Communication stations and methods for transmitting on a random access channel

Abstract

Example communication stations and methods for transmitting on a random access channel (RACH) in wireless networks are disclosed herein. An example method for transmitting on an enhanced RACH by a device such that an initial access burst is received in a single time slot by a wireless network involves determining a timing advance, the timing advance being associated with a serving cell. The example method also involves transmitting, using the determined timing advance, the initial access burst, on the enhanced RACH, that includes at least one of an identifier or user data.

What is claimed is: 
     
         1 . A method for transmitting on an enhanced random-access channel (RACH) by a device such that an initial access burst is received in a single time slot by a wireless network, the method comprising:
 determining a timing advance, the timing advance being associated with a serving cell; and   transmitting, using the determined timing advance, the initial access burst, on the enhanced RACH, that includes at least one of an identifier or user data.   
     
     
         2 . The method of  claim 1 , wherein the method is performed in a time-division multiple access (TDMA) communication system,
 wherein the method further comprises receiving a notification from a base station indicating that the enhanced RACH is configured for initial access transmissions, the notification including parameters defining the enhanced RACH including an identification of time-slots of TDMA frames that comprise the enhanced RACH, and   wherein the user data includes data having a network destination.   
     
     
         3 . The method of  claim 2  wherein the enhanced RACH is a secondary RACH,
 wherein a primary RACH is provided by the base station for transmission of access request messages by devices requesting assignment of a channel resource, and 
 wherein when the timing advance is unknown, the method further comprises: 
 using the primary RACH for transmitting access request messages for an assignment of a channel resource for a subsequent transmission of data; and 
 refraining from transmitting the initial access burst on the enhanced RACH. 
 
     
     
         4 . The method of  claim 3  wherein the primary RACH is to be used by the devices without an enhanced-RACH capability for transmitting access request messages,
 wherein the enhanced RACH is to be used by the devices having the enhanced-RACH capability when an amount of data for transmission does not exceed an amount that can be transmitted in a single burst for receipt within a single time slot on the enhanced RACH. 
 
     
     
         5 . The method of  claim 4  wherein when the amount of data for transmission exceeds an amount that can be transmitted in a single burst for receipt within a single time slot on the enhanced RACH, the method further comprises either:
 transmitting the data in multiple initial access bursts on the enhanced RACH based on the timing advance; or 
 transmitting an initial access request message on the primary RACH to request an assignment of a channel resource for a subsequent transmission of the data. 
 
     
     
         6 . The method of  claim 4  wherein the initial access burst is triggered by an upper-level layer of the device that has data to send to the network destination when the device has no assigned resources on a data channel for data transmission, and
 wherein when the amount of data for transmission exceeds a predetermined amount, or when quality-of-service (QoS) requirements for the data do not meet one or more predetermined criteria able to be met by the enhanced RACH, the method comprises: 
 refraining from transmitting the initial access burst on the enhanced RACH; and 
 requesting a temporary block flow for transmission of the data. 
 
     
     
         7 . The method of  claim 1  wherein the initial access burst transmitted on the enhanced RACH comprises an enhanced access burst in which at least some guard bits are replaced with bits conveying the data, and
 wherein the enhanced access burst is configured in accordance with a legacy access burst structure. 
 
     
     
         8 . The method of  claim 1  wherein the data transmitted by the device on the enhanced RACH comprises data having either a low-latency requirement or a quality of service level requirement that does not require an acknowledgement from a radio access network. 
     
     
         9 . The method of  claim 1  wherein transmissions on the enhanced RACH are to be configured in a normal-burst format,
 wherein the method further includes the device configuring the initial access burst for transmission on the enhanced RACH in accordance with a normal-burst format, and 
 wherein transmission of the initial access burst in the normal-burst format is no greater than a time-slot of the enhanced RACH. 
 
     
     
         10 . The method of  claim 9  wherein the device is a non-mobile communication station having a fixed geographic location,
 wherein a same timing advance is to be used for the non-mobile communication station for small data transfers over the enhanced RACH, and 
 wherein the small data transfers comprise machine-type communications (MTC). 
 
     
     
         11 . The method of  claim 2  wherein the base station and the device operate within the wireless network,
 wherein prior to receiving the notification from the base station of the enhanced RACH, the method comprises the device indicating to the wireless network whether or not the device has enhanced-RACH capability to support small data transmission on the enhanced RACH and provides the wireless network with a full-length identifier that uniquely identifies the device, 
 wherein the notification received from the base station includes the identifier to identify the device from other devices with enhanced-RACH capability, and 
 wherein the initial access burst includes the identifier. 
 
     
     
         12 . The method of  claim 2  wherein the base station establishes the enhanced RACH by sending an enhanced-RACH notification message on a control channel using a single block packet downlink assignment procedure. 
     
     
         13 . The method of  claim 1  further comprising transmitting enhanced RACH capability information associated with the device in the initial access burst. 
     
     
         14 . A tangible computer readable medium having instructions stored thereon that, when executed, cause a machine to implement the method as defined in  claim 1 . 
     
     
         15 . A device comprising a processor configured to:
 configure an initial access burst for transmission on an enhanced random-access channel (RACH) when a timing advance (TA) is known by the communication station, the initial access burst to include at least one of an identifier and user data; and   cause transceiver circuitry to transmit the initial access burst based on the timing advance to be received by a base station within a single time slot of the enhanced RACH.   
     
     
         16 . The device of  claim 15  wherein the device is configured to operate within a time-division multiple access (TDMA) communication system, and
 wherein the transceiver circuitry is further configured to receive a notification from the base station indicating that the enhanced RACH is configured for initial access transmissions, the notification including parameters defining the enhanced RACH including an identification of time-slots of TDMA frames that comprise the enhanced RACH, and 
 wherein the user data includes data having a network destination. 
 
     
     
         17 . The device of  claim 16  wherein the enhanced RACH is a secondary RACH,
 wherein a primary RACH is provided by the base station for transmission of access request messages by devices requesting assignment of a channel resource, and 
 wherein when the timing advance is unknown, the transceiver circuitry is further configured to: 
 use the primary RACH for transmitting access request messages for an assignment of a channel resource for a subsequent transmission of data; and 
 
       refrain from transmitting the initial access burst on the enhanced RACH.