Dedicated channel assignment method for packet transmission

[0001] The present invention relates to data transmission between a mobile station MS (mobile station) and a base station BS (base station) in a CDMA (code division multiple access) mobile communication system, in particular. The present invention relates to a dedicated channel allocation method for packet transmission in a control unit of a CDMA medium access control MAC (media access control) layer when transmitting packet data between a mobile station and a base station in a CDMA mobile communication system.

PROBLEM TO BE SOLVED: In a conventional wireless data service, a data traffic service is provided in the same manner as a voice traffic service based on a circuit switching method. Using this method has the advantage of a short delay time. However, in the data service as well, unlike the voice service, since the channel is occupied for a long time for the data call, there is a problem that the radio resource efficiency becomes very low and the degree of packet change becomes very small. It was. In particular, in the CDMA mobile communication system, in order to maintain the channel, there is a problem that unnecessary power is consumed and the quality of the entire system is deteriorated.

[0003] [Problems to be Solved by the Invention] In order to solve the problems of the above-mentioned conventional techniques, the present invention wirelessly transmits packet data between a mobile station and a base station in a CDMA mobile communication system. It is an object of the present invention to provide a dedicated channel allocation method for packet transmission in a control unit of a CDMA MAC layer, which can improve resource efficiency.

[Means for Solving the Problems] In order to achieve the above object, the present invention relates to packet transmission between a mobile station and a base station in a CDMA mobile communication system including a mobile station and a base station. In the dedicated channel allocation method for the above, the first step of determining the service option of the packet according to the occurrence of the packet in the control unit of the MAC layer of the mobile station, and whether the service option of the packet is connection type communication. For example, a second step of requesting a designated control channel DCCH (dedicated control channel) allocation and receiving the DCCH, a third step of requesting a designated traffic channel DTCH (dedicated traffic channel) allocation and receiving the DTCH, and the DTCH It is characterized by including a fourth step of transmitting the packet via.

[0005] Here, it is desirable that the control unit of the MAC layer of the mobile station transitions to the stopped state before determining the service option of the packet.

[0006] Further, the control unit of the MAC layer of the mobile station may request the control unit of the MAC layer of the base station to allocate the DCCH.

[0007] The third step includes a fifth step in which the control unit of the MAC layer of the mobile station transitions to the control holding state when the timer in the stopped state does not end before receiving the DCCH, and the base station. It is desirable that the control unit of the MAC hierarchy of the above includes the sixth step of requesting the DTCH allocation.

[0008] Further, in the fourth step, when the timer in the control holding state does not end before receiving the DTCH, the control unit of the MAC layer of the mobile station is activated before transmitting the packet via the DTCH. The 7th step of transitioning to the state, the 8th step of transmitting the packet before the timer of the active state ends, and the control unit of the MAC layer of the mobile station after the timer of the active state ends. It is desirable to include the ninth step of transitioning to the holding state.

[0009] In the second step, when the service option of the packet is connectionless communication, the packet is transmitted via the arbitrarily connected common traffic channel CTCH (common traffic channel). It is recommended to include 10 more steps.

[0010] Further, in the third step, when the timer in the stopped state ends before the DCCH is assigned, the control unit of the MAC layer of the mobile station transitions to the hibernation state or returns to the stopped state. It is desirable to include the 11th step further.

[0011] λ_DIndicates the required rate of the DCCH, T_SIndicates the timer value in the stopped state, and the probability of transitioning to the hibernated state is (1-λ)._D) / T_SAnd the probability of returning to the stopped state is (1-λ)._D) (1- (1 / T_S)).

[0012] In the fourth step, when the timer in the control holding state ends before the DTCH is assigned, the control unit in the MAC layer of the mobile station transitions to the stopped state or the control holding. It is desirable to include a twelfth step to return to the state.

[0013] The μ_DIndicates the required rate of the DTCH, and T_cIndicates the timer value of the control holding state, and the probability of transition to the stopped state is (1-μ)._D) / T_cAnd the probability of returning to the control holding state is (1-μ)._D) (1- (1 / T_c)).

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for allocating a dedicated channel for packet transmission according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0015] FIG. 1 is a conceptual diagram showing a stacked structure of lower CDMA protocol layers between a mobile station and a base station in the dedicated channel allocation method for packet transmission according to the embodiment of the present invention.

[0016] The protocol elements of the physical hierarchy between the mobile station and the base station control the CDMA radio interface between the mobile station and the base station. In addition, the protocol element of the MAC hierarchy controls media access, and the protocol element of the link access control LAC (Link Access Control) hierarchy controls link access. The protocol elements of the physical layer, MAC layer, and LAC layer are included in each of the mobile station and the base station.

[0017] FIG. 2 is a flowchart showing an operation between each layer control unit that performs a corresponding function of each protocol element in each layer shown in FIG. Here, the physical hierarchy control unit is a device for performing the physical hierarchy function, the MAC hierarchy control unit is a device for performing the MAC hierarchy function, and the LAC hierarchy control unit performs the LAC hierarchy function. It is a device for.

FIG. 3 is a flowchart showing a dedicated channel allocation method for packet transmission according to the embodiment of the present invention.

[0019] The first step is a step in which the control unit of the MAC layer of the mobile station determines the service option of the packet according to the generation of the packet. At this time, it is desirable to provide step S11 for transitioning the control unit of the MAC layer of the mobile station to the stopped state before step S12 for determining the service option of the packet. At this time, steps S11 and S12 correspond to the first step.

[0020] As the second step, there are the following two steps based on the result of the above determination. On the other hand, when the service option of the packet is connection type communication, the stage is to request the allocation of the designated control channel DCCH (dedicated control channel) and receive the DCCH, and steps S13 and S14 correspond to this.

[0021] In step S13, the allocation of the DCCH is requested. For example, the control unit of the MAC layer of the mobile station requests the control unit of the MAC layer of the base station to allocate the DCCH. Then, in step S14, before receiving the DCCH, it is determined whether or not the stopped timer ends, and the process proceeds to the third step.

[0022] On the other hand, when the service option of the packet is connectionless communication, the second step is a step further including the tenth step.

[0023] The tenth step is a step in which the control unit of the MAC layer of the mobile station transmits a packet via a common traffic channel (CTCH) arbitrarily connected to the control unit, and step S21 is a step to this. Applicable. As shown in the figure, the process returns to step S11 after the packet transmission.

[0024] As the third step, there are the following two steps based on the result of the above determination. One is when the stopped timer does not end before receiving the DCCH, and at this time, the third step is a step of requesting the designated traffic channel DTCH (dedicated traffic channel) allocation and receiving the DTCH. At this time, it is desirable that the third step includes the fifth step and the sixth step.

[0025] The fifth step is a step in which the control unit of the MAC layer of the mobile station transitions to the control holding state, and step S15 corresponds to this. The sixth step is a step of requesting the DTCH allocation from the control unit of the MAC layer of the base station, and step S16 corresponds to this.

[0026] In step S17, it is determined whether or not the timer in the control holding state ends before receiving the DTCH. As a result, steps S15, S16 and S17 correspond to the third step. If the timer in the control holding state does not end, the control unit in the MAC layer of the mobile station shifts to the fourth step of transitioning to the active state, and when it finishes, the process returns to step S11.

[0027] The other is when the stopped timer ends before the DCCH is assigned, at which time the third step further includes the eleventh step.

[0028] The eleventh step is a step in which the control unit of the MAC layer of the mobile station transitions to the hibernation state or returns to the hibernation state. As shown in the figure, the process proceeds from step S14 to step S21, and returns from step S21 to step S11.

[0029] As the fourth step, there are the following two steps based on the result of the determination. One is a stage in which the packet is transmitted via the DTCH when the timer in the control holding state does not end before the DTCH is assigned. At this time, it is desirable that the fourth step includes the seventh step, the eighth step, and the ninth step.

[0030] The seventh step is a step of transitioning the control unit of the MAC layer of the mobile station to the active state before transmitting the packet via the DTCH, and step S18 corresponds to this. The eighth step is a step of transmitting the packet before the timer in the active state ends, and step S19 corresponds to this.

[0031] In step S19, the control unit of the MAC layer of the mobile station transmits the packet via the assigned DTCH. Then, in step S20, it is determined whether or not the timer in the active state ends before the packet is transmitted. If it is determined that the packet is not terminated, the procedure for transmitting the packet is completed, and if it is determined that the packet is terminated, the process proceeds to the ninth step.

[0032] The ninth step is a step in which the control unit of the MAC layer of the mobile station transitions to the control holding state after the timer in the active state ends. As shown, the process returns from step S20 to step S15. As a result, the fourth step corresponds to steps 17, 18, 19 and 20.

[0033] On the other hand, when it is determined that the timer in the control holding state ends before the DTCH is assigned, the fourth step includes the twelfth step.

[0034] The twelfth step is a step in which the control unit of the MAC layer of the mobile station transitions to the stopped state or returns to the control holding state. As shown in the figure, the process returns from step S17 to step S11.

FIG. 4 is a flowchart showing a state transition of a control unit of the MAC hierarchy in the dedicated channel allocation method for packet transmission according to the embodiment of the present invention.

As shown in FIG. 4, the control unit of the MAC hierarchy can operate in four patterns of a hibernation state, a stop state, a control holding state, and an active state.

The hibernate state means a state in which the mobile station receives a pilot signal from the base station. In the hibernate state, since system information is not transmitted, power control is not performed and the amount of power dissipated is extremely small. Connectionless communication packets are arbitrarily transmitted via CTCH in a hibernate state. That is, the packet burst mode service is performed in this state. When a packet requesting the connection type communication service is generated, the control unit of the MAC hierarchy transitions to the stopped state. The stopped state means the initial state of the data service mode in which no dedicated channel (DCCH or DTCH) is assigned.

[0038] The control unit of the MAC hierarchy receives DCCH after transitioning to the stopped state. If the timer in the stopped state expires before receiving the DCCH, the control unit of the MAC hierarchy does not transition to the control holding state until the DCCH is received. The control holding state means the state after receiving the DCCH until the DTCH is assigned.

[0039] When the DTCH is assigned to the packet, the control unit of the MAC hierarchy transitions to the active state. However, if the timer in the control holding state ends before receiving the DTCH, the control unit in the MAC hierarchy returns to the stopped state again.

[0040] In the active state, the packet in data service mode is transmitted via the DTCH assigned to the packet. The amount of power dissipated in the active state is the largest of the four patterns. Packet transmission should be completed before the active timer expires. When the timer in the active state expires, the control unit in the MAC hierarchy returns to the control holding state again.

The equation for the probability that a packet will occur in data service mode is λ._D = λ × P_DIs. Here, λ indicates the probability that connection-type communication packet data requesting the packet data service mode will occur, and P_DIndicates the probability that a packet will occur in the control section of the MAC hierarchy. Packet is λ_DWhen it occurs with the probability of, the control unit of the MAC hierarchy of the mobile station determines the service option of the packet. In the case of a connection-type communication packet, the control unit of the MAC layer requests that the control unit of the MAC layer of the base station be assigned DCCH via the physical layer of the mobile station in the stopped state.

[0042] If DCCH is assigned, the control unit of the MAC hierarchy transitions to the control holding state, and then DTCH is λ._DIt is assigned with the probability of. Where λ_DIndicates the DCCH requirement rate. When the DTCH is assigned, the control unit of the MAC hierarchy transitions to the active state and transmits the packet via the assigned DTCH.

[0043] The packet is time T_ADuring, it is transmitted in the active state. Time T_AAfter that, the control unit of the MAC hierarchy returns to the control holding state. This time T_AIndicates the value of the system timer in the active state.

[0044] Then, time T_CJudges whether or not has passed, and time T without DTCH being assigned_CAfter that, the control unit of the MAC hierarchy transitions to the stopped state. Here, time T_SIndicates the value of the system timer in the stopped state.

[0045] Two patterns of state transitions can be assumed in the hibernate state in which the packet burst mode service is performed. One is the retransition to the first self-state, that is, the state in which the packet burst mode is held, and the other is the transition to the stopped state, that is, the transition to the data service mode. The probability of transitioning to data service mode is P_DIs. When a connection-type communication packet is generated, the control unit of the MAC layer immediately transitions to the data service mode. Therefore, the probability of transitioning to the first self-state is (1-P._D), That is, the probability that a connectionless communication packet will occur. When a connectionless communication packet is generated, the control unit of the MAC layer stays in the packet burst mode.

[0046] In the stopped state, three patterns of state transitions can be assumed. One of them is λ_DThis is the case where DCCH is assigned with the probability of and transitions to the control holding state. The other two patterns are the case of re-transitioning to the second self-state, that is, the stopped state, and the case of transitioning to the dormant state, respectively, if DCCH is not assigned.

[0047] The value time T of the timer in the stopped state until DCCH is assigned._SElapses. Time T_SAfter that, the control unit of the MAC hierarchy transitions to the hibernate state. If DCCH is not assigned, the control part of the MAC hierarchy will be time 1 / T_SThe probability of transitioning to hibernation every time and not being assigned DCCH is (1-λ)._D). Therefore, the probability of transitioning to hibernation is (1-λ)._D) / T_SAnd the probability of re-transitioning to the second self-state is (1-probability of not being assigned DCCH-probability of transitioning to dormant state), that is, (1-λ)._D) (1-1 / T_S).

[0048] In the control holding state, three patterns of state transitions can be assumed. One of them is μ_DThis is the case when DTCH is assigned with the probability of and transitions to the active state. The other two patterns are the case where the DTCH is not assigned and the state re-transitions to the third self state, that is, the control holding state, and the case where the state transitions to the stopped state, respectively.

[0049] Timer value time T in control hold state until DTCH is assigned_CElapses. Time T_CAfter that, the control unit of the MAC hierarchy transitions to the stopped state. If DTCH is not assigned, the MAC hierarchy control unit will time 1 / T_CThe probability that DTCH will not be assigned after transitioning to the stopped state is (1-μ)._D). Therefore, the probability of transitioning to the stopped state is (1-μ)._D) / T_CAnd the probability of transitioning to the third self-state again is (1-probability of not being assigned DTCH-probability of transitioning to the stopped state), that is, (1-μ)._D) (1-1 / T_C).

[Effect of the Invention] As described above, according to the dedicated channel allocation method for packet transmission according to the present invention, when packet data is transmitted between a mobile station and a base station, a connection type communication packet is used. By allocating a dedicated channel to, it is possible to maintain a rapid packet processing speed regardless of an increase in the amount of packet generation.

[0051] More specifically, if 100 users request the data service mode with a probability of 0.8, the average delay in the packet transmission method is not so different from that of the conventional method, but the processing rate is such that packets are generated. It has the excellent effect of being able to hold 54% or more at all times regardless of the amount.

BRIEF DESCRIPTION OF THE DRAWINGS [Fig. 1] A concept showing a stacked structure of lower CDMA protocol layers between a mobile station and a base station in a dedicated channel allocation method for packet transmission according to an embodiment of the present invention. It is a figure.

FIG. 2 is a flowchart showing an operation between each layer control unit that performs a corresponding function of each protocol element in each layer shown in FIG.

FIG. 3 is a flowchart showing a dedicated channel allocation method for packet transmission according to the embodiment of the present invention.

FIG. 4 is a flowchart showing a state transition of a control unit of a MAC hierarchy in a dedicated channel allocation method for packet transmission according to an embodiment of the present invention.