摘要:
A base station transmits a random access response in response to a random access request (random access preamble) of a user equipment. The random access response includes information about a time when the random access request is transmitted and sequence number information of the random access request (random access preamble). The user equipment checks whether the received random access response is the response of the random access request transmitted by the user equipment, using the information about the time when the random access request is transmitted and the sequence number information included in the received random access response.
摘要:
A method for establishing RACH transmission to prepare against the frequency offset is disclosed. The method reduces the length of the RACH preamble even if the frequency offset exists, allows the RACH preamble to include a repeated structure (also called an iterative structure) or to use a specific sequence with less affect on the frequency offset, so that the Node-B can easily detect the RACH preamble. If different conditions are established in a high-speed UE and a low-speed UE, an amount of system overheads can be reduced as compared to another case in which an overall RACH condition has been prescribed for only the high-speed UE irrespective of the low-speed UE. And, the method determines whether the user equipment (UE) can estimate its speed according to the aforementioned RACH setup condition, and prescribes a detailed RACH access method according to the determined result.
摘要:
A method for transmitting a random access preamble to a base station at a user equipment (UE) includes generating the random access preamble from a Zadoff-Chu sequence having a length ‘N’ and a root index ‘M’, wherein the random access preamble is defined by a cyclic shift of the Zadoff-Chu sequence and transmitting the generated random access preamble to the base station via a random access channel, wherein the cyclic shift is given by using a variable corresponding to a Doppler shift of one subcarrier spacing, the variable given by using the root index ‘M’, and wherein the cyclic shift is differently given based on whether the variable is smaller than ⅓ of the length ‘N’.
摘要:
A method for establishing a cyclic shift sequence to provide against the frequency offset is disclosed. The method calculates a distance between a channel response position of the sequence and an alias channel response position caused by a frequency offset, calculates the number of cyclic shifts per group according to the calculated distance, and establishes the cyclic shift (CS)-applying interval. This method easily establishes a cyclic shift (CS) interval at a specific location having no overlapping by considering a channel response of a reception (Rx) sequence and an alias location of this reception (Rx) sequence, although a reception (Rx) signal is shifted by a channel delay spreading or a propagation delay irrespective of categories of a domain generating a sequence, so that it can greatly reduce the number of the detection errors and the false alarm rate. And, if a sequence of the cyclic shift (CS) is allocated to a cell having a frequency offset of more than a predetermined level, the present invention can minimize the influence of a frequency offset on a high-mobility cell.
摘要:
A wireless communication system is disclosed. A method for constructing a RACH preamble according to a cell radius of a base station (BS) irrespective of a guard time (GT) and a method for allocating the RACH preamble are disclosed. A method for constructing a preamble of a random access channel (RACH) includes acquiring time-length information of a predetermined cyclic prefix (CP) for each cell radius of a base station (BS), acquiring sequence time-length information of a single sequence or a repeated sequence, and constructing the preamble using the predetermined CP time-length information and the sequence time-length information, irrespective of a time length of a guard time (GT).
摘要:
A method for selecting a RACH preamble sequence for a high-speed mode and a low-speed mode is disclosed. In the case of acquiring sequence-type information to be used by a specific UE contained in a high-mobility region, a signaling reanalysis method under a general circular shift condition is disclosed, and a method for acquiring sequence-type information via the signaling using the sequence set configured by a restricted circular shift condition is also disclosed. Finally, a method for constructing a sequence set is disclosed.
摘要:
A method for a user equipment to transmit a random access preamble sequence to a base station includes transmitting the random access preamble sequence generated from a Constant Amplitude Zero Auto Correlation (CAZAC) sequence to the base station, wherein the CAZAC sequence is cyclic shifted according to one of applicable cyclic shift values defined considering a value (M) representing a Doppler shift of one subcarrier spacing and a cyclic shift unit length (T), and wherein when the value (M) meets a condition of ‘P*T≦M
摘要:
A signal mapping method and a signal transmission method applying a subcarrier shift method are described. A signal mapping method using shifted subcarriers includes shifting positions of data subcarriers by as much as a frequency band corresponding to half of spacing between data subcarriers on a frequency axis, and shifting positions of random access preamble subcarriers by as much as a frequency band corresponding to half of spacing between the data subcarriers and to a specific ratio of spacing between the random access preamble subcarriers, and mapping data and a random access preamble to the data subcarriers and the random access preamble subcarrier, respectively. Even when the spacing between the data subcarriers is a multiple of the spacing between the random access preamble subcarriers, DC distortion can be minimized.
摘要:
A method for establishing RACH transmission to prepare against the frequency offset is disclosed. The method reduces the length of the RACH preamble even if the frequency offset exists, allows the RACH preamble to include a repeated structure (also called an iterative structure) or to use a specific sequence with less affect on the frequency offset, so that the Node-B can easily detect the RACH preamble. If different conditions are established in a high-speed UE and a low-speed UE, an amount of system overheads can be reduced as compared to another case in which an overall RACH condition has been prescribed for only the high-speed UE irrespective of the low-speed UE. And, the method determines whether the user equipment (UE) can estimate its speed according to the aforementioned RACH setup condition, and prescribes a detailed RACH access method according to the determined result.
摘要:
A method for transmitting IDs of cells of a specific type as physical cell ID information in addition to existing cell ID information is disclosed. For transmission of the physical cell ID information, the number of cell IDs used in transmitting the existing cell ID information on a synchronization channel is increased or a part of existing cell IDs are reserved for transmitting the additional specific-cell ID information. If the number of cell IDs is to be increased, the number of cell ID groups related to a secondary synchronization channel is increased in a manner that removes ambiguity and collision, a cell ID related to a primary synchronization channel is added, which satisfies conjugate symmetry, information is transmitted based on a transmission timing relationship between a primary synchronization code and a secondary synchronization code, or a scrambling scheme is modified. When a part of the existing cell IDs are reserved, conjugate symmetry is also considered in relation to a primary synchronization channel and ambiguity and collision are also considered in relation to a secondary synchronization channel.