WO2008152130A1

WO2008152130A1 - Apparatus, method and computer program product providing control of system information decoding

Info

Publication number: WO2008152130A1
Application number: PCT/EP2008/057475
Authority: WO
Inventors: Volker Breuer; Jarkko T. Koskela; Sari Nielsen; Benoist Sebire; Antti Toskala
Original assignee: Nokia Siemens Networks Oy
Current assignee: Nokia Solutions and Networks Oy
Priority date: 2007-06-15
Filing date: 2008-06-13
Publication date: 2008-12-18
Anticipated expiration: 2009-12-15

Abstract

An exemplary embodiment in accordance with this invention is a method for mobility handling. The method includes detecting a neighbor cell. In response to determining that system information should be read, reading system information. The method may include detecting a flag in a transmission in a broadcast channel for a serving cell and determining whether the flag indicates reading system information of the neighbor cell is required; determining at least one measurement quantity for the neighbor cell and determining whether the at least one measurement quantity meets at least one threshold value; and determining whether a number of neighbor cell being read exceeds a threshold number. The system information may include a cell specific offset of the neighbor cell. The system information may be included in a measurement report of neighbor cells or used for ranking the neighbor cells for re-selection. Apparatus and computer readable media are also disclosed.

Description

APPARATUS, METHOD AND COMPUTER PROGRAM PRODUCT PROVIDING CONTROL OF SYSTEM INFORMATION DECODING

TECHNICAL FIELD:

The exemplary and non-limiting embodiments of this invention relate generally to wireless communication systems, methods, devices and computer program products and, more specifically, relate to techniques for mobility handling in E-UTRAN.

BACKGROUND :

Various abbreviations that appear in the specification and/or in the drawing figures are defined as follows:

3GPP Third Generation Partnership Project

BCH broadcast channel

CSG closed subscriber group

DRX discontinuous reception

DTX discontinuous transmission

E-UTRA evolved UMTS terrestrial radio access

E-UTRAN evolved UMTS terrestrial radio access network eNB E-UTRAN Node B

LTE long term evolution of UTRAN

Node B base station

NW network

P-BCH primary broadcast channel

P-SCH primary shared channel PDA personal digital assistant RRC radio resource connection / control RSRP reference symbol received power S-SCH secondary shared channel SCH shared transport channel

UE user equipment, such as a mobile station or mobile terminal

UMTS universal mobile telecommunications system UTRAN UMTS terrestrial radio access network UTRAN-LTE Universal Terrestrial Radio Access

Network-LTE (may be referred to as 3.9G)

A proposed communication system known as evolved UTRAN (E-UTRAN, also referred to as UTRAN-LTE) is currently under discussion within the 3GPP.

A cell specific offset was agreed to be introduced on the P-BCH of each cell. This offset is preferably taken into account by the UE when performing measurements or ranking the cells for re-selection purposes. In a RRC_CONNECTED state, the offset is preferably read by the UE before reporting neighbor cells. In the RRC_IDLE state, the offset is preferably read by the UE before ranking. Additionally it may be necessary for UE to read other system information for CSG cells as it may be required that the UE checks access restrictions for CSG cells before reporting them to the NW and possibly avoiding measurements of cells that the UE does not have access rights for. In UMTS, the cell specific offset is provided in the intra-frequency neighbor cell list which does not exist in LTE. In UMTS, a UE first ranks the neighbor cell based upon if that neighbor cell is a suitable cell and a candidate for actual re-selection and afterwards (after the re-selection) the BCH of only that selected cell is decoded.

In LTE typically there is no intra-frequency neighbor cell list (at least a regular neighbor list for identifying a new neighbor cell) in the serving cell (for reducing the BCH load) . The BCH decoding of the neighbor is preferably performed prior to ranking and deciding whether to perform a re-selection or prior to measurement reporting, for example, in the handover preparation phase.

Reading the P-BCH from a neighbor cells before a measurement report can be sent causes the following problems: 1) extra delay for measurement reports in the intra-frequency cell case due to both P-BCH scheduling delays as well as possible decoding errors in a neighbor cell P-BCH reception; and 2) increased power consumption due to frequent P-BCH decoding.

This means that even if a cell is quickly detected using P-SCH and S-SCH, a problematic P-BCH decoding of that cell (for example, due to scheduling and interference situation) is likely to degrade handover performance and overall system performance due to delayed measurement reports and thus delayed handovers. The situations and delays are likely to become even more severe for terminals that have good neighbor cell detection performance as this means even worse radio conditions for decoding.

In addition to handover performance degradation, neighbor cell decoding is also likely to have a significant negative impact on terminal power consumptions during DRX/DTX operations (active and idle) . When weak cells are detected, UE power consumption increases as the UE is required to keep the receiver open for extended periods for P-BCH decoding. Thus, in terms of power consumptions, terminals with better cell identification performance suffer more.

Furthermore, a requirement to read the P-BCH from the neighboring cells also has an effect on cell reselection performance in idle mode. It seems that before the UE can make any cell reselection decisions, it needs to obtain a cell specific offset from detected intra- frequency cells. In the worst case, this means that the UE needs to read P-BCH from all detected cells (especially if significant differences in cell specific offset values need to be considered) . As discussed, some of the detected cells may be very weak and thus the time needed to decode the P-BCH of those cells may be significant. Particularly problematic is a need for reading other system information (e.g., SI, SU-I, or any other SU) , as it causes a significant need for a measurement gap, thus reducing possible data transmission in the camped cell. Also, power consumption in the UE is heavily increased when the UE is required to read the system information for multiple cells.

Furthermore, BCH decoding is more critical in LTE than in UMTS in general due to missing spreading gain, etc.

SUMMARY : The following summary provides exemplary and non- limiting examples in accordance with this invention.

An exemplary embodiment in accordance with this invention is a method for mobility handling. The method includes detecting a neighbor cell. Determining whether to read system information from a neighbor cell broadcast channel of the neighbor cell, and in response to determining that the system information should be read, reading the system information is included in the method.

A further exemplary embodiment in accordance with this invention is an apparatus for mobility handling. The apparatus includes a receiver and at least one processor. The receiver is configured to detect a neighbor cell. The at least one processor is configured to determine whether to read system information from a neighbor cell broadcast channel of the neighbor cell and, in response to determining that the system information should be read, to read the system information via the receiver.

An additional exemplary embodiment in accordance with this invention is a computer readable medium embodying a computer program product including program instructions which are operable to control a data processor for mobility handling. The program instructions include detecting a neighbor cell. Determining whether to read system information from a neighbor cell broadcast channel of the neighbor cell, and in response to determining that the system information should be read, reading the system information are included.

A further exemplary embodiment in accordance with this invention is an apparatus for mobility handling. The apparatus includes means for detecting a neighbor cell. First determining means for determining whether to read system information from a neighbor cell broadcast channel of the neighbor cell are included. The apparatus includes means for reading the system information in response to the first determining means determining that the system information should be read.

BRIEF DESCRIPTION OF THE DRAWINGS

In the attached Drawing Figures:

Figure 1 shows a simplified block diagram of various electronic devices that are suitable for use in practicing the exemplary embodiments of this invention.

Figure 2 shows a logic flow diagram in accordance with exemplary embodiment of a method, and a computer program product, in accordance of this invention.

Figure 3 shows a logic flow diagram in accordance with exemplary embodiment of a method, and a computer program product, in accordance of this invention.

Figure 4 shows a logic flow diagram in accordance with exemplary embodiment of a method, and a computer program product, in accordance of this invention.

Figure 5 shows a logic flow diagram in accordance with exemplary embodiment of a method, and a computer program product, in accordance of this invention.

DETAILED DESCRIPTION The exemplary embodiments of this invention pertain generally to mobility handling in E-UTRAN (3GPP Release 8) . Mobility is based on measurements made by the UE. In the RRC_CONNECTED state, the UE identifies, measures, and reports neighbor cells for handover purposes. In the RRC_IDLE state, the UE identifies, measures, and ranks the cells for cell reselection purposes. The exemplary embodiments of this invention provide a means to overcome the problems listed above, among other advantages.

In one embodiment in accordance with this invention, a flag on the P-BCH indicates whether neighbor cell P-BCH decoding is requested. Additionally, a second flag may be used for indicating the need for reading other system information (e.g., SI, SU-I, etc.) of the neighbor cell (s) . The same flag can be used for indicating a request to read the P-BCH and/or the other system information of the neighbor cell (s) .

In another embodiment, a quality and/or signal strength threshold indicates when the UE selectively performs the decoding of the P-BCH and/or the other system information of the neighbor cell (s) .

In a further embodiment, an absolute number of neighbor cells from which the UE reads the P-BCH and/or the other system information is used. Combinations of these alternatives may be considered. For example when there are many cells which are above a quality threshold, the UE may read the P-BCH or the other system information from, for example, only the five best detected cells.

Reference is made to FIG. 1 for illustrating a simplified block diagram of various electronic devices that are suitable for use in practicing the exemplary embodiments of this invention. In FIG. 1, a wireless network 12 is adapted for communication with user equipment (UE 14) 14 via an access node (AN) 16. The UE 14 includes a data processor (DP) 18, a memory (MEM) 20 coupled to the DP 18, and a suitable RF transceiver (TRANS) 22 (having a transmitter (TX) and a receiver (RX)) coupled to the DP 18. The MEM 20 stores a program (PROG) 24. The TRANS 22 is for bidirectional wireless communications with the AN 16. Note that the TRANS 22 has at least one antenna to facilitate communication.

The AN 16 includes a data processor (DP) 26, a memory (MEM) 28 coupled to the DP 26, and a suitable RF transceiver (TRANS) 30 (having a transmitter (TX) and a receiver (RX)) coupled to the DP 26. The MEM 28 stores a program (PROG) 32. The TRANS 30 is for bidirectional wireless communications with the UE 14. Note that the TRANS 30 has at least one antenna to facilitate communication. The AN 16 is coupled via a data path 34 to one or more external networks or systems, such as the internet 36, for example. At least one of the PROGs 24, 32 is assumed to include program instructions that, when executed by the associated DP, enable the electronic device to operate in accordance with exemplary embodiments of this invention, as discussed herein. In general, the various embodiments of the UE 14 can include, but are not limited to, cellular phones, personal digital assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback appliances having wireless communication capabilities, Internet appliances permitting wireless Internet access and browsing, as well as portable units or terminals that incorporate combinations of such functions .

The MEMs 20, 28 may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory, as non-limiting examples. The DPs 18, 26 may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors

(DSPs) and processors based on a multi-core processor architecture, as non-limiting examples. The embodiments of this invention may be implemented by computer software executable by one or more of the DPs 18, 26 of the UE 14 and the AN 16, or by hardware, or by a combination of software and hardware.

In accordance with the exemplary embodiments of this invention, at least one bit is added to the P-BCH, which indicates to all UE 14s camped/served on/by that cell whether neighbor cell P-BCH decoding is required. Another bit/flag can indicate a need for reading other system information of the neighbor cell (s) . The bit indicating whether system information (e.g., SI, SU-I or any other SU) decoding is required can be frequency/cell dependant, for example, CSG (or home eNB) cells may require reading of system information and it would be beneficial to indicate such frequencies/cells which require system information reading of the neighbor cell (s) .

Preferably, the UE 14 is not mandated to always decode the P-BCH and/or other system information of the neighbor cell(s) for the ranking of the intra-frequency cells, as in most cases the offset may be zero (in case an operator does not intend to use it) . In scenarios or areas where only cells of the same kind are used (such as rural areas) , specific offset values may not be used, whilst in a dense urban setting the need for offset values in a limited range may exist.

Further in accordance with the exemplary embodiments of this invention of the UE 14 is constructed to contain circuitry configured to detect a particular bit flag of the P-BCH of the serving cell and circuitry configured to provide a determination of which detected neighbor cells from which to read the P-BCH and/or the other system information for determining an offset identification, where said determination is made based upon said bit (or flag) .

Based on the foregoing, it should be apparent that the exemplary embodiments of this invention provide for, in a non-limiting aspect thereof, a method, apparatus and computer program product, as show in Figure 2, for:

(A) detecting a neighboring cell;

(B) determining a particular bit flag of the P-BCH of the serving cell;

(C) determining if the bit flag indicates decoding is required; and

(D) based upon that determination, selectively decoding and reading the P-BCH and/or other system information for determining an offset identification.

Based on the foregoing, it should be apparent that the exemplary embodiments of this invention also provide for, in a non-limiting aspect thereof, an apparatus providing:

(A) means for detecting a neighboring cell; (B) means for determining a particular bit flag of the P-BCH of the serving cell;

(C) means for determining if the bit flag indicates decoding is required; and

(D) based upon that determination, means for selectively decoding and reading the P-BCH and/or other system information for determining an offset identification.

Further in accordance with the exemplary embodiments of this invention is a UE 14 constructed to contain circuitry configured to provide a stored threshold value; circuitry configured to provide at least one measurement quantity of a neighbor cell; and circuitry configured to provide a determination of which detected neighbor cells from which to decode and read the P-BCH and/or the other system information for determining an offset identification, where said determination is made based upon at least one of said measurement quantity. Based on the foregoing, it should be apparent that the exemplary embodiments of this invention provide for, in a non-limiting aspect thereof, a method, apparatus and computer program product, as show in Figure 3, for: (A) detecting a neighboring cell; (B) determining at least one measurement quantity for a neighbor cell;

(C) determining if the measurement quantity (or quantities) of a cell being read meets a given threshold; and (D) based upon that determination, selectively decoding and reading the P-BCH and/or other system information for determining an offset identification.

(A) means for detecting a neighboring cell;

(B) means for determining at least one measurement quantity for a neighbor cell;

(C) means for determining if said measurement quantity (or quantities) meets a given threshold; and

(D) means for decoding and reading the P-BCH and/or other system information, and based upon said determination selectively decoding and reading the P-BCH and/or other system information for determining an offset identification.

A further exemplary embodiment the UE 14 of the previous paragraphs is one where the TRANS 22 is configured to receive a signal via RRC (in dedicated signalling or via broadcast information) indicating a new threshold to be used and replacing the previous threshold with the new one. This can also be provided by means of a neighbor cell list, a list of neighbors for which the UE 14 is requested to consider. An additional exemplary embodiment the UE 14 of the previous paragraphs is one where there are separate threshold values for reading the P-BCH or the other system information. Separate thresholds can be defined against the serving cell level and neighbor cell level, for example based on reference symbol measurements, such as the RSRP (reference symbol received power) measurements. It should be appreciated that many other UE measurements can be used for these thresholds.

A further exemplary embodiment the UE 14 of the previous paragraphs is one that makes use of a relative decoding threshold. This can be a flexible level considering the maximum configured neighbor cell offset, i.e., the threshold may vary for different scenarios in dependence of the maximum offset introduced for any of the visible neighbors. Additionally, the relative offset threshold for decoding may depend on the actual setting of the maximum used offset.

An additional exemplary embodiment the UE 14 of the previous paragraphs is one that contains circuitry configured to create and/or sort a list of neighboring cells according to at least one measurement quantity for that cell.

Further in accordance with the exemplary embodiments of this invention is a UE 14 constructed to contain circuitry configured to provide a threshold value and configured to provide a determination of which detected neighbor cells from which to read the P-BCH and/or the other system information for determining an offset identification, where said determination is made based upon the threshold value above which no further cells are read.

Based on the foregoing, it should be apparent that the exemplary embodiments of this invention provide for, in a non-limiting aspect thereof, a method, apparatus and computer program product, as show in Figure 4, for:

(A) detecting a neighboring cell;

(B) determining the number of cells being read; (C) determining if the number of cells being read exceeds a given threshold; and

(D) based upon that determination, selectively decoding and reading the P-BCH and/or other system information for determining an offset identification. Based on the foregoing, it should be apparent that the exemplary embodiments of this invention also provide for, in a non-limiting aspect thereof, an apparatus providing:

(A) means for detecting a neighboring cell;

(B) means for determining the number of cells being read;

(C) means for determining if the number of cells being read exceeds a given threshold; and

(D) means for decoding the cell and reading the P-BCH and/or other system information, and based upon said determination selectively decoding and reading the P-BCH and/or the other system information for determining an offset identification.

A further exemplary embodiment the UE 14 of the previous paragraphs is one where the TRANS 22 is configured to receive a signal (either via dedicated or broadcast information) indicating a new threshold to be used and replacing the previous threshold with the new one. This can also be provided by means of a neighbor cell list, a list of neighbors for which the UE 14 is requested to consider.

Further in accordance with the exemplary embodiments of this invention is an access node 16 constructed to contain circuitry configured to produce at least one bit to be added to the P-BCH, which indicates whether neighbor cell P-BCH decoding is required, and circuitry configured to transmit said resulting P-BCH.

Further in accordance with the exemplary embodiments of this invention is an access node 16 constructed to contain circuitry configured to create a message, which indicates at least one signal or quality threshold value to be used by a UE 14 for determining which cells to decode for making mobility decisions, and circuitry configured to transmit said message.

An additional exemplary embodiment the access node 16 of the previous paragraphs is one where the transmitter is configured to transmit the message using dedicated signalling or via broadcast information.

A further exemplary embodiment the access node 16 of the previous paragraphs is one where a threshold value may be any of the following values: minimum measurement quantities of cells to be used; cell level; RSRP; etc. Based on the foregoing, it should be apparent that the exemplary embodiments of this invention provide for, in a non-limiting aspect thereof, a method, apparatus and computer program product, as show in Figure 5, for:

(A) creating a message, where said message indicates at least one signal or quality threshold value to be used by a UE 14 for determining which cells to decode for making mobility decisions; and

(B) transmitting said message.

(A) means for creating a message, where said message indicates at least one signal or quality threshold value to be used by a UE 14 for determining which cells to decode for making mobility decisions; and

(B) means for transmitting said message.

Further in accordance with the exemplary embodiments of this invention is an access node 16 constructed to contain circuitry configured to produce a neighbor cell list, which indicates a list of neighbor cells which a UE

14 is requested to consider and said list includes associated threshold information describing a maximum number of cells to decode, and circuitry configured to transmit said list.

A combination of these various alternative embodiments is also possible. For example, the threshold may be checked only if the introduced bit on the P-BCH indicates that P-BCH decoding of the neighbor cell is required.

An exemplary embodiment in accordance with this invention is a method for mobility handling. The method includes detecting a neighbor cell. Determining whether to read system information from a neighbor cell broadcast channel of the neighbor cell, and in response to determining that the system information should be read, reading the system information is included in the method. In a further embodiment of the method above, determining whether to read the system information includes detecting a flag in a transmission in a broadcast channel for a serving cell. Determining whether the flag indicates reading the system information of the neighbor cell is required and in response to determining that the flag indicates reading the system information of the neighbor cell is required, determining that the system information should be read is included. In an additional embodiment of any of the methods above, determining whether to read system information includes determining at least one measurement quantity for the neighbor cell. Determining whether the at least one measurement quantity meets at least one threshold value, and in response to determining that the at least one measurement quantity meets the at least one threshold value, determining that the system information should be read is included. The at least one threshold value may be a signal strength threshold and/or a signal quality threshold. The method may also include receiving the at least one threshold value from a serving access station.

In a further embodiment of any of the method above, determining whether to read system information includes determining whether a number of neighbor cell being read exceeds a threshold number and in response to determining that the number of neighbor cell being read does not exceed the threshold number, determining that the system information should be read. The method may also include receiving the threshold number from a serving access station.

In an additional embodiment of any of the methods above, reading the system information of the neighbor cell includes decoding a neighbor cell primary broadcast channel transmission. In a further embodiment of any of the method above, the method including in response to reading the system information, including the system information in a measurement report of neighbor cells. The method may also include transmitting the measurement report to an access station. The system information in the measurement report may be prioritizing.

In an additional embodiment of any of the methods above, the method including in response to reading the system information, ranking the neighbor cells for re- selection .

In a further embodiment of any of the methods above, the system information comprises a cell specific offset.

In an additional embodiment of the apparatus above, the at least one processor is further configured to detect a flag in a transmission in a broadcast channel for a serving cell via the receiver, to determine whether the flag indicates reading the system information of the neighbor cell is required and, in response to determining that the flag indicates reading the system information of the neighbor cell is required, to determine that the system information should be read.

In a further embodiment of any of the apparatus above, the at least one processor is further configured to determine at least one measurement quantity for the neighbor cell, to determine whether the at least one measurement quantity meets at least one threshold value and, in response to determining that the at least one measurement quantity meets the at least one threshold value, to determine that the system information should be read. The at least one threshold value may be a signal strength threshold and/or a signal quality threshold. The at least one processor is further configured to receive the at least one threshold value from a serving access station via the receiver.

In an additional embodiment of any of the apparatus above, the at least one processor is further configured to determine whether a number of neighbor cell being read exceeds a threshold number and, in response to determining that the number of neighbor cell being read does not exceed the threshold number, to determine that the system information should be read. The at least one processor may further be configured to receive the threshold number from a serving access station via the receiver .

In a further embodiment of any of the apparatus above, reading the system information of the neighbor cell includes decoding a neighbor cell primary broadcast channel transmission.

In an additional embodiment of any of the apparatus above, the at least one processor is further configured, in response to reading the system information, to include the system information in a measurement report of neighbor cells. The apparatus may also include a transmitter to transmit the measurement report to an access station. The at least one processor may further be configured to prioritize system information in the measurement report. In a further embodiment of any of the apparatus above, the at least one processor is further configured, in response to reading the system information, to rank the neighbor cells for re-selection.

In an additional embodiment of any of the apparatus above, the system information comprises a cell specific offset .

In a further embodiment of the computer readable medium above, determining whether to read the system information includes: detecting a flag in a transmission in a broadcast channel for a serving cell, determining whether the flag indicates reading the system information of the neighbor cell is required and, in response to determining that the flag indicates reading the system information of the neighbor cell is required, determining that the system information should be read.

In an additional embodiment of any of the computer readable media above, determining whether to read system information includes determining at least one measurement quantity for the neighbor cell, determining whether the at least one measurement quantity meets at least one threshold value and, in response to determining that the at least one measurement quantity meets the at least one threshold value, determining that the system information should be read. The at least one threshold value may be a signal strength threshold and/or a signal quality threshold. The program instructions may include receiving the at least one threshold value from a serving access station.

In a further embodiment of any of the computer readable media above, determining whether to read system information includes determining whether a number of neighbor cell being read exceeds a threshold number and, in response to determining that the number of neighbor cell being read does not exceed the threshold number, determining that the system information should be read. The program instructions may include receiving the threshold number from a serving access station.

In an additional embodiment of any of the computer readable media above, reading the system information of the neighbor cell includes decoding a neighbor cell primary broadcast channel transmission. In a further embodiment of any of the computer readable media above, the program instructions also include, in response to reading the system information, including the system information in a measurement report of neighbor cells. Transmitting the measurement report to an access station may also be included. The program instructions also include prioritizing system information in the measurement report.

In an additional embodiment of any of the computer readable media above, the program instructions also include, in response to reading the system information, ranking the neighbor cells for re-selection.

In a further embodiment of any of the computer readable media above, the system information comprises a cell specific offset.

In an additional embodiment of the apparatus above, the first determining means includes means for detecting a flag in a transmission in a broadcast channel for a serving cell and second determining means for determining whether the flag indicates reading the system information of the neighbor cell is required. The first determining means determines that that the system information should be read in response to the second determining means determining that the flag indicates reading the system information of the neighbor cell is required.

In a further embodiment of any of the apparatus above, the first determining means includes means for determining at least one measurement quantity for the neighbor cell and second determining means for determining whether the at least one measurement quantity meets at least one threshold value. The first determining means determines that the system information should be read in response to the second determining means determining that the at least one measurement quantity meets the at least one threshold value.

In an additional embodiment of any of the apparatus above, the first determining means includes second determining means for determining whether a number of neighbor cell being read exceeds a threshold number. The first determining means determines that the system information should be read in response to the second determining means determining that the number of neighbor cell being read does not exceed the threshold number.

In a further embodiment of any of the apparatus above, the apparatus includes means for including the system information in a measurement report of neighbor cells and means for transmitting the measurement report.

Based on the foregoing it should be apparent that the exemplary embodiments of this invention provide a method, apparatus and computer program product (s) to provide enhanced mobility handling in E-UTRAN.

It should be appreciated that at least some aspects of the exemplary embodiments of the inventions may be practiced in various components such as integrated circuit chips and modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be fabricated on a semiconductor substrate. Such software tools can automatically route conductors and locate components on a semiconductor substrate using well established rules of design, as well as libraries of pre-stored design modules. Once the design for a semiconductor circuit has been completed, the resultant design, in a standardized electronic format may be transmitted to a semiconductor fabrication facility for fabrication as one or more integrated circuit devices.

It should be appreciated that at least some of the features of the various non-limiting and exemplary embodiments of this invention may be used to advantage without the corresponding use of other features. As such, the foregoing description should be considered as merely illustrative of the principles, teachings and exemplary embodiments of this invention, and not in limitation thereof. For example, while the exemplary embodiments have been described above in the context of the E-UTRAN (UTRAN-LTE) system, it should be appreciated that the exemplary embodiments of this invention are not limited for use with only this one particular type of wireless communication system, and that they may be used to advantage in other wireless communication systems.

It should be noted that the terms "connected, " "coupled, " or any variant thereof, mean any connection or coupling, either direct or indirect, between two or more elements, and may encompass the presence of one or more intermediate elements between two elements that are "connected" or "coupled" together. The coupling or connection between the elements can be physical, logical, or a combination thereof. As employed herein two elements may be considered to be "connected" or "coupled" together by the use of one or more wires, cables and/or printed electrical connections, as well as by the use of electromagnetic energy, such as electromagnetic energy having wavelengths in the radio frequency region, the microwave region and the optical (both visible and invisible) region, as several non-limiting and non- exhaustive examples.

Further, the various labels, signal names, message names, etc. used are not intended to be limiting in any respect, as these may be identified by any suitable names .

Various modifications and adaptations to the exemplary embodiments of this invention may become apparent to those skilled in the relevant arts in view of the description, when read in conjunction with the accompanying drawings. However, any and all modifications will still fall within the scope of the non-limiting and exemplary embodiments of this invention.

Claims

CLAIMSWhat is claimed is:

1. A method comprising: detecting a neighbor cell; determining whether to read system information from a neighbor cell broadcast channel of the neighbor cell; and in response to determining that the system information should be read, reading the system information.

2. The method of claim 1, where determining whether to read the system information comprises: detecting a flag in a transmission in a broadcast channel for a serving cell; determining whether the flag indicates reading the system information of the neighbor cell is required; and in response to determining that the flag indicates reading the system information of the neighbor cell is required, determining that the system information should be read.

3. The method of claim 1, where determining whether to read system information comprises: determining at least one measurement quantity for the neighbor cell; determining whether the at least one measurement quantity meets at least one threshold value; and in response to determining that the at least one measurement quantity meets the at least one threshold value, determining that the system information should be read.

4. The method of claim 3, where the at least one threshold value is at least one of a signal strength threshold and a signal quality threshold

5. The method of claim 3, further comprises receiving the at least one threshold value from a serving access station (16) .

6. The method of claim 1, where determining whether to read system information comprises: determining whether a number of neighbor cell being read exceeds a threshold number; and in response to determining that the number of neighbor cell being read does not exceed the threshold number, determining that the system information should be read.

7. The method of claim 6, further comprises receiving the threshold number from a serving access station (16) .

8. The method of claim 1, where reading the system information of the neighbor cell comprises decoding a neighbor cell primary broadcast channel transmission.

9. The method of claim 1, further comprising in response to reading the system information, including the system information in a measurement report of neighbor cells .

10. The method of claim 9, further comprising transmitting the measurement report to an access station (16) .

11. The method of claim 9, further comprising prioritizing system information in the measurement report .

12. The method of claim 1, further comprising in response to reading the system information, ranking the neighbor cells for re-selection.

13. The method of claim 1, where the system information comprises a cell specific offset.

14. An apparatus comprising: a receiver (22) and at least one processor (18); where the receiver (22) is configured to detect a neighbor cell, and the at least one processor (18) is configured: to determine whether to read system information from a neighbor cell broadcast channel of the neighbor cell; and in response to determining that the system information should be read, to read the system information via the receiver (22) .

15. The apparatus of claim 14, where the at least one processor (18) is further configured: to detect a flag in a transmission in a broadcast channel for a serving cell via the receiver (22); to determine whether the flag indicates reading the system information of the neighbor cell is required; and in response to determining that the flag indicates reading the system information of the neighbor cell is required, to determine that the system information should be read.

16. The apparatus of claim 14, where the at least one processor (18) is further configured: to determine at least one measurement quantity for the neighbor cell; to determine whether the at least one measurement quantity meets at least one threshold value; and in response to determining that the at least one measurement quantity meets the at least one threshold value, to determine that the system information should be read.

17. The apparatus of claim 16, where the at least one threshold value is at least one of a signal strength threshold and a signal quality threshold

18. The apparatus of claim 16, where the at least one processor (18) is further configured to receive the at least one threshold value from a serving access station (16) via the receiver (22) .

19. The apparatus of claim 14, where the at least one processor (18) is further configured: to determine whether a number of neighbor cell being read exceeds a threshold number; and in response to determining that the number of neighbor cell being read does not exceed the threshold number, to determine that the system information should be read.

20. The apparatus of claim 19, where the at least one processor (18) is further configured to receive the threshold number from a serving access station (16) via the receiver (22) .

21. The apparatus of claim 14, where reading the system information of the neighbor cell comprises decoding a neighbor cell primary broadcast channel transmission.

22. The apparatus of claim 14, where the at least one processor (18) is further configured, in response to reading the system information, to include the system information in a measurement report of neighbor cells.

23. The apparatus of claim 22, further comprising a transmitter configured to transmit the measurement report to an access station (16) .

24. The apparatus of claim 22, where the at least one processor (18) is further configured to prioritize system information s in the measurement report.

25. The apparatus of claim 14, where the at least one processor (18) is further configured, in response to reading the system information, to rank the neighbor cells for re-selection.

26. The apparatus of claim 14, where the system information comprises a cell specific offset.

27. A computer readable medium (20) embodying a computer program product (24) including program instructions which are operable to control a data processor (18) to perform: detecting a neighbor cell; determining whether to read system information from a neighbor cell broadcast channel of the neighbor cell; and in response to determining that the system information should be read, reading the system information.

28. The computer readable medium (20) of claim 27, where determining whether to read the system information comprises : detecting a flag in a transmission in a broadcast channel for a serving cell; determining whether the flag indicates reading the system information of the neighbor cell is required; and in response to determining that the flag indicates reading the system information of the neighbor cell is required, determining that the system information should be read.

29. The computer readable medium (20) of claim 27, where determining whether to read system information comprises : determining at least one measurement quantity for the neighbor cell; determining whether the at least one measurement quantity meets at least one threshold value; and in response to determining that the at least one measurement quantity meets the at least one threshold value, determining that the system information should be read.

30. The computer readable medium (20) of claim 29, where the at least one threshold value is at least one of a signal strength threshold and a signal quality threshold.

31. The computer readable medium (20) of claim 29, further comprises receiving the at least one threshold value from a serving access station (16) .

32. The computer readable medium (20) of claim 27, where determining whether to read system information comprises : determining whether a number of neighbor cell being read exceeds a threshold number; and in response to determining that the number of neighbor cell being read does not exceed the threshold number, determining that the system information should be read.

33. The computer readable medium (20) of claim 32, further comprises receiving the threshold number from a serving access station (16).

34. The computer readable medium (20) of claim 27, where reading the system information of the neighbor cell comprises decoding a neighbor cell primary broadcast channel transmission.

35. The computer readable medium (20) of claim 27, further comprising in response to reading the system information, including the system information in a measurement report of neighbor cells.

36. The computer readable medium (20) of claim 35, further comprising transmitting the measurement report to an access station (16) .

37. The computer readable medium (20) of claim 35, further comprising prioritizing system information in the measurement report.

38. The computer readable medium (20) of claim 27, further comprising in response to reading the system information, ranking the neighbor cells for re-selection.

39. The computer readable medium (20) of claim 27, where the system information comprises a cell specific offset .

40. An apparatus comprising: means for detecting a neighbor cell; first determining means for determining whether to read system information from a neighbor cell broadcast channel of the neighbor cell; and means for reading the system information in response to the first determining means determining that the system information should be read.

41. The apparatus of claim 40, where the first determining means comprises: means for detecting a flag in a transmission in a broadcast channel for a serving cell; and second determining means for determining whether the flag indicates reading the system information of the neighbor cell is required, where the first determining means determines that that the system information should be read in response to the second determining means determining that the flag indicates reading the system information of the neighbor cell is required.

42. The apparatus of claim 40, where the first determining means comprises: means for determining at least one measurement quantity for the neighbor cell; and second determining means for determining whether the at least one measurement quantity meets at least one threshold value, where the first determining means determines that the system information should be read in response to the second determining means determining that the at least one measurement quantity meets the at least one threshold value .

43. The apparatus of claim 40, where the first determining means comprises: second determining means for determining whether a number of neighbor cell being read exceeds a threshold number, where the first determining means determines that the system information should be read in response to the second determining means determining that the number of neighbor cell being read does not exceed the threshold number .

44. The apparatus of claim 40, further comprising: means for including the system information in a measurement report of neighbor cells; and means for transmitting the measurement report.

45. The apparatus of claim 40, where the system information comprises a cell specific offset.