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Patent Issued for Method and Apparatus for Reporting Inter-Frequency Measurement Using RACH Message in a Mobile Communication System

May 21, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- From Alexandria, Virginia, VerticalNews journalists report that a patent by the inventors Jeong, Kyeong-In (Suwon-si, KR); Van Lieshout, Gert Jan (Middlesex, GB); Van Dervelde, Himke (Middlesex, GB); Kwak, No-Jun (Seoul, KR), filed on September 14, 2012, was published online on May 6, 2014.

The patent's assignee for patent number 8718018 is Samsung Electronics Co., Ltd. (Suwon-si, KR).

News editors obtained the following quote from the background information supplied by the inventors: "The present invention relates generally to a mobile communication system employing Code Division Multiple Access (CDMA). In particular, the present invention relates to a method and apparatus in which a terminal (or user equipment (UE)) reports measurement results to the system.

"A Universal Mobile Telecommunication Service (UMTS) system, which is an asynchronous 3.sup.rd generation (3G) mobile communication system employing Wideband Code Division Multiple Access (WCDMA) based on European Global System for Mobile Communications (GSM) and General Packet Radio Services (GPRS), provides consistent service that is capable of allowing telephone or computer users to transmit packet switched text, digitized voice, video, and multimedia data, at rates of about 2 Mbps all over the world. UMTS uses a virtual access technology, the so-called packet switched access based on a packet protocol such as Internet Protocol (IP), and can always access any other terminals in the network.

"In the 3.sup.rd Generation Project Partnership (3GPP), the standard for the asynchronous 3G mobile communication system, a Random Access Channel (RACH) which is an uplink common channel, is used for network access and control and transmission of short-length data. Such logical channels, for example a Dedicated Control Channel (DCCH), a Common Control Channel (CCCH), and a Dedicated Traffic Channel (DTCH), can be mapped to the RACH which is a transport channel.

"The RACH can be used for measurement reporting. That is, a UE includes measurement results indicating its measured radio strengths of other cells and other frequencies in a Radio Resource Control (RRC) message for signaling, transmitted to a Radio Network Controller (RNC) over the RACH. The measurement results are used by the system to determine whether a communication environment of a UE is good, and whether the UE is located in a handover region. Measurement control system information needed for performing inter-frequency and intra-frequency measurements is included in system information blocks (SIB) received from the RNC. The UE, in an idle mode or a connected mode, receives a SIB transmitted over a broadcast channel and acquires the measurement control system information therefrom.

"Table 1 and Table 2 below show, by way of example, a format of a RACH message for reporting inter-frequency measurement system information and inter-frequency measurement results, included in SIB11/12 to be used for reporting the inter-frequency measurement results. SIB11/12 includes measurement-related control information used in the current cell, wherein SIB11 is for an idle mode UE and SIB12 is for a connected mode UE. If there is no SIB12, the connected mode UE also refers to SIB11.

"Table 1 consists of Table 1a to Table 1c. Table 1a shows a format of `Inter-frequency measurement system information` included in SIB11/12. In Table 1a, an `Inter-frequency reporting quantity for RACH reporting` information element (IE) and a `maximum number of inter-frequency reported cells on RACH` IE are information for including inter-frequency measurement result values in the RACH message.

"TABLE-US-00001 TABLE 1a Inter-frequency measurement system information in SIB 11/12 Information Semantics Element/Group name Multi Type and reference description Inter-frequency cell info list Inter-frequency cell info list Inter-frequency reporting Inter-frequency quantity for RACH reporting quantity for Reporting RACH Reporting Maximum number of inter- Maximum number frequency of reported cells Reported cells on RACH on RACH

"TABLE-US-00002 TABLE 1b Inter-frequency reporting quantity for RACH reporting Information Element/ Semantics Group name Multi Type and reference description CHOICE mode >FDD >>Reporting quantity Enumerated(CPICH Ec/N0, CPICH RSCP, No report) >TDD >>Reporting quantity 1 to 2 list >>>Reporting quantity Enumerated(Timeslot ISCP, Primary CCPCH RSCP, No report)

"TABLE-US-00003 TABLE 1c Maximum number of inter-frequency reported cells on RACH Type Semantics Information Element/Group name Multi and reference description Maximum number of reported cells Integer(1 . . . 8) per for all reported non-used frequencies

"A `Reporting quantity` IE as shown in Table 1b indicates which reporting quantity is to be used when the inter-frequency measurement system information is transmitted over the RACH. For example, in a cell using Frequency Division Duplex (FDD), a chip-to-noise energy Ec/No of a Common Pilot Channel (CPICH) or a Receive Signal Code Power (RSCP) of the CPICH is used as a measurement result, or `No report` can be used to transmit no inter-frequency measurement result. A `Maximum number` IE as shown in Table 1c indicates the maximum number of cells to which the inter-frequency measurement results will be transmitted over the RACH.

"In transmitting the RACH message including the inter-frequency measurement results, if the `Reporting quantity` IE and the `Maximum number` IE are included in SIB11/12, the UE writes and includes as much inter-frequency measurement results as the `Maximum number` IE in the RACH message according to the `Reporting quantity` IE.

"For example, if the `Maximum number` IE is set to `2` and the `Reporting quantity` IE indicates an Ec/No of the CPICH, the UE includes an inter-frequency cell info list for 2 non-used frequency band cells and CPICH Ec/No for the non-used frequency band cells in the RACH message according to the measurement results for the non-used frequency band cells whose frequencies are different from the currently used frequency. Table 2 below shows an information format of the inter-frequency measurement results included in the RACH message.

"TABLE-US-00004 TABLE 2 Measured results on RACH Information Element/ Type and Semantics group name Multi reference description Measurement result for current cell Measurement results for 1 to monitored cells on non-used frequencies >Frequency info Frequency >Inter-frequency cell info measurement results >>CHOICE mode >>>FDD >>>>Primary CPICH info Primary CPICH info >>>>CHOICE measurement One spare quantity value is needed. >>>>>CPICH Ec/N0 Integer(0 . . . 49) In dB. According to CPICH_Ec/ No in [19]. Fourteen spare values are needed. >>>>>CPICH RSCP Integer(0 . . . 91) In dBm. According to CPICH_ RSCP_LEV in [19]. Thirty-six spare values are needed. >>>TDD >>>>Cell parameters Id Cell parameters Id >>>>Primary CCPCH RSCP Primary CCPCH RSCP info

"In this case, monitored cells consist of neighbouring cells.

"TABLE-US-00005 Condition Explanation DCCH This IE is optionally present when DCCH is used and not needed otherwise.

"As shown in Table 2, in reporting the inter-frequency measurement results over the RACH message, the UE includes as much `Frequency Info`, `Primary CPICH info` and `measurement quantity` as the `Maximum number` IE, transmitted through SIB11/12, in the RACH message, causing an excessive increase in the size of the RACH message.

"In addition, the UE includes the measurement results for the non-used frequencies in the RACH message even though the channels states of the non-used frequencies are bad. As is known to those skilled in the art, in order to transmit a message over the RACH, the UE should first send a request for RACH transmission approval to a base station (or Node B) and receive response information indicating approval of the RACH transmission from the Node B. Therefore, when RACH transmission approval requests are issued by a plurality of UEs, each UE may fail to obtain RACH transmission approval within the `Maximum number`. Nonetheless, if each UE unnecessarily transmits the measurement results on several non-used frequencies over the RACH, signaling overhead of the RACH may increase excessively.

"That is, in conventional measurement reporting, the measurement result information included in the RACH message includes many IEs, and there is no criterion for reporting, by the UE, the measurement results over the RACH, causing an increase in an uplink load.

"Accordingly, a need exists for a system and method for effectively and efficiently reporting measurement results."

As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventors' summary information for this patent: "An object of embodiments of the present invention is to substantially solve at least the above problems and/or disadvantages, and to provide at least the advantages below. Accordingly, embodiments of the present invention provide a method and apparatus in which a UE minimizes an information format of measurement reports transmitted over a RACH to thereby reduce signaling overhead of the RACH message.

"According to one aspect of embodiments of the present invention, a method is provided for reporting an inter-frequency measurement result using a random access channel (RACH) message in a mobile communication system. The method comprises the steps of receiving a system information block (SIB) comprising an inter-frequency cell information list for non-used frequency cells and a threshold from the system for inter-frequency measurement reporting, measuring signal strengths of signals received from the non-used frequency cells and comparing the measured signal strengths with the threshold and if there is any signal strength exceeding the threshold, acquiring at least one inter-frequency cell identifier (ID) indicating at least one non-used frequency cell having the signal strength exceeding the threshold from the inter-frequency cell information list, and including the at least one inter-frequency cell ID in the RACH message as inter-frequency measurement result information and transmitting the RACH message to the system.

"According to another aspect of embodiments of the present invention, a user equipment (UE) apparatus is provided for reporting an inter-frequency measurement result using a random access channel (RACH) message in a mobile communication system. The apparatus comprises a system information block (SIB) reception and analysis unit for receiving a SIB comprising an inter-frequency cell information list for non-used frequency cells and a threshold from the system for inter-frequency measurement reporting, a measurement unit for measuring signal strengths of signals received from the non-used frequency cells, a measurement report decision unit for comparing the measured signal strengths with the threshold and if there is at least one signal strength exceeding the threshold, determining to perform inter-frequency measurement reporting, and a measurement report unit for, if the measurement report decision unit determines to perforin inter-frequency measurement reporting, acquiring at least one inter-frequency cell identifier (ID) indicating at least one non-used frequency cell having the signal strength exceeding the threshold from the inter-frequency cell information list, including the at least one inter-frequency cell ID in the RACH message as inter-frequency measurement result information, and transmitting the RACH message to the system.

"According to another aspect of embodiments of the present invention, a method is provided for receiving inter-frequency measurement reporting using a random access channel (RACH) message in a mobile communication system. The method comprises the steps of transmitting a system information block (SIB) comprising an inter-frequency cell information list for non-used frequency cells and a threshold to each of controlled cells to control inter-frequency measurement reporting, receiving a RACH message from a user equipment (UE) located in one of the controlled cells, extracting at least one inter-frequency cell identifier (ID) corresponding to inter-frequency measurement result information from the RACH message, acquiring cell information corresponding to the extracted inter-frequency cell ID referring to the inter-frequency cell information list, and acquiring a measurement result indicating signal strength corresponding to the inter-frequency cell ID referring to at least one of the inter-frequency measurement result information and the threshold.

"According to yet another aspect of embodiments of the present invention, a radio network controller (RNC) is provided for receiving inter-frequency measurement reporting using a random access channel (RACH) message in a mobile communication system. The RNC comprises a system information system (SIB) generation and transmission unit for transmitting an SIB comprising an inter-frequency cell information list for non-used frequency cells and a threshold to each of controlled cells to control inter-frequency measurement reporting, a RACH receiver for receiving a RACH message from a user equipment (UE) located in one of the controlled cells and extracting at least one inter-frequency cell identifier (ID) corresponding to inter-frequency measurement result information from the RACH message, a cell index mapping unit for acquiring cell information corresponding to the extracted inter-frequency cell ID referring to the inter-frequency cell information list, and a measurement result analyzer for acquiring a measurement result indicating signal strength corresponding to the inter-frequency cell ID referring to at least one of the inter-frequency measurement result information and the threshold.

"According to still another aspect of embodiments of the present invention, a method is provided for reporting an inter-frequency measurement result using a random access channel (RACH) message in a mobile communication system. The method comprises the steps of receiving, by a control radio network controller (CRNC) that controls a current cell where a user equipment (UE) is located, a RACH message comprising at least one inter-frequency cell identifier (ID) for at least one non-used frequency cell as inter-frequency measurement result information from the UE, acquiring at least one cell information corresponding to the at least one inter-frequency cell ID, and transmitting an uplink signaling transfer message comprising an inter-frequency cell information list having the acquired at least one cell information, and the RACH message, to a serving radio network controller (SRNC) that controls radio resources of the UE.

"According to still another aspect of embodiments of the present invention, a method is provided for receiving inter-frequency measurement reporting using a random access channel (RACH) message in a mobile communication system. The method comprises the steps of receiving, by a serving radio network controller (SRNC) that controls radio resources of a user equipment (UE), an uplink signaling transfer message comprising a RACH message having at least one inter-frequency cell identifier (ID) for at least one non-used frequency cell, and at least one cell information corresponding to the at least one inter-frequency cell ID as inter-frequency measurement result information, from a control radio network controller (CRNC) that controls a current cell where the UE is located, and determining radio quality of the UE depending on the inter-frequency measurement result information and the at least one cell information."

For additional information on this patent, see: Jeong, Kyeong-In; Van Lieshout, Gert Jan; Van Dervelde, Himke; Kwak, No-Jun. Method and Apparatus for Reporting Inter-Frequency Measurement Using RACH Message in a Mobile Communication System. U.S. Patent Number 8718018, filed September 14, 2012, and published online on May 6, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=50&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=2459&f=G&l=50&co1=AND&d=PTXT&s1=20140506.PD.&OS=ISD/20140506&RS=ISD/20140506

Keywords for this news article include: Samsung Electronics Co. Ltd.

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Source: Electronics Newsweekly