BR112018010571B1 - RANDOM ACCESS CHANNEL SIGNALING ON A SHARED COMMUNICATION MEDIUM - Google Patents

Abstract

RANDOM ACCESS CHANNEL SIGNALING IN A SHARED COMMUNICATION MEDIUM. Techniques for random access channel signaling on a shared communication medium are disclosed. A broadcast message that includes information associated with a Physical Random Access Channel (PRACH) may be transmitted and received in one or more subframes in a portion configured for downlink signaling. The broadcast message may comprise a race type indicator, a timing advance indicator, or a combination thereof. The dispute type indicator can indicate whether the dispute is effective for transmission in PRACH. The timing advance indicator can indicate whether an uplink transmission offset is effective for transmission in the PRACH. Signaling over the PRACH may be transmitted and received in one or more subframes in a portion configured for uplink signaling.

Description

CROSS REFERENCE TO RELATED ORDER

[0001] The present application claims the benefit of Provisional Application No. U.S. 62/259,774, entitled "Random Access Channel Signaling on a Shared Communication Medium", filed on November 25, 2015, attributed to the present assignee and expressly incorporated into this document for reference in its entirety.

BACKGROUND

[0002] Aspects of the present disclosure relate generally to telecommunications and, more particularly, to operations on a shared communication medium and the like.

[0003] Wireless communication systems are widely installed to provide various types of communication content, such as voice, data, multimedia, among others. Typical wireless communication systems are multiple access systems capable of supporting communication with multiple users by sharing available system resources (e.g. bandwidth, transmission power, etc.). Examples of such multiple access systems include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division (OFDMA) and others. These systems are often installed in compliance with specifications such as Long Term Evolution (LTE) provided by the Third Generation Partnership Project (3GPP), Ultramobile Broadband (UMB) and Optimized Evolution Data (EV-DO) provided by the Partnership Project of Third Generation 2 (3GPP2), 802.11 provided by the Institute of Electrical and Electronics Engineers (IEEE), etc.

[0004] In cellular networks, "macrocell" access points provide connectivity and coverage to a large number of users throughout a certain geographic area. A macrogrid installation is carefully planned, designed and implemented to provide good coverage across the geographic region. To enhance specific geographic coverage for indoor or other environments, such as for residential homes and office buildings, additional "small cell", typically low-power access points have recently begun to be installed to supplement conventional macrogrids. Small cell access points can also provide incremental capacity growth, richer user experience, and more.

[0005] Small cell LTE operations, for example, have been extended into unlicensed frequency spectrum such as the Unlicensed National Information Infrastructure (U-NII) band used by Wireless Local Area Network (WLAN) technologies ). This extension of small cell LTE operation is designed to increase the spectral effectiveness and therefore the capacity of the LTE system. However, it may need to coexist with the operations of other Radio Access Technologies (RATs) that typically use the same unlicensed bands, notably IEEE 802.11x WLAN technologies generally referred to as "Wi-Fi".

SUMMARY

[0006] The following summary is an overview provided only to assist in describing various aspects of the disclosure and is provided only to illustrate aspects, and not to limit them.

[0007] In one example, a communication method is disclosed. The method may include, for example, receiving a broadcast message that includes information associated with a Physical Random Access Channel (PRACH) in one or more subframes in a portion configured for downlink signaling, wherein the broadcast message comprises a race type indicator, a timing advance indicator, or a combination thereof; determining whether the contest is effective for transmission on the PRACH based on the contest type indicator, whether an uplink transmission offset is effective for transmission on the PRACH based on the timing advance indicator, or a combination thereof; and transmitting signaling through the PRACH in one or more subframes in a portion configured for uplink signaling based on the determination.

[0008] In another example, a communication apparatus is disclosed. The apparatus may include, for example, at least one processor, at least one memory coupled to the at least one processor, and at least one transceiver. The at least one transceiver may be configured to receive a broadcast message that includes information associated with a PRACH in one or more subframes in a portion configured for downlink signaling. The broadcast message may comprise a race type indicator, a timing advance indicator, or a combination thereof. The at least one processor and the at least one memory may be configured to determine whether contention is effective for transmission on the PRACH based on the contention type indicator, whether an uplink transmission offset is effective for transmission on the PRACH based on the timing advance indicator or a combination thereof. The at least one transceiver may be further configured to transmit signaling via the PRACH in one or more subframes in a portion configured for uplink signaling based on the determination.

[0009] In another example, another communication device is revealed. The apparatus may include, for example, means for receiving a broadcast message that includes information associated with a PRACH in one or more subframes in a portion configured for downlink signaling, wherein the broadcast message comprises a contention type indicator. , a timing advance indicator or a combination thereof; means for determining whether the race is effective for transmission on the PRACH based on the race type indicator, whether an uplink transmission offset is effective for transmission on the PRACH based on the timing advance indicator, or a combination thereof ; and means for transmitting signaling through the PRACH in one or more subframes in a portion configured for uplink signaling based on the determination.

[0010] In another example, a non-transient or transient computer-readable medium is disclosed, which, when executed by at least one processor, causes the at least one processor to perform operations for communication. The computer-readable medium may include, for example, code for receiving a broadcast message that includes information associated with a PRACH in one or more subframes in a portion configured for downlink signaling, wherein the broadcast message comprises a message indicator. dispute type, a timing advance indicator or a combination thereof; code to determine whether the race is effective for transmission on the PRACH based on the race type indicator, whether an uplink transmission offset is effective for transmission on the PRACH based on the timing advance indicator, or a combination thereof ; and code for transmitting signaling through the PRACH in one or more subframes in a portion configured for uplink signaling based on the determination.

[0011] In one example, another method of communication is revealed. The method may include, for example, defining a race type indicator to indicate whether the race is effective for transmission on a PRACH, a timing advance indicator to indicate whether an uplink transmission offset is effective for transmission on the PRACH or a combination thereof; transmitting a broadcast message associated with the PRACH in one or more subframes in a portion configured for downlink signaling, wherein the broadcast message comprises the race type indicator, the timing advance indicator, or a combination thereof; and receiving signaling via the PRACH in one or more subframes in a portion configured for uplink signaling.

[0012] In another example, another communication device is disclosed. The apparatus may include, for example, at least one processor, at least one memory coupled to the at least one processor and at least one transceiver. The at least one processor and the at least one memory may be configured to define a race type indicator to indicate whether the race is effective for transmission in a PRACH, a timing advance indicator to indicate whether a transmission offset of uplink is effective for transmission in PRACH or a combination thereof. The at least one transceiver may be configured to transmit a broadcast message associated with the PRACH in one or more subframes in a portion configured for downlink signaling, wherein the broadcast message comprises the contention type indicator, the contention type indicator, the timing advance or a combination thereof, and to receive signaling via the PRACH in one or more subframes in a portion configured for uplink signaling.

[0013] In another example, another communication device is revealed. The apparatus may include, for example, means for defining a race type indicator to indicate whether the race is effective for transmission on a PRACH, a timing advance indicator to indicate whether an uplink transmission offset is effective for the transmission in PRACH or a combination thereof; means for transmitting a broadcast message associated with the PRACH in one or more subframes in a portion configured for downlink signaling, wherein the broadcast message comprises the race type indicator, the timing advance indicator, or a combination thereof same; and means for receiving signaling through the PRACH in one or more subframes in a portion configured for uplink signaling.

[0014] In another example, another non-transitory or transient computer-readable medium is disclosed, which, when executed by at least one processor, causes the at least one processor to perform the operations for communication. The computer-readable medium may include, for example, code to define a race type indicator to indicate whether the race is effective for transmission on a PRACH, a timing advance indicator to indicate whether an uplink transmission offset is effective for transmission in PRACH or a combination thereof; code for transmitting a PRACH-associated broadcast message in one or more subframes in a portion configured for downlink signaling, wherein the broadcast message comprises the race type indicator, the timing advance indicator, or a combination thereof. same; and code for receiving signaling through the PRACH in one or more subframes in a portion configured for uplink signaling.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The attached drawings are presented to assist in describing various aspects of the disclosure and are provided only for the illustration of the aspects, and not for the limitation thereof.

[0016] Figure 1 is a system-level diagram illustrating an exemplary wireless network environment.

[0017] Figures 2A to 2B illustrate an exemplary Time Division Duplex (TDD) frame structure.

[0018] Figure 3 is a resource map illustrating, in relevant part, exemplary subframe structures for a Physical Random Access Channel (PRACH).

[0019] Figure 4 illustrates an exemplary PRACH dispute parameter announcement message.

[0020] Figure 5 is a resource map illustrating an exemplary PRACH multiplexing scheme across access terminals.

[0021] Figures 6A to 6B illustrate exemplary special subframe structures that can be used for a short PRACH format.

[0022] Figure 7 is a resource map illustrating an exemplary PRACH multiplexing scheme for a short PRACH format.

[0023] Figure 8 illustrates an exemplary PRACH configuration parameter announcement message.

[0024] Figure 9 is a resource map illustrating an exemplary partial utilization scheme within a short PRACH format channel structure.

[0025] Figure 10 is a signaling flowchart that illustrates an exemplary adaptation of a random access procedure that can be used in conjunction with PRACH.

[0026] Figure 11 is a flowchart illustrating an exemplary method of communication in accordance with the techniques described in this document.

[0027] Figure 12 is a flowchart illustrating another exemplary method of communication in accordance with the techniques described in this document.

[0028] Figure 13 is a device-level diagram that illustrates exemplary components of an access point and an access terminal in greater detail.

[0029] Figure 14 illustrates an exemplary apparatus represented as a series of interrelated functional modules.

[0030] Figure 15 illustrates another exemplary apparatus represented as a series of interrelated functional modules.

DETAILED DESCRIPTION

[0031] The present disclosure relates, in general, to the management of random access channel signaling on a shared communication medium. To better harmonize with various contention procedures that may or may not be implemented in such a shared communication medium, one or more subframes designated to carry uplink information (e.g., special or uplink subframes) may be configured to provide information parameter information for a Physical Random Access Channel (PRACH), such as a race type indicator, a timing advance indicator, and other parameter information. PRACH can be configured with a short or long format in the time domain across a set or subset of symbol periods and can be interleaved across a set of subcarriers, in particular, resource blocks in the frequency domain. In some designs, one or more symbol periods may be reserved for opportunistic transmission after access to the communication medium is blocked, rather than being allocated directly to any access terminals. Various associated random access procedures are also provided to harmonize with PRACH, including, for example, transmitter and receiver processing, power control, temporary random access identifiers, and retransmission control.

[0032] More specific aspects of the disclosure are provided in the following description and related drawings directed to various examples provided for purposes of illustration. Alternative aspects can be developed without departing from the scope of the disclosure. Additionally, well-known aspects of the disclosure may not be described in detail or may be omitted so as not to obscure more relevant details.

[0033] Those skilled in the art will note that the information and signals described below can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols and chips that may be mentioned throughout the description below may be represented by voltages, currents, electromagnetic waves, magnetic particles or fields, optical particles or fields, or any combination thereof, depending partly on the particular application, partly on the desired design, partly on the corresponding technology, etc.

[0034] Additionally, many aspects are described in terms of sequences of actions to be performed, for example, by elements of a computing device. It will be recognized that various actions described herein may be performed by specific circuits (e.g., Application Specific Integrated Circuits (ASICs)), by program instructions that are executed by one or more processors, or by a combination of both. Additionally, for each of the aspects described in this document, the corresponding form of any of such aspects may be implemented, for example, as "logic configured to" perform the described action.

[0035] Figure 1 is a system-level diagram illustrating an exemplary wireless network environment shown by way of example including a "primary" Radio Access Technology (RAT) system 100 and a "RAT" system. competitor" 150. Each system may be composed of different wireless nodes, generally capable of receiving and/or transmitting over a wireless link, which includes information related to various types of communication (e.g. voice, data, services multimedia, associated control signaling, etc.). The primary RAT system 100 is shown including an access point 110 and an access terminal 120 in communication with each other via a wireless link 130. The concurrent RAT system 150 is shown including two concurrent nodes 152 in communication with each other. with each other via a separate wireless link 132 and may similarly include one or more access points, access terminals, or other types of wireless nodes. As an example, the access point 110 and the access terminal 120 of the primary RAT system 100 may communicate via the wireless link 130 in accordance with Long Term Evolution (LTE) technology or a variant thereof ( e.g., MuLTEfire, Licensed Assisted Access (LAA), etc.), while concurrent nodes 152 of concurrent RAT system 150 may communicate via wireless link 132 in accordance with Wi-Fi technology. It will be noted that Each system may support any number of wireless nodes distributed throughout a geographic region, wherein the illustrated entities are shown for illustration purposes only.

[0036] Except where otherwise indicated, the terms "access terminal" and "access point" are not intended to be specific or limited to any particular RAT. In general, access terminals can be any wireless communications device that allows a user to communicate over a communications network (e.g., a mobile phone, router, personal computer, server, entertainment device, device capable of for Internet of Things (IOT) / Internet of Everything (IOE), in-vehicle communication device, etc.), and can be alternatively called, in different RAT environments, as a User Device (UD), a Mobile Station ( MS), a Subscriber Station (STA), a User Equipment (UE), etc. Similarly, an access point can operate in accordance with one or several RATs in communicating with access terminals depending on the network in which the access point is installed, and can alternatively be called a Base Station (BS), a Network Node, a NodeB, an evolved NodeB (eNB), etc. Such an access point may correspond to a small cell access point, for example. "Small cells" generally refers to a class of low-power access points that may include or otherwise be called femtocells, picocells, microcells, Wireless Local Area Network (WLAN) access points, other small coverage area access points, etc. Small cells can be installed to supplement macrocell coverage, which can cover a few blocks within a neighborhood or several square kilometers in a rural environment, thus leading to improved signage, incremental capacity growth, user experience more enriched, among others.

[0037] Returning to Figure 1, the wireless link 130 used by the primary RAT system 100 and the wireless link 132 used by the concurrent RAT system 150 may operate over a shared communications medium 140. Such a communications medium type may be composed of one or more frequency, time and/or space communication resources (for example, encompassing one or more channels through one or more carriers). As an example, communication medium 140 may correspond to at least a portion of an unlicensed frequency band. Although different licensed frequency bands have been reserved for certain communications (for example, by a government entity such as the Federal Communications Commission (FCC) in the United States), some systems, in particular those employing small cell access points, have extended operation in unlicensed frequency bands such as the Unlicensed National Information Infrastructure (U-NII) band used by WLAN technologies including Wi-Fi.

[0038] Due to the shared use of communication medium 140, there is the potential for cross-link interference between the wireless link 130 and the wireless link 132. Additionally, some RATs and some jurisdictions may require a dispute or "Listen Before Talk (LBT)" for access to communication medium 140. As an example, a Clear Channel Assessment (CCA) protocol can be used, in which each device verifies, through medium detection, the absence of other traffic on a shared media before capturing (and in some cases reserving) the media for your own transmissions. In some designs, the CCA protocol may include separate CCA Preamble Detection (CCA-PD) and CCA Power Detection (CCA-ED) mechanisms to produce the communication medium for intra-RAT and inter-RAT traffic, respectively. The European Telecommunications Standards Institute (ETSI), for example, requires contention for all devices regardless of their RAT on certain media such as unlicensed frequency bands.

[0039] As will be described in greater detail below, the access point 110 and/or the access terminal 120 may be variously configured in accordance with the teachings herein to provide or otherwise support the random access channel signaling techniques discussed briefly above. For example, the access point 110 may include a random access channel manager 112 and the access terminal 120 may include a random access channel manager 122. The random access channel manager 112 and/or the channel manager random access channels 122 can be configured in different ways to manage the configuration of random access channels on the communication medium 140.

[0040] Figures 2A to 2B illustrate an exemplary Time Division Duplex (TDD) frame structure that can be implemented for the primary RAT system 100 on the communication means 140 to facilitate access to the communication means 140.

[0041] The illustrated frame structure includes a series of radio frames (RFs) that can be numbered according to a system frame number numerology (RFN, FN+1, RFN+2, etc.) and divided into respective subframes (SFs), which may also be enumerated for reference (e.g. SF0, SF1, etc.). Each respective subframe may be further divided into slots (not shown in Figures 2A through 2B), and the slots may be further divided into symbol periods. As an example, the LTE frame structure includes system frames that are divided into 1024 enumerated radio frames composed of 10 subframes each, which together constitute a system frame cycle (e.g., lasting 10, 24 s for 10 ms radio frames that have 1 ms subframes). Furthermore, each subframe may comprise two slots, and each slot may comprise six or seven symbol periods. Using a frame structure can provide more natural and effective coordination between devices than more ad hoc signaling techniques.

[0042] The exemplary frame structure of Figures 2A to 2B is TDD in the sense that each subframe can be variously operated at different times as a downlink (D), uplink (U) or special (S) subframe. . In general, the downlink subframes are reserved for transmitting downlink information from the access point 110 to the access terminal 120, the uplink subframes are reserved for transmitting the uplink information from the access terminal 120 to access point 110 and special subframes may include a downlink portion and an uplink portion separated by a guard period. The different arrangements of downlink, uplink, and special subframes can be called different TDD configurations. Some TDD configurations may have more downlink subframes and some may have more uplink subframes to accommodate different traffic scenarios.

[0043] In some designs, the frame structure may be "fixed" (as in Figure 2A), in the sense that the location of each subframe may be predetermined with respect to an absolute time, but may or may not be occupied by signaling. of primary RAT in any given case due to the contest procedure for accessing the communication medium 140. For example, if the access point 110 or the access terminal 120 is not successful in winning the contest for a given subframe, such subframe can be muted. In other designs, however, the frame structure may be "floating" (as in Figure 2B), in the sense that the type of each subframe (downlink, uplink, or special subframe) can be dynamically determined relative to the point wherein access to the communication medium 140 is protected (e.g., unobstructed CCA). For example, the actual start of a given frame (e.g., RFN+1) may be delayed by an absolute time until the access point 110 or the access terminal 120 can win the contest. In another example, the start of transmission is delayed until the communication medium 140 is secured and thereafter the TDD setting can be dynamically configured by the access point 110 (e.g., the next 10 subframes can be designated as DDDDDUUUUU, DDUUUUUUUU, or a different combination of D (i.e., downlink), U (i.e., uplink), and S (i.e., special subframe)).

[0044] As will be described in greater detail below, one or more subframes designated to carry uplink information (e.g., any or all of the special or uplink subframes in the example of Figures 2A to 2B) can be configured to provide a physical layer waveform for random access signaling in the form of a Physical Random Access Channel (PRACH). Several associated random access procedures are also provided to harmonize with PRACH. Due to the shared nature of the communication medium 140, the PRACH subframe structure and associated random access procedures may be adapted in different ways to better facilitate random access to the access terminal 120 in accordance with any applicable contention rules. .

[0045] Figure 3 is a resource map illustrating, in relevant part, exemplary subframe structures for PRACH. As shown, in different designs, PRACH may be configured using a relatively long PRACH format that occupies all or substantially all of the symbol periods constituting the subframe (e.g., 14 symbol periods for a normal cyclic prefix) or a relatively short PRACH format that occupies a subset N of fewer than all the symbol periods constituting the subframe. It will be noted that the short PRACH is shown in Figure 3 as occupying the first N symbols of the subframe for illustration purposes only and that, in other designs, the short PRACH may occupy the last N symbols of the subframe, N intermediate symbols of the subframe, among others. .

[0046] In general, a long PRACH format may allow more signaling to be accommodated within a given subframe, while a short PRACH format may allow for more efficient resource utilization across the communication medium 140 — for example, due to the special exemptions for short broadcast durations. As discussed above, however, the rules of contention for the communication medium 140 may vary across frequency bands, geography, among others. In some installations, the access terminal 120 may transmit on the PRACH automatically, without competing for access to the communication medium 140. For example, current ETSI contention rules in Europe allow a certain fraction of transmissions (e.g., 5% ) follows without the need for dispute although dispute is otherwise generally required. In other installations, however, the access terminal 120 may be required to compete for access to the communication medium 140 to transmit on the PRACH. Consequently, in some designs, the access point 110 may advertise various contention-related parameters for the access terminal 120 to use in performing random access.

[0047] Figure 4 illustrates an exemplary broadcast message called, for illustration purposes, a PRACH dispute parameter announcement message. In the present example, the PRACH race parameter announcement message 400 includes, in relevant part, a race type indicator 402, a CCA threshold indicator 404, a CCA duration indicator 406, a timing 408 and any other indicators 410 as appropriate for a given implementation. It will be noted that the single PRACH 400 dispute parameter announcement message is shown for illustration purposes only, and that in different designs and scenarios the various indicators may be transmitted in different sets of messages, as separate individual messages, among others. or they may be omitted altogether, as appropriate.

[0048] The dispute type indicator 402 may be used to indicate whether and to what extent the dispute is effective for transmission in PRACH (e.g., through a predetermined category or the like that define different types of dispute). For example, the 402 dispute type indicator may indicate that no dispute is effective (e.g., called LBT of "Category 1"), that dispute without random backoff is effective (e.g., called LBT of "Category 2") , that random-backoff contention that has a fixed-size contention window is effective (e.g., called "Category 3" LBT), that random-backoff contention that has a variable-size contention window is effective (e.g. , called LBT "Category 4"), among others. Consequently, based on the contention type indicator 402, the access terminal 120 may selectively contest for access to the communication medium 140 for PRACH signaling, rather than being pre-programmed to perform or not perform the contention.

[0049] The CCA threshold indicator 404 may be used to indicate a power threshold used for CCA that is specific to the PRACH, which may be different from the threshold used for other channels (e.g., a Physical Uplink Shared Channel (PUSCH)). As an example, the power threshold for PRACH may be higher (i.e., communication medium 140 is detected busy at higher power thresholds) compared to PUSCH to promote more aggressive contention, as PRACH typically occurs less frequently and the impact of missed transmission opportunities is therefore more pronounced. The CCA 406 duration indicator can be used to indicate the duration of an associated dispute window for the dispute process.

[0050] Timing advance indicator 408 can be used to indicate whether (and, in some cases, to what extent) an uplink transmission offset is effective for transmission in the PRACH. This offset can be used for receiver alignment purposes. Accordingly, based on the timing advance indicator 408, the access terminal 120 may transmit and the access point 110 may receive PRACH signaling at a modified initial time relative to a subframe boundary (e.g., at a time earlier than what is commonly defined for PRACH by the TDD framework structure).

[0051] The PRACH race parameter announcement message 400 may be transmitted (e.g., broadcast) by the access point 110 and received by the access terminal 120 semi-statically, such as via Master Information Block (MIB) signaling. , System Information Block (SIB) signaling, among others.

[0052] Returning to Figure 3, each PRACH symbol period may encompass one or more Resource Blocks (RBs) formed from a set of subcarriers in the frequency domain. For frequency diversity, power usage efficiency, and to satisfy various channel occupancy requirements, PRACH-dedicated RBs can be interleaved across a corresponding channel bandwidth.

[0053] Figure 5 is a resource map illustrating an exemplary PRACH multiplexing scheme across access terminals. As shown, PRACH can be frequency division multiplexed by allocating different interleavings to different access terminals.

[0054] In the illustrated example, a first interleave (interleave #1) can be allocated to a first AT-1 access terminal (e.g., access terminal 120) and a second interleave (interleave #2) can be allocated to a second AT-2 access terminal. As an example, for a 20 MHz channel bandwidth with 100 RBs, a set of 10 RBs consisting of every 10th RB may be dedicated to the PRACH for access terminal 120. Other channels such as a Link Shared Channel Physical Uplink (PUSCH), a Physical Uplink Control Channel (PUCCH), etc., may occupy other intervening loops (not shown).

[0055] It will be noted that the one-to-one correspondence of the interleavings for the access terminals is shown for illustration purposes only, and that, in different designs and scenarios, more than one access terminal may be assigned to a given interleaving (for example, through code division multiplexing), a given access terminal may occupy more than one interleaving, among others. Additionally, it will be noted that each interlace may be completely or only partially occupied by the PRACH depending on the format (e.g., short or long) that is employed for the PRACH.

[0056] Returning again to Figure 3, it will be noted that the configuration of an uplink subframe for the PRACH is shown for illustration purposes only, and that a similar configuration can be applied to multiple uplink subframes, to other subframes that have a segment dedicated to uplink signaling (for example, a special subframe), among others. In particular, due to the occupancy of less than a full subframe, the short PRACH format may be provided through truncated subframes as special subframes. Still further, the access point 110 may simply provide a PRACH configuration of one or more subframes for transmitting PRACH and these subframes may not have any predefined type (e.g., DL (downlink) or UL (uplink)). The access point 110 may dynamically configure such subframes to be downlink or uplink and the access terminal 120 performing PRACH may not have prior knowledge of this when transmitting the PRACH.

[0057] Figures 6A to 6B illustrate exemplary special subframe structures that can be used for the short PRACH format. In the design of Figure 6A, the special subframe 610 is called a "type I" special subframe and divided into three portions, including a downlink portion 612, followed by a span portion 614, followed by an uplink portion 616. As shown, in this design, the PRACH may be located in the uplink portion 616 at the end of the special type I subframe 610. In the design of Figure 6B, the special subframe 620 is called a "type II" special subframe and again divided. into three portions, however, with a different temporal arrangement, including an uplink portion 622, followed by a span portion 624, followed by a downlink portion 626. As shown, in the present design, the PRACH can be located in the uplink portion 622 at the beginning of the special type II subframe 620. The length of each portion may be variable, including zero length, in different scenarios.

[0058] As further illustrated in Figures 6A to 6B, the location of the type I special subframe 610 and the type II special subframe 620 may be offset relative to each other within the frame structure to accommodate the different temporal arrangements of the portions of uplink/downlink. In particular, the special type I subframe 610 may be installed at the downlink to uplink transition boundary (e.g., between a burst of downlink subframes followed by a burst of uplink subframes) to align the uplink portion downlink portion 612 to a previous downlink subframe and to align the uplink portion 616 to a later uplink subframe (e.g., to minimize overhead associated with the transition). In contrast, the special type II subframe 620 can be installed at the edge of the uplink to downlink transition (e.g., between a burst of uplink subframes followed by a burst of downlink subframes) to align the uplink portion uplink portion 622 to a previous uplink subframe and to align the downlink portion 626 to a later downlink subframe (e.g., again, to minimize overhead associated with the transition).

[0059] Either way, the span portion 614 of the type I special subframe 610 or the span portion 624 of the type II special subframe 620 may be used for contention (e.g., CCA) for obtaining access to the communication medium 140, for timing advancement to handle propagation delays in TDD systems, or, in some installations, may be skipped as when the PRACH carries contention-free signaling. The special type II subframe 610 may be advantageous in such installations as the span portion 624 may instead be used for contention for future downlink subframes.

[0060] Figure 7 is a resource map illustrating an exemplary PRACH multiplexing scheme for a short PRACH format. As shown, PRACH can be frequency division multiplexed with other channels in different RB interleavings. In the present example, the PRACH is configured in a first interleave (interlace no. 1) and other interleaves are used for Sound Reference Signaling (SRS), certain PUSCH signaling, a short PUCCH, among others. Within the first interleave (interleave #1) used for the PRACH, different access terminals can be multiplexed, shown by way of example as a first access terminal AT-1 and a second access terminal AT-2 that uses both first symbol periods (e.g., through code division multiplexing) and a third AT-3 access terminal that uses the next two symbol periods.

[0061] As further shown in Figure 7, PRACH may be transmitted periodically in an anchoring subframe, which is largely guaranteed to be available (e.g., through aggressive contention) or opportunistically in non-anchoring subframes. . Anchoring subframes can be scheduled with different periodicities in different projects (e.g. every 10 ms, every 20 ms, etc.). Non-anchoring subframes can be transmitted between periodic anchoring subframes. The access point 110 may configure whether to use the non-anchoring subframes for opportunistic or non-opportunistic PRACH. The type of anchoring subframe (e.g., special subframe or uplink subframe) may be predetermined or dynamically configured by the access point 110. The access terminal 120 is configured with the time location of the anchoring subframes and symbols within the subframe for use for the short PRACH. Additionally or alternatively, the access point 110 may configure only non-anchoring subframes for the access terminal 120 to send PRACH. The access point 110 may dynamically reconfigure such subframes without requiring the access terminal 120 to be aware of the configuration to transmit PRACH.

[0062] In the illustrated example, the short PRACH is carried in a special subframe. In some implementations, however, the short PRACH can be ported into a regular uplink subframe with some modifications. For example, the last few symbols of a regular uplink subframe can be assigned to PRACH and the remaining symbols can be used to carry regular uplink data (e.g., PUSCH).

[0063] In some implementations, the access terminal 120 may be configured with location (time and frequency resources) permitted for the PRACH, but the actual subframe type may not be known in advance, i.e., the anchoring subframes do not need be predefined as special subframes or regular uplink subframes. Access terminal 120 may configure this particular subframe to be one of either type dynamically.

[0064] Figure 8 illustrates another exemplary broadcast message called, for illustration purposes, a PRACH configuration parameter announcement message. In the present example, the PRACH configuration parameter announcement message 800 includes, in relevant part, a duration/format indicator 802, an interleaving indicator 804, a sequence indicator 806, a PRACH duration/location indicator 808 and any other indicators 810 as appropriate for a given implementation. It will be noted that the single PRACH 800 configuration parameter announcement message is shown for illustration purposes only, and that in different projects and scenarios the various indicators may be transmitted in different sets of messages, as separate individual messages, among others. or they may be omitted altogether, as appropriate. As an example, it will also be noted that the PRACH 800 configuration parameter announcement message may be combined, in whole or in part, with the PRACH 400 dispute parameter announcement message.

[0065] Duration/format indicator 802 can be used to indicate the format (e.g., short or long) that is employed for the PRACH as well as any relevant duration information (e.g., the number of symbol periods occupied by a given short PRACH format). The interleaving indicator 804 can be used to indicate the allowed RB interleavings reserved for the PRACH. The sequence indicator 806 may be used to indicate the permitted preamble sequences reserved for the random access procedure. The PRACH duration/location indicator 808 may be used to indicate the location and duration of PRACH resources, such as through the starting position and length of a downlink portion of the subframe in which the PRACH is installed, if any. applicable (e.g., the downlink portion 626 at the end of the special type II subframe 620).

[0066] The PRACH configuration parameter announcement message 800 may be transmitted (e.g., broadcast) by the access point 110 and received by the access terminal 120 semi-statically, such as via MIB signaling, SIB signaling, etc. others.

[0067] Figure 9 is a resource map illustrating an exemplary partial utilization scheme within a short PRACH format channel structure. As shown, in some designs and scenarios, PRACH can be configured to reserve a greater number of resources than are utilized by access terminal PRACH Transmission Opportunities (TXOPs). This may provide, for example, superior PRACH capacity and facilitate opportunistic PRACH within a subframe to mitigate blocked TXOPs due to the shared nature of the communication medium 140.

[0068] In the illustrated example, as in the example of Figure 5, a first AT-1 access terminal (e.g., access terminal 120) may use a first interleave (interleave No. 1) and a second AT access terminal -2 can use a second interlace (#2 interlace). As an example, access terminals may choose one or more interleavings to use from among all interleavings configured for the PRACH in a random and pseudo-random manner. However, the first AT-1 access terminal and the second AT-2 access terminal may only use blocks of two symbol periods for their PRACH transmissions.

[0069] As shown, the first access terminal AT-1 and the second access terminal AT-2 may each compete for access to the communication means 140 (e.g., perform CCA) at some time before the start of the PRACH. In the illustrated example, the first access terminal AT-1 succeeds and transmits on its respective interlock #1 in the first two symbol periods of the PRACH. The second access terminal AT-2, however, is unsuccessful and prevented from transmitting on its respective #2 interleave for the first two PRACH symbol periods. The second access terminal AT-2 therefore competes again for access to the communication medium 140 at some later time within the PRACH. Finally, the second AT-2 access terminal succeeds and transmits on its respective #2 interleave for the next two PRACH symbol periods.

[0070] By reserving additional resources for the PRACH, an access terminal that is unable to gain access to the communication medium 140 at the start of the PRACH may be able to later opportunistically capture the communication medium 140 and complete the transmission within the PRACH. Typically an access terminal increases its transmission power through different PRACH attempts. However, for opportunistic transmission within a subframe, the increase in transmission power is not used.

[0071] In some implementations, when additional resources are reserved for PRACH and PRACH is transmitted without contention, access terminals may randomly choose an initial symbol period to send their PRACH preamble. For example, with 4 symbol periods reserved for PRACH and a preamble duration of 2 symbol periods, an access terminal may randomly choose to transmit the PRACH preamble at symbol 1 or symbol 3.

[0072] Returning to Figure 9, although partial utilization may be appropriate for some access terminals, other access terminals may utilize additional resources as necessary. For example, handoff access terminals or access terminals near the edge of the coverage region provided by access point 110 (e.g., that have a path loss greater than a threshold) may utilize resources that span periods of additional PRACH symbols to facilitate more robust transmission. In the illustrated example, a third interleave (interleave #3) and all of its associated symbol periods can be used by a third AT-3 access terminal under such conditions.

[0073] Figure 10 is a signaling flowchart that illustrates an exemplary adaptation of a random access procedure that can be used in conjunction with PRACH. In the present example, the access terminal 120 performs a contention-based random access procedure through the PRACH to gain access to the uplink resources provided by the access point 110.

[0074] Contention-based random access can be performed as a generally four-party procedure. Initially, the access terminal 120 may transmit a random access preamble (Msg1 1012), the format and PRACH time domain resource allocation of which may be indicated by a PRACH configuration index or the like. . In conjunction with the transmission of Msg1, the access terminal 120 may set a Random Access Response (RAR) timer (e.g., according to a ra-ResponseWindowSize parameter) and wait for a RAR message (Msg2 1014) on a common control channel (for example, a Physical Downlink Control Channel (PDCCH)). Upon receipt of Msg2 before the RAR timer expires, the access terminal 120 may cancel the RAR timer. Otherwise, access terminal 120 may retransmit Msg1 1012.

[0075] In Msg2, the access terminal 120 may receive the timing alignment value, resources (uplink grant), and a temporary identifier (e.g., Cell Radio Network Temporary Identifier (C-RNTI)) to be used in transmitting a Radio Resource Control (RRC) request (Msg3 1016). In conjunction with the transmission of Msg3, the access terminal 120 may set a Dispute Resolution (CR) timer (e.g., according to a mac-ContentionResolutionTimer parameter).

[0076] After transmission of Msg3, the access terminal 120 may monitor the common control channel for a CR message containing its temporary identifier (Msg4 1018) until the expiration of the CR timer. In conjunction with successful decoding of Msg4, access terminal 120 may cancel the CR timer (block 1028).

[0077] For harmonization with a short PRACH format as described herein, the access terminal 120 may select the random access preamble (Msg1 1012) from an allocated set of Demodulation Reference Signal (DMRS) sequences. ) in different ways (preamble transmission processing (TX) block 1022). The DMRS sequence used by access terminal 120 in different symbol periods within a given subframe may be identical or may be different. When they are different, the second DMRS sequence may be completely different (e.g., from a different root sequence) or may use a different cyclic shift from the original sequence. Additionally, for multiple PRACH attempts for Msg1 1012 transmission (e.g., when the access terminal 120 is unable to gain access to the communication medium 140 or when the access point 110 does not receive the PRACH correctly), the DMRS sequences used by access terminal 120 may be the same or different again. However, a different DMRS sequence can help reduce the probability of collision with other access terminals. As an example, the second DMRS sequence may be chosen to be a cyclic offset of the first DMRS sequence, wherein the cyclic offset to be used is a function of the PRACH attempt number.

[0078] For this part, the access point 110 may demodulate the random access preamble (Msg1 1012) in different ways (preamble receive processing block (RX) 1024). In general, the access point 110 may perform per-RB processing for PRACH DMRS sequences and non-coherent power matching via RBs. Within an RB, the access point 110 can perform various operations. As an example, access point 110 may perform independent processing across different symbol periods and non-coherent combination across symbol periods. As another example, the access point 110 may perform coherent detection of a second symbol period (e.g., by using a first symbol period to obtain a channel estimate and using that channel estimate for coherent demodulation of the signal sequence). DMRS of the second symbol period) and determine the peak correlation value. As another example, access point 110 may perform coherent processing within a symbol period (e.g., cross-correlation of the first symbol period with a known preamble segment, cross-correlation of the second symbol period with the known preamble, and estimating channel and coherently/non-coherently combined across two symbols and obtaining the peak correlation value).

[0079] In certain systems, a narrowband PRACH waveform may be used for transmission of the random access preamble (Msg1 1012) (e.g., with the use of only one or a closely spaced subset of RB interleaves) . However, regulations in the communication medium 140 may restrict power for narrowband transmission — that is, narrowband transmissions may need to comply with certain power spectral density limits. To facilitate the use of a narrowband PRACH waveform, the access point 110 may, in some cases, additionally advertise an (optional) PRACH transmit power parameter message 1026 separately indicating the maximum allowable transmit power for transmission of the random access preamble (Msg1 1012) compared to other uplink transmissions (e.g., via PUSCH). The PRACH transmit power parameter message 1026 may be transmitted (e.g., broadcast) by the access point 110 and received by the access terminal 120 semi-statically, such as through MIB signaling, SIB signaling, and so on. By separating the PRACH transmit power parameter message 1026 from other transmit power limit messages, the random access preamble (Msg1 1012) can be made to conform to applicable power spectral density limits without impacting the transmission power of other messages such as the RRC request (Msg3 1016).

[0080] Conventionally, the Random Access Network Temporary Identifier (RA-RNTI) used to identify the access terminal 120 during the random access procedure can be derived from the transmission timing in the random access preamble (Msg1 1012) and the location in the frequency domain. In legacy LTE, for example, the RA-RNTI is a 16-bit value that is computed according to the following equation: RA-RNTI = 1 + t_id + 10 * f_id (Eq. 1) In this document, t_id is the index of the first subframe of the specified PRACH (0 < t_id < 10) and f_id is the index of the specified PRACH within such subframe, in ascending order of frequency domain (0 < f_id < 6).

[0081] To improve the definition of RA-RNTI to better suit the broadband (RB-interlaced) waveform of the PRACH described in this document and the option of transmission in a special subframe (in which typically only one special subframe is used in a given radio frame, so that the subframe index may not be meaningfully discernible), RA-RNTI can instead be defined as the function of the subframe index, the RB interlacing, the period index of PRACH starting symbol (e.g., symbol 1 or symbol 3 in a 4-symbol PRACH region) and/or the DMRS sequence (or associated cyclic shift or some other associated identifier) used. As an example, the modified RA-RNTI can be computed according to the following equation: RA-RNTI = 1 + k * Interlace_id + m * DMRS_seq_ID (Eq. 2)

[0082] In this document, the Interlace_id corresponds to the RB interlace used by the access terminal 120, the DMRS_seq_ID corresponds to the DMRS sequence used by the access terminal 120, and k and m are constants that can be used to separate variables and expand or shrink the RA-RNTI space as necessary.

[0083] Referring again to Figure 10, the RRC request (Msg3 1016) is conventionally retransmitted according to a Hybrid Automatic Retry Request (HARQ) retransmission scheme. However, the HARQ procedure typically relies on a separate Physical Hybrid ARQ Indicator Channel (PHICH) to transmit acknowledgment messages that may not be available within the frame structure employed by the primary RAT system 100 due to the shared nature of the medium. communication block 140. Instead, the access terminal 120 can be configured to control the retransmission of the RRC request (Msg3 1016) in different ways (retransmission control block (RE-TX) 1028). As an example, the access terminal 120 may be configured only for single transmission of the RRC request (Msg3 1016), the failure of which will trigger a retry of the random access procedure. As another example, access terminal 120 may be configured for autonomous retransmission (e.g., if the CR message (Msg4 1018) is not received within a certain time window). To avoid collision, the access point 110 may avoid, for a period of time, reallocating the uplink resources assigned for the RRC request (Msg3 1016) to any other access terminals or for any other purposes (e.g. , until the expiration of the same time window). As shown, the access point 110 may enable autonomous retransmission and any associated parameters via a configuration message or the like (relay configuration message (RE-TX) 1030). The relay configuration message 1030 may be transmitted (e.g., broadcast) by the access point 110 and received by the access terminal 120 semi-statically, such as through MIB signaling, SIB signaling, among others. As another example, the HARQ of Msg3 can be controlled by the access point 110 through retransmission of Msg2. For example, when the access point 110 does not receive Msg3 in the designated uplink subframe or within a certain time window from the time the grant was transmitted, it retransmits Msg2. After transmission of Msg3, the access terminal 120 continues to search for the PDCCH with the RA-RNTI expected to decode any retransmitted Msg2. Upon receipt of Msg2, access terminal 120 may retransmit Msg3 and reset the dispute resolution timer.

[0084] In some implementations, to increase the reliability of receiving Msg3, the access point 110 may provide multiple uplink grants (i.e., send Msg2 in multiple subframes). The access terminal 120 may transmit different cases of Msg3 in these uplink subframes using different redundancy versions, wherein the redundancy version to be used in different subframes is transmitted in the corresponding Msg2 payload (e.g., by defining whether new fields in Msg2 or redefining existing fields for this purpose).

[0085] Figure 11 is a flowchart illustrating an exemplary method of communication in accordance with the techniques described above. The method 1100 may be performed, for example, by an access terminal (e.g., the access terminal 120 illustrated in Figure 1) that operates on a shared communication medium. As an example, the communication medium may include one or more time, frequency, or space resources in an unlicensed radio frequency band shared between LTE technology and Wi-Fi technology devices.

[0086] As shown, the access terminal may receive a broadcast message that includes information associated with a PRACH in one or more subframes in a portion configured for downlink signaling. The broadcast message may comprise a race type indicator, a timing advance indicator, or a combination thereof. The access terminal can then determine whether the contention is effective for transmission on the PRACH based on the contention type indicator, whether an uplink transmission offset is effective for transmission on the PRACH based on the contention advance indicator. timing, or a combination thereof (block 1104). Based on the determination, the access terminal may transmit signaling through the PRACH in one or more subframes in a portion configured for uplink signaling (block 1106).

[0087] As discussed in greater detail above, transmission may comprise, for example, selectively competing for access to a communication medium for signaling based on determination regarding the dispute type indicator. Additionally or alternatively, the transmission may comprise, for example, transmitting the signaling at a modified initial time with respect to a subframe boundary based on the determination with respect to the timing advance indicator.

[0088] In some designs or scenarios, the PRACH may correspond to (i) a long PRACH format that occupies substantially all of the symbol periods associated with a given subframe or (ii) a short PRACH format that occupies a subset of fewer than all symbol periods associated with a given subframe. The broadcast message may also further comprise a CCA threshold indicator, a CCA duration indicator, or a combination thereof.

[0089] As an example, the uplink portion in which signaling is transmitted may be located at the end of a subframe configured for PRACH transmission, wherein the access terminal does not determine whether the subframe configured for PRACH transmission corresponds to an uplink subframe type, a downlink subframe type, or a special subframe type. As another example, the uplink portion in which the signaling is transmitted may also be located at the beginning of a subframe configured for PRACH transmission, where the access terminal again does not determine whether the subframe configured for PRACH transmission corresponds to a uplink subframe type, a downlink subframe type, or a special subframe type. It will be noted that because the access point may configure periodic PRACH opportunities and inform the access terminal of these opportunities, it may not be necessary for the access terminal to determine the type of an associated subframe to perform transmission of PRACH, which can be particularly useful for floating TDD frame structures as described above where the subframe type can be dynamically configured. The PRACH may comprise, for example, one or more RBs across one or more symbol periods that are reserved for opportunistic transmission following a blocked transmission opportunity.

[0090] In some designs or scenarios, the access terminal may also receive a duration/format indicator, an interleaving indicator, a sequence indicator, a PRACH duration/location indicator, or a combination thereof in the broadcast message. or in a separate broadcast message. The access terminal may also transmit, for a second symbol within the PRACH or for a second PRACH attempt, a random access preamble from an allocated set of DMRS sequences, the random access preamble corresponding to a second sequence of DMRS that is (i) identical to a first DMRS sequence, (ii) completely different from the first DMRS sequence, or (iii) a cyclically displaced version of the first DMRS sequence. The access terminal may also receive a PRACH-specific maximum transmit power parameter for a narrowband PRACH waveform that defines a different maximum transmit power than a PUSCH. The access terminal may also transmit a RA-RNTI that is a function of a subframe index, an RB interleave, a DMRS sequence employed for the PRACH, or a combination thereof. The access terminal may also configure itself for one-time transmission or autonomous retransmission of an RRC request message as part of a random access procedure.

[0091] Figure 12 is a flowchart illustrating another exemplary method of communication in accordance with the techniques described above. The method 1200 may be performed, for example, by an access point (e.g., the access point 110 illustrated in Figure 1) that operates on a shared communication medium. As an example, the communication medium may include one or more time, frequency, or space resources in an unlicensed radio frequency band shared between LTE technology and Wi-Fi technology devices.

[0092] As shown, the access point may define a contention type indicator to indicate whether the contention is effective for transmission on a PRACH, a timing advance indicator to indicate whether an uplink transmission offset is effective for transmission on PRACH or a combination thereof (block 1202). The access point may then transmit a broadcast message associated with the PRACH in one or more subframes in a portion configured for downlink signaling (block 1204). The broadcast message may comprise the race type indicator, the timing advance indicator, or a combination thereof. The access point may receive signaling through the PRACH in one or more subframes in a portion configured for uplink signaling (block 1206).

[0093] As discussed in greater detail above, PRACH may correspond to (i) a long PRACH format that occupies substantially all of the symbol periods associated with a given subframe or (ii) a short PRACH format that occupies a subset of less than all symbol periods associated with a given subframe. The broadcast message may also further comprise a CCA threshold indicator, a CCA duration indicator, or a combination thereof.

[0094] The uplink portion in which signaling is received may be located at the end of a special subframe following a downlink portion and a gap portion of the special subframe, wherein the special subframe is located at a transition boundary from downlink to uplink within a TDD frame structure. The uplink portion in which signaling is received may also be located at the beginning of a special subframe that precedes a downlink portion and a span portion of the special subframe, wherein the special subframe is located at a transition boundary of uplink to downlink within a TDD frame structure. The PRACH may comprise, for example, one or more RBs across one or more symbol periods that are reserved for opportunistic transmission following a blocked transmission opportunity.

[0095] In some designs or scenarios, the access point may also transmit a duration/format indicator, an interleave indicator, a sequence indicator, a PRACH duration/location indicator, or a combination thereof in the broadcast message. or in a separate broadcast message. The access point may also demodulate a random access preamble selected from an allocated set of DMRS sequences by performing RB processing and non-coherent power pooling across RBs. The access point may also transmit a PRACH-specific maximum transmit power parameter for a narrowband PRACH waveform that defines a different maximum transmit power than a PUSCH. The access point may also receive a RA-RNTI that is a function of a subframe index, an RB interleave, a DMRS sequence employed for the PRACH, or a combination thereof. The access point may also configure an access terminal for one-time transmission or autonomous retransmission of an RRC request message as part of a random access procedure.

[0096] For generality, the access point 110 and the access terminal 120 are shown in Figure 1 only in relevant part including the random access channel manager 112 and the random access channel manager 122, respectively. It will be noted, however, that the access point 110 and the access terminal 120 may be configured in various ways to provide or otherwise support the random access signaling techniques discussed herein.

[0097] Figure 13 is a device-level diagram illustrating exemplary components of the access point 110 and the access terminal 120 of the primary RAT system 100 in greater detail. As shown, the access point 110 and the access terminal 120 may each generally include a wireless communication device (represented by communication devices 1330 and 1350) for communicating with other wireless nodes via at least a designated RAT. Communication devices 1330 and 1350 can be variously configured to transmit and encode signals and, in return, to receive and decode signals according to the designated RAT (e.g., messages, indications, information, pilots, among others).

[0098] Communication devices 1330 and 1350 may include, for example, one or more transceivers, such as respective primary RAT transceivers 1332 and 1352 and, in some designs, (optional) co-located secondary RAT transceivers 1334 and 1354, respectively ( corresponding, for example, to the RAT employed by the competing RAT system 150). As used herein, a "transceiver" may include a transmitter circuit, a receiver circuit, or a combination thereof, but need not provide both transmit and receive functionality in all designs. For example, a low-functionality receiver circuit may be employed in some designs to reduce costs when providing full communication is not necessary (e.g., a radio chip or similar circuitry that provides only low-level detection ). Additionally, as used herein, the term "co-located" (e.g., radios, access points, transceivers, etc.) may refer to one of several arrangements. For example, components that are in the same housing; components that are hosted by the same processor; components that are at a defined distance from each other; and/or components that are connected via an interface (e.g., an Ethernet switch) wherein the interface satisfies the latency requirements of any required intercomponent communication (e.g., messaging).

[0099] The access point 110 and the access terminal 120 may also each generally include a communication controller (represented by communication controllers 1340 and 1360) to control the operation of their respective communication devices 1330 and 1350 (e.g. direct, modify, enable, disable, etc.). Communication controllers 1340 and 1360 may include one or more processors 1342 and 1362 and one or more memories 1344 and 1364 coupled to processors 1342 and 1362, respectively. The memories 1344 and 1364 may be configured to store data, instructions, or a combination thereof, either as an onboard cache memory, as separate components, a combination, etc. The processors 1342 and 1362 and the memories 1344 and 1364 may be stand-alone communication components or may be part of the respective host system functionality of the access point 110 and the access terminal 120.

[0100] It will be noted that the random access channel manager 112 and the random access channel manager 122 may be implemented in different ways. In some designs, some or all of the functionality associated therewith may be implemented by or otherwise at the direction of at least one processor (e.g., one or more of the processors 1342 and/or one or more of the processors 1362 ), at least one memory (e.g., one or more of memories 1344 and/or one or more of memories 1364), at least one transceiver (e.g., one or more of transceivers 1332 and 1334 and/or a or more of transceivers 1352 and 1354) or a combination thereof. In other projects, some or all of the functionality associated with them may be implemented as a series of interrelated functional modules.

[0101] Accordingly, it will be seen that the components in Figure 13 can be used to perform operations described above in relation to Figures 1 to 12. For example, the access terminal 120 receives, via the primary RAT transceiver 1352, a message broadcast that includes information associated with a PRACH in one or more subframes in a portion configured for downlink signaling. The broadcast message may comprise a race type indicator, a timing advance indicator, or a combination thereof. The access terminal 120 may then determine, via the processor 1362 and memory 1364, whether the race is effective for transmission in the PRACH based on the race type indicator, whether an uplink transmission offset is effective. for transmission in PRACH based on the timing advance indicator or a combination thereof. Based on the determination, the access terminal 120 may transmit, via the primary RAT transceiver 1352, signaling via the PRACH in one or more subframes in a portion configured for uplink signaling.

[0102] As another example, the access point 110 may define, through the processor 1342 and the memory 1344, a race type indicator to indicate whether the race is effective for transmission in a PRACH, a race advance indicator timing to indicate whether an uplink transmission offset is effective for transmission on the PRACH or a combination thereof. The access point 110 may then transmit, via the primary RAT transceiver 1332, a broadcast message associated with the PRACH in one or more subframes in a portion configured for downlink signaling. The broadcast message may comprise the race type indicator, the timing advance indicator, or a combination thereof. The access point 110 may receive, via the primary RAT transceiver 1332, signaling through the PRACH in one or more subframes in a portion configured for uplink signaling.

[0103] Figure 14 illustrates an exemplary apparatus for implementing the random access channel manager 122 represented as a series of interrelated functional modules. In the illustrated example, apparatus 1400 includes a receiving module 1402, a determining module 1404, and a transmitting module 1406.

[0104] The receiving module 1402 may receive a broadcast message that includes information associated with a PRACH in one or more subframes in a portion configured for downlink signaling. The broadcast message may comprise a race type indicator, a timing advance indicator, or a combination thereof. The determination module 1404 may determine whether the contention is effective for transmission on the PRACH based on the contention type indicator, whether an uplink transmission offset is effective for transmission on the PRACH based on the timing advance indicator, or a combination thereof. Based on the determination, the transmission module 1406 may transmit signaling via the PRACH in one or more subframes in a portion configured for uplink signaling.

[0105] Figure 15 illustrates an exemplary apparatus for implementing the random access channel manager 112 represented as a series of interrelated functional modules. In the illustrated example, apparatus 1500 includes a definition module 1502, a transmission module 1504, and a receive module 1506.

[0106] The definition module 1502 may define a race type indicator to indicate whether the race is effective for transmission on a PRACH, a timing advance indicator to indicate whether an uplink transmission offset is effective for the transmission in PRACH or a combination thereof. The transmission module 1504 may transmit a broadcast message associated with the PRACH in one or more subframes in a portion configured for downlink signaling. The broadcast message may comprise the race type indicator, the timing advance indicator, or a combination thereof. The receiving module 1506 may receive signaling via the PRACH in one or more subframes in a portion configured for uplink signaling.

[0107] The functionality of the modules of Figures 14 to 15 can be implemented in various ways consistent with the teachings herein. In some designs, the functionality of these modules may be implemented as one or more electrical components. In some designs, the functionality of these blocks may be implemented as a processing system that includes one or more processor components. In some designs, the functionality of these modules may be implemented using, for example, at least a portion of one or more integrated circuits (e.g., an ASIC). As discussed herein, an integrated circuit may include a processor, software, other related components, or some combination thereof. Therefore, the functionality of different modules can be implemented, for example, as different subsets of an integrated circuit, as different subsets of a set of software modules, or a combination thereof. Furthermore, it will be appreciated that a given subset (e.g., of an integrated circuit and/or a set of software modules) may provide at least a portion of the functionality for more than one module.

[0108] Additionally, the components and functions represented by Figures 14 to 15, as well as other components and functions described in this document, can be implemented using any suitable means. Such means can also be implemented, at least in part, with the use of corresponding structure as taught herein. For example, the components described above in conjunction with the "module for" components of Figures 14 to 15 may also correspond to similarly designated "means for" functionality. Therefore, in some aspects, one or more of such means may be implemented using one or more of the processor components, integrated circuits or other suitable structure as taught herein, including an algorithm. One skilled in the art will recognize in the present disclosure an algorithm represented in the prose described above, as well as in sequences of actions that can be represented by pseudocode. For example, the components and functions represented by Figures 14 to 15 may include code to perform a LOAD operation, a COMPARISON operation, a RETURN operation, an IF-THEN-ELSE cycle, among others.

[0109] It should be understood that any reference to an element in this document using a designation such as "first", "second", among others, does not generally limit the quantity or order of such elements. Instead, these designations may be used herein as a convenient method for distinguishing between two or more elements or occurrences of an element. Thus, a reference to the first and second elements does not mean that only two elements can be used there, or that the first element must precede the second element in some way. Furthermore, unless otherwise stated, a set of elements may comprise one or more elements. Additionally, terminology of the form "at least one of A, B or C" or "one or more of A, B or C" or "at least one of the group consisting of A, B and C" used in the description or claims means "A or B or C or any combination thereof." For example, this terminology may include A or B or C, or A and B, or A and C, or A and B and C, or 2A or 2B or 2C among others.

[0110] In view of the above descriptions and explanations, one skilled in the art will appreciate that the various illustrative logic blocks, modules, circuits and algorithm steps described in connection with the aspects disclosed herein can be implemented as electronic hardware, software computer or combinations of both. To clearly illustrate this interchangeability of hardware and software, several illustrative components, blocks, modules, circuits and steps have been described above generally in terms of their functionality. Whether such functionality can be implemented as hardware or as software depends on the particular application and the design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in varying ways for each particular application, however, such implementation decisions should not be interpreted so as to cause a departure from the scope of the present disclosure.

[0111] Accordingly, it will be seen, for example, that an apparatus or any component of an apparatus may be configured to (or operatively produced for or adapted to) provide functionality as taught herein. This can be achieved, for example: by producing (e.g. manufacturing) the device or component so that it provides the functionality; programming the device or component so that it provides the functionality; or through the use of some other suitable implementation technique. As an example, an integrated circuit can be manufactured to provide the required functionality. As another example, an integrated circuit may be manufactured to support required functionality and then configured (e.g., programmatically) to provide the required functionality. As yet another example, a processor circuit may execute code to provide necessary functionality.

[0112] Furthermore, the methods, sequences and/or algorithms described in relation to the aspects disclosed in this document can be incorporated directly into hardware, into a software module executed by a processor or in a combination of the two. A software module may be situated in Random Access Memory (RAM), flash memory, Read Only Memory (ROM), Erasable Programmable Read Only Memory (EPROM), Electrically Erasable Programmable Read Only Memory (EEPROM), registers, hard disk, a removable disk, a CD-ROM or any other form of storage medium known in the art, transient or non-transitory. An exemplary storage medium is coupled to the processor so that the processor can read information from, and write information to, the storage medium. Alternatively, the storage medium may be an integral part of the processor (e.g., cache memory).

[0113] Accordingly, it will also be noted, for example, that certain aspects of the disclosure may include a non-transitional or transitional computer-readable medium that incorporates a method for communication.

[0114] Although the aforementioned disclosure shows several illustrative aspects, it should be noted that various changes and modifications can be made to the illustrated examples without departing from the scope defined by the attached claims. The present disclosure is not intended to be limited to the specifically illustrated examples alone. For example, unless otherwise noted, the functions, steps and/or actions of the method claims in accordance with aspects of the disclosure described herein need not be performed in any particular order. Furthermore, although certain aspects may be described or claimed in the singular, the plural is contemplated, unless the limitation to the singular is explicitly indicated.

Claims (16)

1. Method of communication (1100) in an access terminal characterized by the fact that it comprises: receiving (1102) a broadcast message that includes information associated with a Physical Random Access Channel (PRACH) in one or more subframes in a portion configured for downlink signaling, wherein the broadcast message comprises a race type indicator, a timing advance indicator, or a combination thereof, wherein the race type indicator indicates one of: that no race is active , that a contest without random back-off is active, that a contest with random back-off having a fixed-size contest window is active, that a contest with random back-off having a variable-size contest window is active; determine (1104) whether and to what extent the race is active for transmission on the PRACH based on the race type indicator, whether an uplink transmission offset is active for transmission on the PRACH based on the timing advance indicator, or a combination of these; transmit (1106) signaling through the PRACH in one or more subframes in a portion configured for determination-based uplink signaling, wherein the transmission comprises selectively contesting access to a communication medium for determination-based signaling with respect to to the dispute type indicator; and receiving a PRACH-specific maximum transmit power parameter for a narrowband PRACH waveform that defines a different maximum transmit power for a Physical Uplink Shared Channel (PUSCH). 2. Method according to claim 1, characterized by the fact that the transmission is carried out at a modified initial time with respect to a subframe limit based on the determination with respect to the timing advance indicator. 3. Method according to claim 1, characterized by the fact that the PRACH corresponds to one of: a long PRACH format that occupies all symbol periods associated with a given subframe or a short PRACH format that occupies a subset of less than all symbol periods associated with a given subframe. 4. The method of claim 1, wherein the broadcast message further comprises a Channel Clear Assessment (CCA) threshold indicator, a CCA duration indicator, or a combination thereof. 5. Method according to claim 1, characterized by the fact that the uplink portion in which the signaling is transmitted is located at the end of a subframe configured for PRACH transmission, and in which the transmission is carried out without determining whether The subframe configured for PRACH transmission corresponds to an uplink subframe type, a downlink subframe type, or a special subframe type. 6. Method according to claim 1, characterized by the fact that the uplink portion in which the signaling is transmitted is located at the beginning of a subframe configured for PRACH transmission, and in which the transmission is carried out without determining whether The subframe configured for PRACH transmission corresponds to an uplink subframe type, a downlink subframe type, or a special subframe type. 7. Method according to claim 1, characterized by the fact that it further comprises receiving a duration/format indicator, an interleaving indicator, a sequence indicator, a PRACH duration/location indicator or a combination thereof in the message broadcast message or in a separate broadcast message. 8. The method of claim 1, wherein the PRACH comprises one or more Resource Blocks (RBs) across one or more symbol periods that are reserved for opportunistic transmission following a blocked transmission opportunity. 9. The method of claim 1, further comprising transmitting, for a second symbol within the PRACH or for a second PRACH attempt, a random access preamble from an allocated set of Signal sequences Demodulation Reference System (DMRS), the random access preamble corresponding to a second DMRS sequence that is one of: identical to a first DMRS sequence, completely different from the first DMRS sequence, or a cyclically shifted version of the first DMRS sequence DMRS. 10. The method of claim 1, further comprising transmitting a Random Access Network Temporary Identifier (RA-RNTI) which is a function of a subframe index, a Resource Block interleaving (RB ), a Demodulation Reference Signal sequence (DMRS) employed for the PRACH, or a combination thereof. 11. The method of claim 1, further comprising configuring the access terminal for single transmission or autonomous retransmission of a Radio Resource Control (RRC) request message as part of an access procedure random. 12. Communication apparatus (1400) characterized by the fact that it comprises: means (1402) configured to receive a broadcast message that includes information associated with a Physical Random Access Channel (PRACH) in one or more subframes in a portion configured to downlink signaling, wherein the broadcast message comprises a race type indicator, a timing advance indicator, or a combination thereof, wherein the race type indicator indicates one of: that no race is active, that a contest without random back-off is active, that a contest with random back-off having a fixed-size contest window is active, that a contest with random back-off having a variable-size contest window is active; means (1404) configured to determine whether and to what extent the race is active for transmission on the PRACH based on the race type indicator, whether an uplink transmission offset is active for transmission on the PRACH based on the race advance indicator timing, or a combination of these; means (1406) configured to transmit signaling through the PRACH in one or more subframes in a portion configured for uplink signaling based on determination, wherein the transmission comprises selectively contesting access to a communication medium for signaling based on the determination regarding the dispute type indicator; and means configured to receive a PRACH-specific maximum transmit power parameter for a narrowband PRACH waveform that defines a different maximum transmit power from a Physical Uplink Shared Channel (PUSCH). 13. Computer-readable memory characterized by the fact that it contains instructions stored therein that, when executed, cause a computer to perform the method as defined in any one of claims 1 to 11. 14. Method of communicating (1200) at an access point characterized by the fact that it comprises: defining (1202) a contention type indicator to indicate whether the contention is active for transmission on a Physical Random Access Channel (PRACH), a timing advance indicator to indicate whether an uplink transmission offset is active for transmission on the PRACH, or a combination thereof, wherein the race type indicator indicates one of: that no race is active, that a race with no back -random off is active, that a contest with random back-off having a fixed-size contest window is active, that a contest with random back-off having a variable-size contest window is active; transmit (1204) a broadcast message that includes information associated with the PRACH in one or more subframes in a portion configured for downlink signaling, wherein the broadcast message comprises the race type indicator, the timing advance indicator or a combination of these; receiving (1206) signaling via the PRACH in one or more subframes in a portion configured for uplink signaling; and transmitting a PRACH-specific maximum transmit power parameter to a narrowband PRACH waveform that defines a different maximum transmit power of a Physical Uplink Shared Channel (PUSCH). 15. Communication apparatus (1500) characterized by the fact that it comprises: means (1502) configured to define a contest type indicator to indicate whether the contest is active for transmission on a Physical Random Access Channel (PRACH), an indicator of timing advance to indicate whether an uplink transmission offset is active for transmission on the PRACH or a combination thereof, wherein the race type indicator indicates one of: that no race is active, that a race with no back-off random is active, that a contest with random back-off having a fixed-size contest window is active, that a contest with random back-off having a variable-size contest window is active; means (1504) configured to transmit a broadcast message associated with the PRACH in one or more subframes in a portion configured for downlink signaling, wherein the broadcast message comprises the race type indicator, the timing advance indicator or a combination of these; means (1506) configured to receive signaling through the PRACH in one or more subframes in a portion configured for uplink signaling; and means configured to transmit a PRACH-specific maximum transmit power parameter for a narrowband PRACH waveform that defines a different maximum transmit power than a Physical Uplink Shared Channel (PUSCH). 16. Computer-readable memory characterized by the fact that it contains instructions stored therein that, when executed, cause a computer to perform the method as defined in claim 14.