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Terminal switching method, base station and communication system

A terminal switching and communication system technology, which is applied in the field of terminal switching, base stations and communication systems, can solve problems such as the inability to obtain HARQ synthesis effects, achieve the effect of shortening switching time and maintaining reception quality

Inactive Publication Date: 2014-09-24
MITSUBISHI ELECTRIC CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, even if Terminal A is provided with Grant again and retransmits, the combined effect of HARQ cannot be obtained.

Method used

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  • Terminal switching method, base station and communication system
  • Terminal switching method, base station and communication system
  • Terminal switching method, base station and communication system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0025] figure 1 It is a diagram showing an example of setting an inefficient retransmission window that occurs when the conventional technique is used. figure 2 It is a diagram showing an example of retransmission window setting when the terminal switching method according to Embodiment 1 of the present invention is applied. The communication system of this embodiment is constituted by a base station and a plurality of terminals, and HARQ is implemented between the base station and the terminals. In addition, the base station according to the present embodiment performs control to switch terminals for data transmission. Here, a resource release (Zero Grant) is instructed to a terminal to which radio resources are allocated (Grant is provided), and resources are provided to other terminals (Grant is provided), thereby switching the terminal that permits data transmission.

[0026] When performing control to switch a terminal for data transmission, the base station preferably p...

Embodiment approach 2

[0041] Figure 5 It is a diagram showing a terminal switching method according to Embodiment 2 of the present invention. In Embodiment 1, the retransmission waiting window is set at the starting point when the retransmission waiting window expires, but in this embodiment, the retransmission waiting window is updated every time a NACK signal is transmitted.

[0042] In the case of switching the terminal that permits data transmission from terminal A to terminal B, as in Figure 5 As shown, first, in the same manner as in Embodiment 1, a Zero Grant is sent to Terminal A, and a time point after a certain time (T1) elapses is set as the starting point #1, and a retransmission waiting window of a fixed time T2 is set. . In this embodiment, when the base station transmits a NACK signal (marked with a cross in the figure) before the retransmission waiting window set once expires, it resets the retransmission time length of T2 starting from the transmission of the NACK signal. send...

Embodiment approach 3

[0045] Figure 6It is a diagram showing a terminal switching method according to Embodiment 3 of the present invention. In Embodiment 1 and Embodiment 2, it is necessary to transmit Grant to the next terminal after completing the HARQ process of the permitted terminal before handover. However, when the communication quality between the licensed terminal and the base station before handover is extremely degraded, HARQ cannot be completed even if retransmission is repeated many times. Also, when only the HARQ process related to a specific terminal is in the retransmission wait state and retransmissions are repeated multiple times for this process, the HARQ processes of other terminals remain idle, conversely degrading the system throughput. In order to avoid such a situation, in the present embodiment, when the number of retransmissions reaches a predetermined threshold, a Grant is provided to the next terminal.

[0046] exist Figure 6 In the example of , set the threshold o...

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Abstract

A terminal switching method for switching terminals, in a communication system in which HARQ processing is performed, to which a base station grants a transmission permission, from a terminal A to a terminal B includes a step of notifying the terminal B of aborting of the transmission permission, a step of setting a time point at which an HARQ process whose state of the HARQ processing is a retransmission waiting state with the terminal A is performed as a virtual starting point, a step of setting a retransmission waiting window having a predetermined window length with the virtual starting point being regarded as its starting point, and a step of notifying the terminal B of the transmission permission when there is no HARQ process having the retransmission waiting state with the terminal A, wherein the virtual starting point setting and the window setting are repeated until there is no HARQ process having the retransmission waiting state with the terminal A.

Description

technical field [0001] The present invention relates to a terminal switching method, a base station, and a communication system in the case of switching a terminal for which the base station provides data transmission rights when the terminals share radio resources for communication in a communication system composed of a base station and a plurality of terminals. . Background technique [0002] In various recent communication systems, retransmission control (ARQ: Automatic Repeat reQuest, Automatic Repeat reQuest) is used as a method of correcting errors on the transmission path. For example, in the method called Stop and Wait (stop and wait) method, which is one of the retransmission methods, if the base station receives data from the terminal, it performs error detection after demodulation / decoding, and when it is judged that " If there is no error, an ACK signal is returned to the terminal, and when it is judged to be "error", a NACK signal is returned to the terminal. ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04W28/04H04L1/16H04L29/08
CPCH04L1/1887H04L69/324H04L1/0007H04L1/187H04L1/1803H04W28/04
Inventor 福井范行御宿哲也矢岛辰朗大矢根秀彦
Owner MITSUBISHI ELECTRIC CORP
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