Preamble signature selection for contention based random access in mobile communication

Patent metadata

Field	Value
Publication number	US-10820344-B2
Application number	US-201916252485-A
Country	US
Kind code	B2
Filing date	Jan 18, 2019
Priority date	Jan 18, 2019
Publication date	Oct 27, 2020
Grant date	Oct 27, 2020

Abstract

Techniques and examples pertaining to reducing preamble collision in contention-based random access (CBRA) from a user equipment (UE) to a base station of a mobile communication network are described. A method for selecting a preamble signature may involve identifying a quantity of preamble signatures reserved for CBRA in the mobile communication network. The method may also involve performing a modulo computation based on a unique identifier of the UE and the quantity of preamble signatures. The method may also involve designating one of the preamble signatures as a chosen preamble signature based on a result of the modulo computation. The method may further involve initiating a random access procedure using the chosen preamble signature to establish a communication link between the UE and the base station.

First claim

What is claimed is:

1. A method performed by a user equipment (UE) of a mobile communication network, comprising:
identifying a quantity of a plurality of preamble signatures reserved for contention-based random access (CBRA) to a base station of the mobile communication network, wherein the plurality of preamble signatures comprises a first group of preamble signatures and a second group of preamble signatures;
performing a modulo computation based on a unique identifier of the UE and the quantity, wherein the modulo computation is performed based on determining of a message size margin, determining of a pathloss margin, or both;
designating one of the plurality of preamble signatures as a chosen preamble signature based on a result of the modulo computation, wherein the designating comprises selecting the chosen preamble signature from the first group of the preamble signatures or the second group of the preamble signatures based on at least one of a size of data and a pathloss of an uplink;
initiating a random access procedure using the chosen preamble signature to establish a communication link with the base station, wherein the communication link comprises the uplink via which the UE is to transmit the data to the base station;
determining the message size margin is positive in response to a first sum being less than a message size threshold, the first sum being a sum of the size of the data, a size of a Medium Access Control (MAC) header and a size of MAC control elements; and
determining the pathloss margin is positive in response to a second sum being less than a preamble power threshold, the second sum being a sum of the pathloss of the uplink, an initial transmit power of a preamble, a nominal power used for the uplink and a pathloss threshold offset.

2. The method of claim 1 , wherein the unique identifier is a Mobile Station International Subscriber Directory Number (MSISDN) or an Integrated Circuit Card Identifier (ICCID).

3. The method of claim 1 , wherein the identifying of the quantity comprises receiving a list of the plurality of preamble signatures that is broadcast by the base station.

4. The method of claim 1 , wherein the modulo computation comprises dividing the unique identifier by the quantity to obtain a remainder, and wherein the result of the modulo computation comprises the remainder.

5. The method of claim 1 , wherein:
the quantity is a sum of a first quantity and a second quantity, the first quantity being a quantity of the first group of preamble signatures, the second quantity being a quantity of the second group of preamble signatures, and
the modulo computation comprises dividing the unique identifier by the first quantity to obtain a remainder in response to determining the message size margin is positive or the pathloss margin is not positive,
the result of the modulo computation comprises the remainder, and
the designating of one of the preamble signatures as the chosen preamble signature comprises selecting the chosen preamble signature from the first group of the preamble signatures.

6. The method of claim 1 , wherein:
the quantity is a sum of a first quantity and a second quantity, the first quantity being a quantity of the first group of preamble signatures, the second quantity being a quantity of the second group of preamble signatures, and
the modulo computation comprises dividing the unique identifier by the second quantity to obtain a remainder in response to determining the message size margin is not positive and the pathloss margin is positive,
the result of the modulo computation comprises the remainder, and
the designating of one of the preamble signatures as the chosen preamble signature comprises selecting the chosen preamble signature from the second group of the preamble signatures.

7. The method of claim 1 , further comprising:
receiving a random access response from the base station in response to the initiating of the random access procedure;
transmitting a radio resource control (RRC) connection request to the base station in response to the receiving of the random access response; and
receiving a contention resolution from the base station for establishing the communication link in response to the transmitting of the RRC connection request.

8. The method of claim 1 , wherein the random access procedure is a first random access procedure, the method further comprising:
determining that the communication link has failed to establish by the first random access procedure; and
initiating, in response to the determining that the communication link has failed to establish by the first random access procedure, a second random access procedure in a following random access slot using the chosen preamble signature to establish the communication link with the base station.

9. The method of claim 1 , wherein the random access procedure is a first random access procedure, the method further comprising:
determining that the communication link has failed to establish by the first random access procedure; and
initiating, in response to the determining that the communication link has failed to establish by the first random access procedure, a second random access procedure using another preamble signature of the plurality of preamble signatures to establish the communication link with the base station.

10. The method of claim 1 , wherein the mobile communication network employs a Long-Term Evolution (LTE) mobile communication standard.

11. One or more non-transitory computer-readable media storing computer-executable instructions which, when executed by one or more processors of a user equipment (UE) of a mobile communication network, direct the UE to:
identify a quantity associated with a plurality of preamble signatures reserved for contention-based random access (CBRA) to a base station of the mobile communication network, wherein the plurality of preamble signatures comprises a first group of preamble signatures and a second group of preamble signatures;
perform a modulo computation based on a unique identifier of the UE and the quantity, wherein the performing of the modulo computation is based on determining of a message size margin, determining of a pathloss margin, or both;
designate one of the plurality of preamble signatures as a chosen preamble signature based on a result of the modulo computation, wherein the designating comprises selecting the chosen preamble signature from the first group of the preamble signatures or the second group of the preamble signatures based on at least one of a size of data and a pathloss of an uplink;
initiate a random access procedure using the chosen preamble signature to establish a communication link with the base station, wherein the communication link comprises the uplink via which the UE is to transmit the data to the base station;
determine the message size margin is positive in response to a first sum being less than a message size threshold, the first sum being a sum of the size of the data, a size of a Medium Access Control (MAC) header and a size of MAC control elements; and
determine the pathloss margin is positive in response to a second sum being less than a preamble power threshold, the second sum being a sum of the pathloss of the uplink, an initial transmit power of a preamble, a nominal power used for the uplink and a pathloss threshold offset.

12. The one or more non-transitory computer-readable media of claim 11 , wherein the unique identifier is a Mobile Station International Subscriber Directory Number (MSISDN) or an Integrated Circuit Card Identifier (ICCID).

13. The one or more non-transitory computer-readable media of cla

Assignees

• T Mobile Usa Inc

Inventors

• Jose Fnu Abin
• Kumar Ashwini

Classifications

• H04W74/0833 Primary

  Random access procedures, e.g. with 4-step access · CPC title

• H04W74/0838

  using contention-free random access [CFRA] · CPC title

• H04W76/18

  Management of setup rejection or failure · CPC title

• H04W74/08 Primary

  Non-scheduled access, e.g. ALOHA (hybrid access H04W74/02) · CPC title

• H04W74/0866

  using a dedicated channel for access · CPC title