all multiplex users. For this reason, in a CDMA system, very strict transmission power control is required for a mobile terminal in order to increase the user capacity. That is, the number of multiplexed channels in one base station is limited, and if the interference power exceeds the limit, communication becomes impossible.

In consideration of future multimedia communication, it is necessary to guarantee different communication quality depending on the type of call. When considering the communication quality in such a CDMA system, it is necessary that connection-type calls can guarantee higher quality than connection-less calls. Therefore, there is a need for a technology that can more reliably obtain such communication quality.

The present invention is intended to solve such a problem, and an object of the present invention is to improve communication quality in multimedia communication, in particular, communication quality for each call connection method (connection type, connectionless type). An object of the present invention is to provide a CDMA wireless communication system capable of guaranteeing.

[0014]

In order to achieve the above object, a radio communication system according to the present invention has a base station and a mobile terminal, wherein the base station is a mobile terminal. Means for managing the number of multiplexed code channels in a base station in a wireless communication system that allocates a code channel for communication with a mobile terminal when a call is made from a mobile terminal or when a call is received to a mobile terminal; Means for comparing the number of multiplexes with a threshold value and determining whether code channel assignment is permitted or not for a connectionless call based on the comparison result.

Further, the radio communication system according to the present invention has a base station and a mobile terminal, and the base station operates when a call from the mobile terminal or a call to the mobile terminal is received. In a wireless communication system that allocates code channels for communication with the mobile terminal, means for managing the number of multiplexed code channels in the base station, and the number of multiplexed managed code channels and a threshold are compared. Means for determining whether or not code channel assignment is permitted for a connection-type call based on the information. further,
A wireless communication system according to the present invention includes a base station and a mobile terminal, wherein the base station communicates with the mobile terminal when a call is made from the mobile terminal or when a call is received to the mobile terminal. In a wireless communication system for allocating code channels for communication, means for managing the number of multiplexed code channels in a base station, and comparing the number of multiplexed managed code channels with a plurality of thresholds, and performing connection based on the comparison result. Means for determining whether code channel allocation is permitted or not for a call of a connection type and a connection type.

More specifically, as described in claim 4, the number of multiplexed managed code channels and a first threshold and a second threshold (where first threshold> second threshold) When the number of code channel multiplexes is less than the first threshold, code channel allocation for connectionless and connection-type calls is permitted, and when the number of code channel multiplexes is less than the second threshold, connection-type calls are allowed. Only allow code channel assignment.

According to the first to fourth aspects of the present invention,
In assigning a code channel to a connection-type or connection-less type call, an appropriate limit can be added in consideration of the limit of the number of code channels to be multiplexed, and connection-type and connection-less type communication quality can be guaranteed. . Also, higher communication quality can be guaranteed for the connection type than for the connectionless type.

Further, a wireless communication system according to the present invention includes a base station and a mobile terminal,
In a wireless communication system that allocates a code channel for communication with a mobile terminal at the time of a call from a mobile terminal or an incoming call to a mobile terminal, the base station determines whether the type of call is a connection type, which is a connectionless type. Means for identifying;
Means for assigning a code channel of a different carrier frequency to the call according to the type of the identified call.

In the present invention, by using code channels of different carrier frequencies for connectionless communication and connection-type communication, a certain quality can be guaranteed for each connection method, and connection-type communication can be performed more than connectionless-type communication. By assigning more carrier frequencies to the connection type, higher communication quality can be guaranteed for the connection type than for the connectionless type.

Further, the radio communication system according to the present invention has a base station and a mobile terminal, and the base station transmits a call from the mobile terminal or receives a call from the mobile terminal. In a wireless communication system that allocates a code channel for communication with the mobile terminal, a means for identifying whether the type of call is a connection type, which is a connectionless type, and a connectionless type in advance according to the identified call type. Means for selecting a code channel to be allocated to a call from code channels grouped into a type and a connection type.

In the present invention, by grouping code channels used in connectionless communication and connection-type communication, a certain quality can be guaranteed for each connection method, and connection-type communication is more reliable than connectionless-type communication. By allowing more code channels to be allocated to the connection type, higher communication quality can be guaranteed for the connection type than for the connectionless type.

Further, according to the present invention, in the wireless communication system according to any one of claims 1 to 4, means for measuring an interference wave power from a surrounding base station in the base station. And means for setting the threshold value based on the measurement result of the interference wave power, so that the communication quality can be further improved.

Further, according to the present invention, as set forth in claim 8, in the wireless communication system according to any one of claims 1 to 4, the mobile terminal is communicating with each of the connectionless connection type and the connection type connection method. When handing off to
By assigning code channels with priority given to connection-type calls, connection-type communication quality can be further improved.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

A connectionless type (hereinafter abbreviated as a CL type) and a connection type (hereinafter abbreviated as C) between a base station and a mobile terminal in the CDMA communication system of the present embodiment.
Abbreviated as O type. ) Can be used for communication. However, it is also possible to simultaneously communicate with the CL type and the CO type using a plurality of channels.

FIG. 1 shows the configuration of the base station. As shown in FIG. 1, the base station includes an antenna 1, a transmission / reception unit 2, a channel processing unit 3, a network interface unit 4, an interference wave power measurement unit 5, and a control unit 6. Also,
As shown in FIG. 2, the channel processing unit 3 includes a channel management table 7, a channel allocation unit 8, and a connection mode management unit 9
Is provided.

Hereinafter, embodiments of the present invention will be described in detail.

(Embodiments according to claims 1 to 4) The base station always manages the connection method (CL type, CO type) and the multiplex number of the code channel with which the base station is currently communicating. .

FIG. 3 shows an example of the channel management table 7 when a plurality of carrier frequencies are used in the base station.
However, in this embodiment, the carrier frequency is one (F1).
It will be described on the assumption that Further, the total number of communication code channels usable in one base station is represented by MC (carrier frequency F1).
), And certain values T1 and T2 (<MC) are set as threshold values for the CL type and the CO type, respectively. However, the CO-type connection method needs to guarantee higher communication quality than the CL-type connection method, so that T1> T2.

Further, assuming that the number of code channels communicating in the CO type at a certain base station is TO1 and the number of code channels communicating in the CL type is TL1, the current multiplexing number TT in the base station is TT = TO1 + TL1. However, it is assumed that TO1 = TL1 = 0 in the initial state.

When a mobile terminal originates a call, the mobile terminal first selects the CL type or the CO type depending on the type of call.
However, at this time, a plurality of channels (CL type and CO type) may be requested at the same time. For example, when connecting to the Internet for e-mail transmission or the like, select the CL type, and when performing real-time communication where delay is not allowed, select the CO type.

When the mobile terminal issues a call request to the base station, as shown in FIG. 4, the connection method management unit 9 of the channel processing unit 3 transmits the call request to a CL type request. Or a CO type request (step A). Then, when determining that the mobile terminal requests the base station for the CL type, the channel processing unit 3 of the base station refers to the channel management table 7 and compares the current multiplex number TT with the threshold T1 ( Step B) If TT <T1 (Step C), the channel assignment unit 8 accepts a request from the mobile terminal and assigns a code channel (Step D). Conversely, if TT> = T1, the base station does not allocate a code channel and assumes a call loss (step E).

On the other hand, when the mobile terminal requests the CO type from the base station, the channel processing unit 3 of the base station similarly refers to the channel management table 7 and sets the current multiplexing number TT and the threshold T2 (where T1 > T2) (step F), and if TT <T2 (step G), secure a connection between the transmitting terminal and the receiving terminal (step H).
If the connection can be secured, a request from the mobile terminal is accepted and a code channel is allocated (step I). On the other hand, if TT> = T2, the base station does not allocate a code channel to the mobile terminal and assumes a call loss (step E).

Similarly, in the case of an incoming call to a mobile terminal, in the channel processing unit 3 of the base station, the current multiplexing number and the threshold T
1, after comparing with T2, a code channel is allocated as in the case of calling.

When a mobile terminal moves to a cell managed by another base station and performs handoff, channel assignment in the destination base station is performed in the same manner as when a mobile terminal originates a call.

As described above, in the present embodiment, separate thresholds T1 and T1 are set for CL-type and CO-type calls and incoming calls.
2 (where T1> T2), and if the current multiplexing number TT of the code channel is equal to or less than the threshold value T1, it is permitted to allocate the code channel to any of the CO-type and CL-type calls, Current code channel multiplexing number T
If T is equal to or less than the threshold value T2, it is permitted to allocate a code channel only to CO-type calls.
In assigning a code channel to each type of call, an appropriate limit can be added in consideration of the limit of the number of code channels to be multiplexed, and communication quality of the CO type and the CL type can be guaranteed. Also, higher communication quality can be guaranteed for the CO type than for the CL type.

(Embodiments according to claims 5 and 6) One base station has a plurality of carrier frequencies (carrier frequencies) F1, F
2 can be used. Then, the base station allocates a code channel of the carrier frequency F1 to the CL type request, and allocates a code channel of the carrier frequency F2 to the CO type request.

When a mobile terminal originates a call, first, a CL type or a CO type is selected depending on the type of call. However,
A plurality of channels (CO type and CL type) may be requested at the same time. For example, when connecting to the Internet for e-mail transmission or the like, select the CL type, and when performing real-time communication where delay is not allowed, select the CO type.

In response to a call request from a mobile terminal, the base station determines whether the call request is a CL-type or a CO-type request by the connection method management unit 9 of the channel processing unit 3. When the mobile terminal determines that the base station requests the CL type, the channel allocating unit 8 of the base station checks whether or not the code channel of the carrier frequency F1 can be allocated. For example, a code channel is allocated to the mobile terminal. If allocation is not possible, a call loss is made without allocating a code channel to the mobile terminal.

On the other hand, when the mobile terminal requests the CO type from the base station, the channel allocating unit 8 of the base station checks whether or not the code channel of the carrier frequency F2 can be allocated. Secure the connection between the terminal and the receiving terminal. If the connection can be secured, a request from the mobile terminal is accepted and a code channel is allocated to the mobile terminal. Conversely, if a code channel cannot be allocated to the mobile terminal due to reasons such as a lack of a connection or a lack of channels, a call loss is made without allocating a code channel to the mobile terminal.

Further, three or more types of carrier frequencies (carrier frequencies) usable in one base station, that is, F1 and F
When there are carrier frequencies of 2,..., Fn, the carrier frequencies to be allocated to the CL-type communication are changed from F1 to Fm.
, And the carrier frequency assigned to the CO-type communication is from F (m + 1) to Fn (where m <n).
Thus, each carrier frequency may be divided into two groups in advance, and each carrier frequency group may be used for CO-type communication and CL-type communication.

Instead of dividing the channel for CO-type communication and the channel for CL-type communication by the carrier frequency, code channels usable per carrier frequency are divided into two groups in advance. May be assigned to CL-type communication and the other code channel group may be assigned to CO-type communication.

For example, when the total number of communication code channels usable in one carrier frequency is CC, the X code channel is used for CL type communication and the remaining (CC-X) channel is used for CO type communication. use.

As described above, according to the present embodiment, the CL type communication and the CO type communication use different carrier frequency code channels, or the CL type communication and the C type
By grouping the code channels used in the O-type communication, for example, a certain quality can be guaranteed for each of the CL-type communication and the CO-type communication, and more carriers are provided in the CO-type communication than in the CL-type communication. By assigning frequencies and code channels, it is possible to guarantee higher communication quality for the CO type than for the CL type.

(Embodiment of Claim 7) The interference wave power measuring section 5 of the base station can measure the interference wave power from its own base station and the surrounding base stations. The base station manages the number of code channels (the number of available multiplexes) communicable with the base station determined by the measurement result of the interference wave power in the channel management table 7 shown in FIG. That is, the number of available multiplexes in the base station changes depending on the surrounding conditions.

Therefore, in the present embodiment, the thresholds T1 and T2 for the CL type and the CO type shown in the first embodiment are varied according to the multiplexable number of communication.

For example, the number of multiplexes that can be communicated at a given time is
When P is set, T1 = TP / 2 and T2 = TP. Then, for channel requests from mobile terminals after this point, code channels are allocated according to these thresholds T1 and T2 in the same manner as in the above embodiment.

As described above, in the present embodiment, the communication quality can be further improved by changing the threshold value according to the number of multiplexes that can be communicated at the base station determined by the measurement result of the interference wave power.

(Embodiment 8) In FIG. 5, when a mobile terminal 13 communicating with a base station 11 moves and enters a cell managed by another base station 12, a handoff is performed. The mobile terminal 13 has a plurality of connection methods (CL type, C type).
In the case of communication in the (O-type), the base station 12 requests the access base station 12 for code channels of a plurality of connection methods. Then, the base station 12 sends the request from the mobile terminal 13 to the channel processing unit 3
Is determined by the connection method management unit 9.

At this time, the destination base station 12 refers to the channel management table 7 of the channel processing unit 3 to determine whether or not the request from the mobile terminal 12 can be satisfied. The channel allocation unit 8 allocates a code channel to the mobile terminal 12. When all the requests from the mobile terminals 12 cannot be satisfied, the channel assignment unit 8 assigns a code channel by giving priority to a CO-type call.

It is to be noted that the present invention is not limited to a code division multiple access system, but by replacing a code channel with a slot, a time division multiple access (TDMA) is provided.
The method is also applicable.

[0052]

As described above, according to the radio communication system of the present invention, when assigning a code channel to a connection-type or connection-less type call, an appropriate restriction considering the limit of the number of multiplexed code channels is imposed. It is possible to guarantee connection-type and connectionless-type communication quality. Also, higher communication quality can be guaranteed for the connection type than for the connectionless type.

Further, according to the present invention, a fixed quality can be guaranteed for each connection method by using code channels of different carrier frequencies for connectionless communication and connection-type communication. By assigning more carrier frequencies to the connection type, it is possible to guarantee higher communication quality to the connection type than to the connectionless type.

Further, according to the present invention, by classifying code channels used in connectionless communication and connection-type communication into groups, a certain quality can be guaranteed for each connection method, and the present invention is more effective than connectionless communication. By allowing more code channels to be allocated to the connection type, it is possible to guarantee higher communication quality to the connection type than to the connectionless type.

Further, according to the present invention, the threshold value is dynamically set based on the measurement result of the interference wave power, so that the communication quality can be further improved.

Further, according to the present invention, when the mobile terminal is handed off during communication by the connectionless connection type and the connection type connection method, the connection type call is preferentially assigned and the code channel is assigned, whereby the connection is established. The communication quality of the model can be further improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a base station in a CDMA system according to the present invention.

FIG. 2 is a diagram illustrating a configuration of a channel processing unit in the base station of FIG. 1;

FIG. 3 is a diagram showing a configuration of a channel management table in the base station of FIG. 1;

FIG. 4 is a flowchart showing a processing procedure of code channel allocation for each request of CL type and CO type in the base station of FIG. 1;

FIG. 5 is a diagram for explaining a conventional CDMA system.

FIG. 6 is a diagram for explaining connection-oriented communication.

FIG. 7 is a diagram for explaining connectionless communication.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Antenna 2 ... Transmission / reception part 3 ... Channel processing part 4 ... Network interface 5 ... Interference wave power measurement part 6 ... Control part 7 ... Channel management table 8 ... Channel assignment part 9 ... Connection method Management unit 10: Cell 11, 12: Base station 13, 14: Mobile terminal

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masahiro Iguchi 1 Tokoba, Komukai Toshiba-cho, Saisaki-ku, Kawasaki-shi, Kanagawa Inside the Toshiba R & D Center

Claims (8)

[Claims] 1. A wireless communication system having a base station and a mobile terminal, wherein the base station allocates a code channel for communication with the mobile terminal when calling from the mobile terminal or when receiving a call to the mobile terminal. A means for managing the number of multiplexed code channels in the base station; and comparing the managed number of multiplexed code channels with a threshold value, and determining whether to permit the code channel allocation for a connectionless call based on the comparison result. Wireless communication system comprising: 2. A wireless communication system having a base station and a mobile terminal, wherein the base station allocates a code channel for communication with the mobile terminal when calling from the mobile terminal or when receiving a call to the mobile terminal. A means for managing the number of multiplexed code channels in the base station, and comparing the managed number of multiplexed code channels with a threshold value, and determining whether or not to permit the code channel allocation for a connection-type call based on the comparison result. A wireless communication system comprising: a determination unit. 3. A wireless communication system having a base station and a mobile terminal, wherein the base station allocates a code channel for communication with the mobile terminal when calling from the mobile terminal or when receiving a call to the mobile terminal. In the means for managing the number of multiplexed code channels in the base station, comparing the number of multiplexed managed code channels and a plurality of thresholds, based on the comparison result, for the connectionless and connection type call Means for determining whether code channel assignment is permitted or not, respectively. 4. A radio communication system comprising a base station and a mobile terminal, wherein the base station allocates a code channel for communication with the mobile terminal when calling from the mobile terminal or when receiving a call to the mobile terminal. And means for managing the number of multiplexed code channels in the base station, and the number of multiplexed code channels and the first and second thresholds (where first threshold> second threshold). In comparison, when the number of code channel multiplexes is less than the first threshold, the code channel assignment for connectionless and connection-type calls is permitted, and when the number of code channel multiplexes is less than the second threshold, connection-type calls are allowed. Means for permitting the code channel allocation only for the wireless communication system. 5. A wireless communication system having a base station and a mobile terminal, wherein the base station allocates a code channel for communication with the mobile terminal when a call is made from the mobile terminal or when a call is received to the mobile terminal. A means for identifying whether the type of the call is a connection type that is a connectionless type, and a means for assigning a code channel of a different carrier frequency to the call according to the type of the identified call. A wireless communication system, comprising: 6. A wireless communication system having a base station and a mobile terminal, wherein the base station allocates a code channel for communication with the mobile terminal when calling from the mobile terminal or when receiving a call to the mobile terminal. In, means for identifying whether the type of the call is a connection type that is a connectionless type, and, according to the identified type of the call, codes previously grouped into a connectionless type and a connection type Means for selecting a code channel to be assigned to the call from among the channels. 7. The wireless communication system according to claim 1, wherein the base station measures interference wave power from surrounding base stations, and the threshold value is determined based on the measurement result of the interference wave power. A wireless communication system, further comprising: 8. The wireless communication system according to claim 1, wherein when the mobile terminal is handed off during communication in each of the connectionless connection type and the connection type connection method, the connection type call is prioritized. A wireless communication system, further comprising means for allocating a code channel.