Handover method for grant-free transmission, terminal device, and network device

• US 10,412,637 B2
• Filed: 12/22/2017
• Issued: 09/10/2019
• Est. Priority Date: 06/23/2015
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Yu, Rongdao
• Primary Examiner(s): Schwartz, Joshua L
• Application Number:
  US15/852,903
• Publication Number:
  US 20180124649A1
• Time in Patent Office: 627 Days
• Field of Search: 4554361
• CPC Class Codes: H04W 36/0005 Control or signalling for completing the hand-off
• CPC Class Codes: H04W 36/0072 of resource information of target access point
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 36/38 by fixed network equipment
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

The present disclosure provides a handover method for grant-free transmission, a terminal device, and a network device. The handover method includes: sending, by a first network device, a handover request message to a second network device to request to hand over a terminal device from the first network device to the second network device to perform grant-free transmission; receiving, by the first network device, a handover request acknowledgement message sent by the second network device to acknowledge handing over the terminal device from the first network device to the second network device to perform grant-free transmission; and sending, by the first network device, a handover instruction message to the terminal device to instruct the terminal device to transmit a signal to the second network device on a CTU resource in a grant-free transmission mode.

Claims

1. A handover method for grant-free transmission, comprising:

receiving, by a terminal device from a first network device, a handover instruction message used to instruct a handover of the terminal device from the first network device to a second network device to perform grant-free transmission, wherein the terminal device performs grant-free transmission using a first contention transmission unit (CTU) resource before handover, the handover instruction message comprises information about a second contention transmission unit (CTU) resource allocated by the second network device for transmitting uplink data in a grant-free transmission mode, and information about the second CTU resource comprises information about a time-frequency resource and a pilot; and

determining, by the terminal device according to the information about the second CTU resource carried in the handover instruction message, a quantity of CTUs in the contention access region and a CTU that is to be used in grant-free transmission performed after the terminal device is handed over to the second network device, wherein the CTU is determined according to the following formula;

Indx_CTU=Sig_i mod N_CTU,

wherein Indx_CTU is an index number of the CTU, mod represents a modulo operation, N_CTU represents the quantity of the CTUs in the contention access region, and Sig_i represents an index of a code resource of the terminal device; and

transmitting, by the terminal device according to the handover instruction message, uplink data to the second network device on the second CTU resource in the grant-free transmission mode.

2. The handover method according to claim 1, wherein

the second CTU resource is the same as the first CTU resource if when the second network device allows the terminal device to perform grant-free transmission using the first CTU resource;

or

the second CTU resource is different than the first CTU resource when the second network device forbids the terminal device to perform grant-free transmission using the first CTU resource.

3. A terminal device, comprising:

a transceiver, configured to;

receive a handover instruction message from a first network device, wherein the handover instruction message is used to instruct a handover of the terminal device from the first network device to a second network device to perform grant-free transmission, wherein the terminal device performs grant-free transmission using a first contention transmission unit (CTU) resource before handover, the handover instruction message comprises information about a second contention transmission unit (CTU) resource allocated by the second network device for transmitting uplink data in a grant-free transmission mode, and information about the second CTU resource comprises information about a time-frequency resource and a pilot; and

a processor, coupled to the transceiver and configured to;

determine, by the terminal device according to the information about the second CTU resource carried in the handover instruction message, a quantity of CTUs in the contention access region and a CTU that is to be used in grant-free transmission performed after the terminal device is handed over to the second network device, wherein the CTU is determined according to the following formula;

Indx_CTU=Sig_i mod N_CTU,

wherein Indx_CTU is an index number of the CTU, mod represents a modulo operation, N_CTU represents the quantity of the CTUs in the contention access region, and Sig_i represents an index of a code resource of the terminal device; and

the transceiver, configured to transmit, according to the handover instruction message, uplink data to the second network device on the second CTU resource in the grant-free transmission mode.

4. The terminal device according to claim 3, wherein

the second CTU resource is the same as the first CTU resource when the second network device allows the terminal device to perform grant-free transmission using the first CTU resource;

or

the second CTU resource is different than the first CTU resource when the second network device forbids the terminal device to perform grant-free transmission using the first CTU resource.

5. A non-transitory computer readable medium, wherein the medium includes instructions for instructing a terminal device to perform a handover method for grant-free transmission, comprising:

receiving, by a terminal device, a handover instruction message from a first network device, wherein the handover instruction message is used to instruct a handover of the terminal device from the first network device to a second network device to perform grant-free transmission, wherein the terminal device performs grant-free transmission using a first contention transmission unit (CTU) resource before handover, the handover instruction message comprises information about a second contention transmission unit (CTU) resource which is allocated by the second network device for transmitting uplink data in a grant-free transmission mode, and information about the second CTU resource comprises information about a time-frequency resource and a pilot; and

determining, by the terminal device according to the information about the second CTU resource carried in the handover instruction message, a quantity of CTUs in the contention access region and a CTU that is to be used in grant-free transmission performed after the terminal device is handed over to the second network device, wherein the CTU is determined according to the following formula;

Indx_CTU=Sig_i mod N_CTU,

wherein Indx_CTU is an index number of the CTU, mod represents a modulo operation, N_CTU represents the quantity of the CTUs in the contention access region, and Sig_i represents an index of a code resource of the terminal device; and

transmitting, by the terminal device according to the handover instruction message, uplink data to the second network device on the CTU resource in the grant-free transmission mode.

6. The non-transitory computer readable medium according to claim 5, wherein

the second CTU resource is the same as the first CTU resource when the second network device allows the terminal device to perform grant-free transmission using the first CTU resource;

or

the second CTU resource is different than the first CTU resource when the second network device forbids the terminal device to perform grant-free transmission using the first CTU resource.