KR20000052159A - Method for specifying slot-cycle-index in cellular system - Google Patents

Abstract

PURPOSE: A method for setting up a slot-cycle-index in a cellular system is provided to improve speech quality by reducing a delay time of incoming call and to accurately select a base station which a mobile station synchronizes when idle handoff is generated so much, by reducing a paging channel monitoring time through setting up a value of the slot-cycle-index as zero. CONSTITUTION: A method for setting up a slot-cycle-index in a cellular system, using a code division multiple access(CDMA), comprises the steps of: setting up a slot-cycle-index of a paging channel as a zero; making a mobile station monitor a paging channel slot allocated to the mobile station itself, according to a period determined by the slot-cycle-index; and making the mobile station decide whether idle handoff is generated by the determined period.

Description

How to set slot cycle index in cellular system {METHOD FOR SPECIFYING SLOT-CYCLE-INDEX IN CELLULAR SYSTEM}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to cellular radio communication using Code Division Multiple Access (CDMA) technology. In particular, the present invention relates to a mobile terminal in a micro-cell environment or a multi-path environment. The present invention relates to a slot cycle index setting method of a cellular system that sets an appropriate slot cycle index value in consideration of a battery life of a mobile station and a quality of a cellular network.

The cellular mobile communication system divides the entire service area into a plurality of base station areas to form cells, which are small service areas, and centrally controls these base stations with a mobile switching center (MSC). This allows the subscriber to continue the call while moving from cell to cell.

FIG. 1 shows a schematic diagram of a typical cellular mobile communication network, which can be applied to all kinds of wireless systems using Code Division Multiple Access (CDMA) technology. A base station (BS) 20, 30, 40 providing a mobile communication service to a subscriber through a mobile telephone (MT) 10, and the base station is provided with a public switched telephone network. PSTN) 60 or Mobile Switching Center (MSC) 50 for connecting to other base stations.

A mobile terminal in a specific cell establishes a radio channel with a base station serving the cell and performs communication. In this case, a channel formed in the direction of the mobile station from the base station is called a forward channel, and a channel formed in the direction of the base station from the mobile terminal is called a reverse channel.

The forward channel includes a pilot channel, a synchronous channel, a paging channel, and a forward traffic channel, and the reverse channel includes an access channel and a reverse traffic channel. Traffic Channel).

In a network using code division multiple access (CDMA) technology that satisfies the standards of IS-95 and J-STD-008, when a user turns on the mobile terminal, the mobile terminal is in a Mobile Station Initialization Station. Then, the base station to be tuned is selected and acquired. Since each base station transmits a unique pilot signal, the mobile terminal selects and tunes a best pilot that transmits the strongest pilot signal.

After selecting a base station to tune, the mobile terminal tunes to the frequency and phase of the base station, and then monitors the paging channel in a mobile station idle state. An idle mobile terminal may receive a message, receive a terminating call, make an originated call, initiate location registration, or initiate message transmission through a paging channel.

The paging channel is divided into 80ms slots called paging channel slots. The mobile terminal monitors each slot of the paging channel. The base station carries a message for a mobile terminal in a specific slot, and the mobile terminal selects a slot assigned to the mobile terminal and receives a valid message in the slot.

One slot cycle in the paging channel includes 16 x T slots, where T is the length of the slot cycle. The length of slot cycle T Is given by Is a slot-cycle-index.

Since the conventional cellular network according to the prior art uses a macro cell having a relatively large cell size, the slot cycle index is set to two. If the slot cycle index is set to 2, the mobile terminal monitors one slot cycle for 5.12 seconds. That is, the mobile terminal monitors a slot allocated to itself every 5.12 seconds.

When an idle mobile terminal moves from an area of one base station to an area of another base station, an idle handoff occurs. The mobile terminal according to the related art uses an idle handoff every 5.12 seconds according to a slot cycle index. Determine whether or not. In the case of the macro cell, since the cell size is relatively large, idle handoff does not occur frequently, so even if the mobile terminal monitors the slot cycle for 5.12 seconds, there is no problem in performing the idle handoff.

However, in an environment in which many radio paths are generated due to hilly terrain or high buildings and path loss is large, a signal received by the mobile terminal may change significantly. In this case, if the mobile terminal monitors the slot cycle every 5.12 seconds, the sleep time for which the mobile terminal does not operate becomes long, and as a result, accuracy in determining idle handoff may be reduced.

In addition, as the number of mobile subscribers increased and the technology developed, the operators of the network became more granular in order to accommodate more subscribers. In a micro-cell environment in which one cell has a size of 200 to 300 m or less, an idle handoff occurs frequently because the mobile terminal may go through many cells while monitoring one slot cycle. Can be.

However, when the waiting time of the mobile terminal becomes longer in a small cell radius, the best pilot pilot signal of the maximum intensity suddenly changes, and a handoff may occur even before a comparison target for idle handoff is found.

In this case, the mobile terminal must transition from an idle state to an initialization state, and then repeat a procedure of selecting and acquiring a base station to be tuned. This process causes a lot of shaking of the antenna bar on the display screen of the terminal and causes a problem of distrust to the user.

In addition, when the slot cycle index is large in an environment where the signal strength of the mobile terminal changes significantly, the period in which the mobile terminal monitors the paging channel does not follow the period in which the signal strength changes, thus accurately displaying the paging message. There was a problem that could not be received.

Accordingly, an object of the present invention, which is designed to solve the problems of the prior art operating as described above, is to reduce the slot cycle index in a radio environment in which idle handoff may occur frequently in the mobile terminal idle state. It is to provide a slot cycle index setting method in a cellular system, which reduces the paging channel monitoring time of the.

1 is a block diagram of a typical cellular mobile communication network.

2 is a flowchart illustrating a slot cycle index setting method according to the present invention;

3 is a call processing state diagram of a mobile terminal applied to the present invention.

4 is an operation configuration diagram of a mobile terminal applied to the present invention.

<Explanation of symbols for the main parts of the drawings>

10: mobile terminal 20, 30, 40: base station

50: mobile switching center 60: public switched telephone network

An embodiment of a slot cycle index setting method in a cellular system according to the present invention, which is invented to achieve the above object, in a cellular network using a code division multiple access technique,

Setting a slot cycle index of a paging channel to zero;

Periodically monitoring a slot of a paging channel allocated to the mobile terminal by a period determined by the slot cycle index; And

And periodically determining, by the mobile terminal, whether an idle handoff is performed by a period determined by the slot cycle index.

The present invention reduces the paging channel monitoring time of the mobile terminal by setting the slot cycle index value to 0 in a micro cell environment where a cell size is relatively small or in an environment where multiple propagation paths are generated.

The mobile terminal confirms that a value of a configuration parameter previously stored is commonly used. Configuration parameters are received from configuration messages such as system parameter messages, neighbor list messages and CDMA channel list messages.

Hereinafter, with reference to the accompanying drawings will be described in detail the operating principle of the preferred embodiment of the present invention.

2 is a flowchart illustrating a slot cycle index setting method according to an embodiment of the present invention, and as shown therein, setting a slot cycle index of a paging channel to 0 (s110); Monitoring a slot of a paging channel allocated to the mobile terminal by a period determined by the slot cycle index (s120); And determining, by the mobile terminal, whether an idle handoff is performed by the period determined by the slot cycle index (s130).

In step S110, the slot cycle index for determining a period for the mobile terminal to monitor the slot of the paging channel transmitted from the base station may be set in the mobile terminal by the operator, or may be set by the base station.

To set in the mobile terminal, the operator internally sets the slot cycle index of the mobile terminal to zero. Alternatively, the base station transmits a slot cycle index set to 0 in a system parameter change message transmitted to the mobile terminal through the paging channel. According to the specification, a mobile terminal compares an internally set slot cycle index with a slot cycle index received from a base station and operates by a small value.

The mobile terminal operating by the slot cycle index set to 0 monitors the slot allocated to itself every 1.28 seconds in step s120 to find a valid paging message, and checks whether the idle handoff is performed every 1.28 seconds in step s130. To judge.

Figure 3 is applicable to all types of Personal Communication Service (PCS) system that satisfies the standard by J-STD-008, and shows a call processing state diagram of a mobile terminal applied to the present invention, As shown, when the power is turned on (110), the mobile terminal enters the initialization state (120).

Upon obtaining system timing in the initialization state 120, the mobile terminal enters an idle state 130. To receive a paging channel message, originate a call, or perform location registration in the idle state 130, the mobile terminal enters a system access state 140. The mobile terminal enters the traffic state 150 from the system access state 140 to perform a call.

The mobile terminal in the initialized state finds a base station to tune in the System Determination Substate 122. When the base station to tune in the system decision state 122 is selected, the mobile terminal enters a Pilot Channel Acquisition Substate 124.

Upon acquiring the pilot channel in the pilot channel acquisition state 124, the mobile terminal tunes to the frequency and phase of the pilot signal and then enters a synchronous channel acquisition state 126. Upon receiving a sync channel message in sync channel acquisition state 126, the mobile terminal receives system timing information, then enters Timing Change Substate 128, and then tunes to the system timing.

In the case of a mobile terminal processing a call through the state transition as described above, the mobile terminal in the idle state 130 operates in a slotted mode or a nonslotted mode.

A mobile terminal operating in nonslot mode may receive a call control message in any paging channel slot. Therefore, the mobile terminal must monitor all slots.

A mobile terminal operating in slot mode monitors the paging channel only during any assigned slot. During slots in which the paging channel is not monitored, the mobile terminal may abort or reduce processing to reduce power consumption. In general, a mobile terminal operating in slot mode monitors a paging channel for one or two slots within a slot cycle. The mobile terminal can define a slot period to preempt itself using the slot cycle index field.

The length of the slot cycle, T ego, Since is the selected slot cycle index, if the value of the slot cycle index is set to 2, T is 4 and one slot cycle consists of 16 x 4 = 64 slots. The minimum length slot cycle (slot cycle index = 0) includes 16 slots of 80 ms each, so the length is 1.28 seconds and the maximum length slot cycle includes 2048 slots.

For example, if the mobile terminal starts monitoring the paging channel at slot 8, the next slot to start monitoring the channel is slot 72 after one cycle (64 slots).

Table 1 shows the relationship between the slot cycle index and the slot cycle time for receiving the paging message.

Slot cycle index Slot cycle time 0 1.28 sec One 2.56 seconds 2 5.12 seconds 3 10.24 seconds

4 illustrates an operation configuration diagram of a mobile terminal according to the present invention. As shown in FIG. 4, a slot mode mobile terminal wakes up 200 ms (or 360 ms) before a specific assigned slot. (Wake-up) to monitor for idle handoff and to monitor the strength of the strongest pilot signal. When this 200 ms (or 360 ms) time has elapsed, the mobile terminal monitors the paging channel for the slot period (80 ms) allocated to it to check whether there is a message received from the paging channel. If there is a message received from the paging channel, the message is analyzed and if no message is received it waits until the next wake-up time.

The mobile terminal operates in the sleep mode for the remaining time except for the 200 ms (or 360 ms) time and the slot time (80 ms). In the standby mode, since hardware devices (eg, a processor, a demodulator, etc.) of the mobile terminal do not operate, the mobile terminal in the standby mode does not perform an idle handoff.

Since idle handoff occurs frequently in a micro cell environment or a multi propagation path environment, the mobile terminal needs to frequently monitor whether there is an idle handoff. Therefore, if the slot cycle index is set to 0, the mobile terminal monitors the idle handoff every 1.28 seconds, and as a result, the waiting time of the mobile terminal is reduced.

In addition, since the mobile terminal monitors the slot allocated to the mobile station every 1.28 seconds, when the base station requests the incoming call to the mobile terminal through the paging channel, the mobile terminal can quickly answer the incoming call. Therefore, it is possible to increase the probability of call reception and to reduce the time required for call reception.

If the waiting time is prolonged in a small cell environment, the strength of the pilot signals may vary greatly during the waiting time. When the strength of the pilot signal changes, the mobile terminal must transition from the idle state 130 to the initialization state 120 to select and acquire the base station to tune through the various states 122-128 again. Therefore, to reduce this procedure as much as possible, set the value of the slot cycle index to zero.

In the present invention operating as described in detail above, the effects obtained by the representative ones of the disclosed inventions will be briefly described as follows.

The present invention can reduce the paging channel monitoring time of the mobile terminal by setting the slot cycle index value to 0, thereby accurately selecting a base station to which the mobile terminal will tune in an environment in which frequent idle handoffs occur, and delaying call reception. There is an effect that can reduce the time to improve the quality of the call.

Therefore, the present invention can improve the accuracy of receiving a paging message and improve the user's confidence in a mobile communication service in a dense urban environment or a micro cell environment.

Claims (10)

In a cellular network using code division multiple access technology, Setting a slot cycle index of a paging channel to zero; Periodically monitoring, by the mobile terminal, a paging channel slot allocated to the mobile station according to the period determined by the slot cycle index; And And periodically determining, by the mobile terminal, whether an idle handoff is performed by a period determined by the slot cycle index. The slot cycle index setting method of the cellular system. The method of claim 1, wherein the setting of the slot cycle index comprises: A method of setting a slot cycle index in a cellular system, wherein the operator sets the slot cycle index of the mobile terminal to zero. The method of claim 1, wherein the setting of the slot cycle index comprises: And a base station transmits a system parameter change message including a slot cycle index set to 0 to a mobile terminal. The method of claim 1, wherein the period determined by the slot cycle index, How to set slot cycle index in cellular system, which is 1.28 seconds. In a cellular network using code division multiple access technology, Setting a slot cycle index for monitoring a paging channel to zero; Determining, by the slot cycle index, whether the mobile terminal is idle handoff every 1.28 seconds. 6. The method of claim 5, wherein the cellular network is applied to a micro cell environment. 6. The method of claim 5, wherein the cellular network is applied to a dense urban environment. In a cellular network using code division multiple access technology, Setting a slot cycle index of a paging channel to zero; Monitoring, by the slot cycle index, a slot of a paging channel allocated to the mobile terminal every 1.28 seconds by the slot cycle index. 10. The method of claim 8, wherein the cellular network is applied to a micro cell environment. 9. The method of claim 8, wherein the cellular network is applied to a dense urban environment.