WO2017196459A1

WO2017196459A1 - Rach-less handover to small cell

Info

Publication number: WO2017196459A1
Application number: PCT/US2017/025617
Authority: WO
Inventors: Candy YIU; Seunghee Han; Yujian Zhang; Yang Tang
Original assignee: Intel IP Corporation
Priority date: 2016-05-13
Filing date: 2017-03-31
Publication date: 2017-11-16
Also published as: DE112017002452T5

Abstract

Briefly, in accordance with one or more embodiments, an apparatus of an evolved Node B (eNB) comprises one or more baseband processors to process a handover request received from a source eNB for a user equipment (UE) connected with the source eNB, and a memory to store handover request information. The one or more baseband processors are to encode a mobility control information element MobilityControlInfo with an indication regarding a random-access channel (RACH) procedure for a handover of the UE from the source eNB

Description

RACH-LESS HANDOVER TO SMALL CELL

CROSS-REFERENCE TO RELATED APPLICATIONS The present application claims the benefit of US Provisional Application No. 62/335,925 (P98852Z) filed May 13, 2016. Said Application No. 62/335,925 is hereby incorporated herein by reference in its entirety.

BACKGROUND

The solution of RACH-less handover can be introduced when the source cell, the target cell and the UE are synchronized. In a synchronized network, it is assumed that subframe boundary between the source cell and target cell are aligned. One option is that at a mutually agreed time (e.g. SFN), the UE switches from source cell to target cell, without requiring random access procedure. Another option is that the UE follows the legacy handover procedure but skips the RACH related steps. A RACH attempt procedure during handovers typically takes—10—12 ms. An average handover procedure takes -40-50 ms to complete. Eliminating -10-12 ms of RACH delay during a handover procedure can significantly reduce the data interruption during handovers and improve the user experience.

The synchronization may be achieved between the two eNB cells over X2 signaling and the UE via RRC signaling. Based on the fact that all three nodes are in sync, the source cell stops DL transmission to the UE, the target cell provides an uplink grant to the UE, and the UE acquires the target.

DESCRIPTION OF THE DRAWING FIGURES

Claimed subject matter is particularly pointed out and distinctly claimed in the concluding portion of the specification. However, such subject matter may be understood by reference to the following detailed description when read with the accompanying drawings in which:

FIG. 1 is a diagram of a RACH-less handover procedure wherein a timing advance for a target cell is approximately equal to zero in accordance with one or more embodiments;

FIG. 2 is a diagram of a RACH-less handover procedure using a MobilityControlInfo information element in accordance with one or more embodiments;

FIG. 3 is a block diagram of an information handling system capable of implementing mobility measurements for beamforming in accordance with one or more embodiments;

FIG. 4 is an isometric view of an information handling system of FIG. 4 that optionally may include a touch screen in accordance with one or more embodiments; and FIG. 5 is a diagram of example components of a wireless device in accordance with one or more embodiments.

It will be appreciated that for simplicity and/or clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, if considered appropriate, reference numerals have been repeated among the figures to indicate corresponding and/or analogous elements.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are set forth to provide a thorough understanding of claimed subject matter. It will, however, be understood by those skilled in the art that claimed subject matter may be practiced without these specific details. In other instances, well-known methods, procedures, components and/or circuits have not been described in detail.

In the following description and/or claims, the terms coupled and/or connected, along with their derivatives, may be used. In particular embodiments, connected may be used to indicate that two or more elements are in direct physical and/or electrical contact with each other. Coupled may mean that two or more elements are in direct physical and/or electrical contact. However, coupled may also mean that two or more elements may not be in direct contact with each other, but yet may still cooperate and/or interact with each other. For example, "coupled" may mean that two or more elements do not contact each other but are indirectly joined together via another element or intermediate elements. Finally, the terms "on," "overlying," and "over" may be used in the following description and claims. "On," "overlying," and "over" may be used to indicate that two or more elements are in direct physical contact with each other. It should be noted, however, that "over" may also mean that two or more elements are not in direct contact with each other. For example, "over" may mean that one element is above another element but not contact each other and may have another element or elements in between the two elements. Furthermore, the term "and/or" may mean "and", it may mean "or", it may mean "exclusive-or", it may mean "one", it may mean "some, but not all", it may mean "neither", and/or it may mean "both", although the scope of claimed subject matter is not limited in this respect. In the following description and/or claims, the terms "comprise" and "include," along with their derivatives, may be used and are intended as synonyms for each other.

Referring now to FIG. 1, a diagram of a RACH-less handover procedure wherein a timing advance for a target cell is approximately equal to zero in accordance with one or more embodiments will be discussed. During a handover from a source cell or source evolved Node B (eNB) 110 to a target cell or target eNB 112, the random access channel (RACH) procedure is utilized to obtain a timing advance (TA) value for the target eNB 112. In the absence of the RACH procedure, referred to as a RACH-less handover or a RACH-skip, user equipment (UE) 114 may be able to obtain the TA value for the target eNB 112 without an explicit TA command if the source eNB 110 and the target eNB 112 are time synchronized. As shown in FIG. 1, UE 114 may obtain the difference in downlink (DL) propagation delays between the source eNB 110, having a propagation delay Tl, and the target eNB 112, having a propagation delay T2. The DL propagation delay difference is T1-T2. If it is assumed that the uplink (UL) propagation delay is the same as the DL propagation delay, UE 114 may derive the TA value for the target eNB 112 from the TA value of the source eNB 110 as follows:

TAtarget = TAsource - 2(T1 - T2)

Another purpose of the RACH procedure during handover is to obtain an UL grant for the transmission of the handover command response, the radio resource control (RRC) Connection Reconfiguration Complete message. In the absence of the RACH procedure for the target eNB 112, allocation of the UL grant is needed in the target eNB 112. One option is to utilize a UL grant pre-allocation in handover command. The pre-allocated UL grant may be kept valid within a period of time, starting from the time when UE 114 achieves synchronization with the target eNB 112. Another option is to utilize a UL grant allocation by dynamic scheduling in the target eNB 112. The target eNB112 may allocate an UL grant to UE 114 by dynamic scheduling from the time when target eNB 112 expects UE 114 to be available for scheduling, for example based on mutually agreed time, or sometime later after the handover preparation procedure which is subject to implementation by the target eNB 112. The initial value of physical uplink shared channel (PUSCH) transmission power control may be based on physical random access channel (PRACH) preamble power and total power ramp. If the PRACH procedure is removed, power control in the PUSCH may be modified.

In one or more embodiments as discussed herein, a RACH-less procedure may involve obtaining a TA value for the target eNB 112, power ramping, and an UL grant. In order for UE 114 to obtain a TA value from the target eNB 112, the TA value may be obtained from either a calculation performed by UE 114 or from a calculation performed by the network such as by the source eNB 110 or the target eNB 112. In one or more embodiments, it may be possible to skip the RACH procedure for handover to small cell which has a small radius, for example less than about 240 meters, although the scope of the claimed subject matter is not limited in this respect. In such a situation, UE 114 may utilize a timing advance value of zero (TA = 0, configured by the network) for the target eNB 112. Thus, in accordance with one or more embodiments, a RACH-less handover may be applied in a handover from a macro cell to a small cell, wherein the source eNB 110 is a macro cell and the target eNB 112 is a small cell. In accordance with one or more alternative embodiments, a RACH-less handover may be applied in a handover from a small cell to a small cell, wherein the source eNB 110 is a small cell and the target eNB 112 is a small cell. A macro cell may refer to a cell in a cellular network that generally may provide a higher power cellular base station, typically the highest power base station on the network with an output power on the order of tens of watts. A small cell may refer to a radio access node of a network that may operate on the network with a lower output power and range that is less than the power of the higher power macro cell and which may include, for example, femtocells, picocells, and/or microcells, although the scope of the claimed subject matter is not limited in this respect. Options for providing knowledge to UE 114 to know if a RACH-less handover may be utilized are shown in and described with respect to FIG. 2, below.

Referring now to FIG. 2, a diagram of a RACH-less handover procedure using a MobilityControlInfo information element in accordance with one or more embodiments will be discussed. As shown in FIG. 2, UE 114 may perform a handover from source eNB 110 using link 116 to target eNB 112 using link 118. UE 114 may know whether or not a RACH-less handover (HO), or a RACH-skip, may be utilized as follows. In one embodiment, after UE 114 obtains a measurement report for the target eNB 112, UE 114 sends the measurement report to the source eNB 110. The source eNB 110 then may decide whether or not to handover UE 114 to the target eNB 112. If the target eNB 112 is a small cell, then the target eNB 110 may decide to apply a RACH-less handover when receive HO request from source eNB. The decision to apply a RACH-less handover may be indicated in the handover command sent to UE 114 from the source eNB 110 (but the information for mobility is generated by target eNB), for example in the mobility control information element (IE) MobilityControlInfo (generated by target eNB) that is sent with the RRC Connection Reconfiguration message RRCConnectionReconflguration in the handover command in accordance with the Third Generation Partnership Project (3GPP) Technical Standard (TS) 36.331 shown below. The mobility control IE MobilityControlInfo includes parameters relevant for network controlled mobility to and/or within the Evolved Universal Terrestrial Radio Access (E-UTRA). The modification to the mobility control information element (IE) MobilityControlInfo providing the indication to apply a RACH-less handover to a small is shown in underlining, below.

MobilityControlInfo Information Element

ASM STA RT

In another embodiment, the network may indicate to UE 114 that the target eNB 112 is a small cell, and UE 114 may then decide itself if UE 1 14 wants to perform a RACH-less handover or not. In such an arrangement, the modification to the mobility control information element (IE) Mobility 'Controllnfo providing the indication to UE 114 that the target eNB 112 is a small cell is shown in underlining, below.

MobilityControlInfo information element

ASN I STA RT

For Power ramping, UE 114 may utilize the pathloss as an estimation for initial access to the target eNB 112.

In accordance with one or more embodiments, a handover (HO) of UE 114 from source eNB 110 to target eNB 112 may be implemented in compliance with a 3GPP Technical Standard (TS), for example as described in Section 5.3.1.3 "Connected mod mobility" of 3GPP TS 36.331 Release 14, although the scope of the claimed subject matter is not limited in this respect. In such an arrangement, in RRC CONNECTED, the network controls UE 114 mobility, i.e. the network decides when the UE 114 shall connect to which Evolved Universal Terrestrial Radio Access (E-UTRA) cell(s), or inter Radio Access Technology (inter-RAT) cell. For network controlled mobility in RRC CONNECTED, the Primary Cell (PCell) can be changed using an RRCConnectionReconfiguration message including the mobilityControlInfo (handover), whereas the Secondary Cell or Cells (SCell(s)) can be changed using the RRCConnectionReconfiguration message either with or without the mobilityControlInfo.

An SCG can be established, reconfigured or released by using an RRCConnectionReconfiguration message with or without the mobilityControlInfo. In case Random Access to the PSCell or initial PUSCH to the PSCell if rach-SkipSCG is configured is required upon Secondary Cell Group (SCG) reconfiguration, E-UTRAN employs the SCG change procedure (i.e. an RRCConnectionReconfiguration message including the mobihtyControlInfoSCG). The Primary SCell (PSCell) can only be changed using the SCG change procedure and by release and addition of the PSCell.

The network triggers the handover procedure, for example based on radio conditions, load. To facilitate this, the network may configure the UE 114 to perform measurement reporting (possibly including the configuration of measurement gaps). The network may also initiate handover blindly, that is without having received measurement reports from the UE 114.

Before sending the handover message to the UE 114, the source eNB 110 prepares one or more target cells. The source eNB 110 selects the target PCell. The source eNB 110 may also provide the target eNB 112 with a list of best cells on each frequency for which measurement information is available, in order of decreasing Reference Signal Received Power (RSRP). The source eNB 110 may also include available measurement information for the cells provided in the list. The target eNB 112 decides which SCells are configured for use after handover, which may include cells other than the ones indicated by the source eNB. If an SCG is configured, handover involves either SCG release or SCG change. In case the UE 114 was configured with Downlink Control (DC), the target eNB 112 indicates in the handover message whether the UE 114 shall release the entire SCG configuration. Upon connection re-establishment, the UE 114 releases the entire SCG configuration except for the Data Radio Bearer (DRB) configuration, while E-UTRAN in the first reconfiguration message following the re-establishment either releases the DRB(s) or reconfigures the DRB(s) to Master Cell Group (MCG) DRB(s).

The target eNB 112 generates the message used to perform the handover, i.e. the message including the Access Stratum configuration )AS-configuration) to be used in the target cell(s). The source eNB 110 transparently (i.e. does not alter values/ content) forwards the handover message/ information received from the target to the UE. When appropriate, the source eNB 110 may initiate data forwarding for (a subset of) the DRBs.

After receiving the handover message, the UE 114 attempts to access the target PCell at the first available RACH occasion according to Random Access resource selection defined in 3 GPP TS 36.321, i.e. the handover is asynchronous, or at the first available Physical Uplink Control Channel (PUSCH) occasion if RACH-Skip is configured. Consequently, when allocating a dedicated preamble for the random access in the target PCell, E-UTRA shall ensure it is available from the first RACH occasion the UE 114 may use. Upon successful completion of the handover, the UE 114 sends a message used to confirm the handover.

If the target eNB 112 does not support the release of Radio Resource Control (RRC) protocol which the source eNB 110 used to configure the UE 114, the target eNB 112 may be unable to comprehend the UE 114 configuration provided by the source eNB 110. In this case, the target eNB 112 should use the full configuration option to reconfigure the UE 114 for Handover and Re-establishment. Full configuration option includes an initialization of the radio configuration, which makes the procedure independent of the configuration used in the source cell(s) with the exception that the security algorithms are continued for the RRC re- establishment.

After the successful completion of handover, Packet Data Convergence Protocol (PDCP) Service Data Units (SDUs) may be re-transmitted in the target cell(s). This only applies for DRBs using Radio Link Control Acknowledgement Mode (RLC-AM) mode and for handovers not involving full configuration option. The further details are specified in 3GPP TS 36.323. After the successful completion of handover not involving full configuration option, the Sequence Number (SN) and the Hyper Frame Number (HFN) are reset except for the DRBs using RLC-AM mode (for which both SN and HFN continue). For reconfigurations involving the full configuration option, the PDCP entities are newly established (SN and HFN do not continue) for all DRBs irrespective of the RLC mode. The further details are specified in 3GPP TS 36.323.

One UE 114 behavior to be performed upon handover is specified, i.e. this is regardless of the handover procedures used within the network (e.g. whether the handover includes X2 or SI signaling procedures). The source eNB 110 should, for some time, maintain a context to enable the UE 114 to return in case of handover failure. After having detected handover failure, the UE 114 attempts to resume the RRC connection either in the source PCell or in another cell using the RRC re-establishment procedure. This connection resumption succeeds only if the accessed cell is prepared, i.e. concerns a cell of the source eNB 110 or of another eNB towards which handover preparation has been performed. The cell in which the re-establishment procedure succeeds becomes the PCell while SCells and Secondary Timing Advance Groups (STAGs), if configured, are released.

Normal measurement and mobility procedures are used to support handover to cells broadcasting a Closed Subscriber Group (CSG) identity. In addition, E-UTRAN may configure the UE 114 to report that it is entering or leaving the proximity of cell(s) included in its CSG whitelist. Furthermore, E-UTRAN may request the UE 114 to provide additional information broadcast by the handover candidate cell e.g. global cell identity, CSG identity, CSG membership status.

It should be noted that E-UTRAN may use the 'proximity report' to configure measurements as well as to decide whether or not to request additional information broadcast by the handover candidate cell. The additional information is used to verify whether or not the UE 114 is authorized to access the target PCell and may also be needed to identify handover candidate cell (Physical Cell Identity (PCI) confusion i.e. when the physical layer identity that is included in the measurement report does not uniquely identify the cell).

Another version of the MobilityControlInfo information element (IE) may be as follows, for example where target eNB 112 decides to configure a RACH-less handover (RACH-skip) and a timing advance (TA) value of zero, may be as follows with the RACH-skip and TA = 0 configuration being indicated via underlining.

MobilityControlInfo information element

Referring now to FIG. 3, a block diagram of an information handling system capable of implementing a RACH-less handover in accordance with one or more embodiments will be discussed. Although information handling system 300 represents one example of several types of computing platforms, information handling system 300 may include more or fewer elements and/or different arrangements of elements than shown in FIG. 3, and the scope of the claimed subject matter is not limited in these respects. In one or more embodiments, information handling system 300 may tangibly embody an apparatus of an evolved Node B (eNB) comprises one or more baseband processors to process a measurement report received from a user equipment for a target eNB to determine if the target eNB is a small cell, and a memory to store the measurement report. The one or more baseband processors are to encode a mobility control information element MobilityControlInfo with an indication regarding a random-access channel (RACH) procedure for a handover to the target eNB if the target eNB is a small cell. In one or more other embodiments, an apparatus of a user equipment (UE) comprises one or more baseband processors to encode a measurement report of a target evolved Node B (eNB) to be sent to a source eNB, and a memory to store the measurement report. The one or more baseband processors are to decode a mobility control information element MobilityControlInfo received from the source eNB, the mobility control information element including an indication regarding a random-access channel (RACH) procedure for a handover to the target eNB if the target eNB is a small cell. In one or more embodiments, information handling system 300 may include one or more applications processors 310 and one or more baseband processors 312. Applications processor 310 may be utilized as a general-purpose processor to run applications and the various subsystems for information handling system 300. Applications processor 310 may include a single core or alternatively may include multiple processing cores. One or more of the cores may comprise a digital signal processor or digital signal processing (DSP) core. Furthermore, applications processor 310 may include a graphics processor or coprocessor disposed on the same chip, or alternatively a graphics processor coupled to applications processor 310 may comprise a separate, discrete graphics chip. Applications processor 310 may include on board memory such as cache memory, and further may be coupled to external memory devices such as synchronous dynamic random access memory (SDRAM) 314 for storing and/or executing applications during operation, and NAND flash 316 for storing applications and/or data even when information handling system 300 is powered off. In one or more embodiments, instructions to operate or configure the information handling system 300 and/or any of its components or subsystems to operate in a manner as described herein may be stored on an article of manufacture comprising a non-transitory storage medium. In one or more embodiments, the storage medium may comprise any of the memory devices shown in and described herein, although the scope of the claimed subject matter is not limited in this respect. Baseband processor 312 may control the broadband radio functions for information handling system 300. Baseband processor 312 may store code for controlling such broadband radio functions in a NOR flash 318. Baseband processor 312 controls a wireless wide area network (WW AN) transceiver 320 which is used for modulating and/or demodulating broadband network signals, for example for communicating via a 3 GPP LTE or LTE-Advanced network or the like.

In general, WW AN transceiver 320 may operate according to any one or more of the following radio communication technologies and/or standards including but not limited to: a Global System for Mobile Communications (GSM) radio communication technology, a General Packet Radio Service (GPRS) radio communication technology, an Enhanced Data Rates for GSM Evolution (EDGE) radio communication technology, and/or a Third Generation Partnership Project (3GPP) radio communication technology, for example Universal Mobile Telecommunications System (UMTS), Freedom of Multimedia Access (FOMA), 3GPP Long Term Evolution (LTE), 3GPP Long Term Evolution Advanced (LTE Advanced), Code division multiple access 2000 (CDMA2000), Cellular Digital Packet Data (CDPD), Mobitex, Third Generation (3G), Circuit Switched Data (CSD), High-Speed Circuit-Switched Data (HSCSD), Universal Mobile Telecommunications System (Third Generation) (UMTS (3G)), Wideband Code Division Multiple Access (Universal Mobile Telecommunications System) (W-CDMA (UMTS)), High Speed Packet Access (HSPA), High-Speed Downlink Packet Access (HSDPA), High-Speed Uplink Packet Access (HSUPA), High Speed Packet Access Plus (HSPA+), Universal Mobile Telecommunications System-Time-Division Duplex (UMTS-TDD), Time Division-Code Division Multiple Access (TD-CDMA), Time Division-Synchronous Code Division Multiple Access (TD-CDMA), 3rd Generation Partnership Project Release 8 (Pre-4th Generation) (3 GPP Rel. 8 (Pre-4G)), 3 GPP Rel. 9 (3rd Generation Partnership Project Release 9), 3 GPP Rel. 10 (3rd Generation Partnership Project Release 10) , 3 GPP Rel. 11 (3rd Generation Partnership Project Release 11), 3GPP Rel. 12 (3rd Generation Partnership Project Release 12), 3 GPP Rel. 13 (3rd Generation Partnership Project Release 12), 3 GPP Rel. 14 (3rd Generation Partnership Project Release 12), 3GPP LTE Extra, NR (5G), LTE Licensed-Assisted Access (LAA), UMTS Terrestrial Radio Access (UTRA), Evolved UMTS Terrestrial Radio Access (E-UTRA), Long Term Evolution Advanced (4th Generation) (LTE Advanced (4G)), cdmaOne (2G), Code division multiple access 2000 (Third generation) (CDMA2000 (3G)), Evolution-Data Optimized or Evolution-Data Only (EV-DO), Advanced Mobile Phone System (1st Generation) (AMPS (1G)), Total Access Communication System/Extended Total Access Communication System (TACS/ETACS), Digital AMPS (2nd Generation) (D-AMPS (2G)), Push-to-talk (PTT), Mobile Telephone System (MTS), Improved Mobile Telephone System (IMTS), Advanced Mobile Telephone System (AMTS), OLT (Norwegian for Offentlig Landmobil Telefoni, Public Land Mobile Telephony), MTD (Swedish abbreviation for Mobiltelefonisystem D, or Mobile telephony system D), Public Automated Land Mobile (Autotel/PALM), ARP (Finnish for Autoradiopuhelin, "car radio phone"), NMT (Nordic Mobile Telephony), High capacity version of NTT (Nippon Telegraph and Telephone) (Hicap), Cellular Digital Packet Data (CDPD), Mobitex, DataTAC, Integrated Digital Enhanced Network (iDEN), Personal Digital Cellular (PDC), Circuit Switched Data (CSD), Personal Handy-phone System (PHS), Wideband Integrated Digital Enhanced Network (WiDEN), iBurst, Unlicensed Mobile Access (UMA), also referred to as also referred to as 3GPP Generic Access Network, or GAN standard), Zigbee, Bluetooth®, Wireless Gigabit Alliance (WiGig) standard, millimeter wave (mmWave) standards in general for wireless systems operating at 10-90 GHz and above such as WiGig, IEEE 802. Had, IEEE 802.1 lay, and so on, and/or general telemetry transceivers, and in general any type of RF circuit or RFI sensitive circuit. It should be noted that such standards may evolve over time, and/or new standards may be promulgated, and the scope of the claimed subject matter is not limited in this respect.

The WW AN transceiver 320 couples to one or more power amps 322 respectively coupled to one or more antennas 324 for sending and receiving radio-frequency signals via the WW AN broadband network. The baseband processor 312 also may control a wireless local area network (WLAN) transceiver 326 coupled to one or more suitable antennas 328 and which may be capable of communicating via a Wi-Fi, Bluetooth®, and/or an amplitude modulation (AM) or frequency modulation (FM) radio standard including an IEEE 802.11 a/b/g/n standard or the like. It should be noted that these are merely example implementations for applications processor 310 and baseband processor 312, and the scope of the claimed subject matter is not limited in these respects. For example, any one or more of SDRAM 314, NAND flash 316 and/or NOR flash 318 may comprise other types of memory technology such as magnetic memory, chalcogenide memory, phase change memory, or ovonic memory, and the scope of the claimed subject matter is not limited in this respect.

In one or more embodiments, applications processor 310 may drive a display 330 for displaying various information or data, and may further receive touch input from a user via a touch screen 332 for example via a finger or a stylus. An ambient light sensor 334 may be utilized to detect an amount of ambient light in which information handling system 300 is operating, for example to control a brightness or contrast value for display 330 as a function of the intensity of ambient light detected by ambient light sensor 334. One or more cameras 336 may be utilized to capture images that are processed by applications processor 310 and/or at least temporarily stored in NAND flash 316. Furthermore, applications processor may couple to a gyroscope 338, accelerometer 340, magnetometer 342, audio coder/decoder (CODEC) 344, and/or global positioning system (GPS) controller 346 coupled to an appropriate GPS antenna 348, for detection of various environmental properties including location, movement, and/or orientation of information handling system 300. Alternatively, controller 346 may comprise a Global Navigation Satellite System (GNSS) controller. Audio CODEC 444 may be coupled to one or more audio ports 350 to provide microphone input and speaker outputs either via internal devices and/or via external devices coupled to information handling system via the audio ports 350, for example via a headphone and microphone jack. In addition, applications processor 310 may couple to one or more input/output (I/O) transceivers 352 to couple to one or more I/O ports 354 such as a universal serial bus (USB) port, a high-definition multimedia interface (HDMI) port, a serial port, and so on. Furthermore, one or more of the I/O transceivers 352 may couple to one or more memory slots 356 for optional removable memory such as secure digital (SD) card or a subscriber identity module (SIM) card, although the scope of the claimed subject matter is not limited in these respects.

Referring now to FIG. 4, an isometric view of an information handling system of FIG. 3 that optionally may include a touch screen in accordance with one or more embodiments will be discussed. FIG. 4 shows an example implementation of information handling system 300 of FIG. 3 tangibly embodied as a cellular telephone, smartphone, or tablet type device or the like. The information handling system 300 may comprise a housing 410 having a display 330 which may include a touch screen 332 for receiving tactile input control and commands via a finger 416 of a user and/or a via stylus 418 to control one or more applications processors 410. The housing 410 may house one or more components of information handling system 300, for example one or more applications processors 310, one or more of SDRAM 314, NAND flash 316, NOR flash 318, baseband processor 312, and/or WW AN transceiver 320. The information handling system 300 further optionally may include a physical actuator area 420 which may comprise a keyboard or buttons for controlling information handling system via one or more buttons or switches. The information handling system 300 may also include a memory port or slot 356 for receiving nonvolatile memory such as flash memory, for example in the form of a secure digital (SD) card or a subscriber identity module (SIM) card. Optionally, the information handling system 300 may further include one or more speakers and/or microphones 424 and a connection port 354 for connecting the information handling system 300 to another electronic device, dock, display, battery charger, and so on. In addition, information handling system 300 may include a headphone or speaker jack 428 and one or more cameras 336 on one or more sides of the housing 410. It should be noted that the information handling system 300 of FIG. 4 may include more or fewer elements than shown, in various arrangements, and the scope of the claimed subject matter is not limited in this respect.

As used herein, the terms "circuit" or "circuitry" may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group), and/or memory (shared, dedicated, or group) that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable hardware components that provide the described functionality. In some embodiments, the circuitry may be implemented in, or functions associated with the circuitry may be implemented by, one or more software or firmware modules. In some embodiments, circuitry may include logic, at least partially operable in hardware. Embodiments described herein may be implemented into a system using any suitably configured hardware and/or software.

Referring now to FIG. 5, example components of a wireless device such User Equipment (UE) device 500 in accordance with one or more embodiments will be discussed. User equipment (UE) 500 may correspond, for example, UE 114 or alternatively to eNB 110 and/or eNB 112, although the scope of the claimed subject matter is not limited in this respect. In some embodiments, UE device (or eNB device) 500 may include application circuitry 502, baseband circuitry 504, Radio Frequency (RF) circuitry 506, front-end module (FEM) circuitry 508 and one or more antennas 310, coupled together at least as shown and described herein. Application circuitry 502 may include one or more applications processors. For example, application circuitry 502 may include circuitry such as, but not limited to, one or more single- core or multi-core processors. The one or more processors may include any combination of general-purpose processors and dedicated processors, for example graphics processors, application processors, and so on. The processors may be coupled with and/or may include memory and/or storage and may be configured to execute instructions stored in the memory and/or storage to enable various applications and/or operating systems to run on the system.

Baseband circuitry 504 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. Baseband circuitry 504 may include one or more baseband processors and/or control logic to process baseband signals received from a receive signal path of RF circuitry 506 and to generate baseband signals for a transmit signal path of the RF circuitry 506. Baseband processing circuity 504 may interface with the application circuitry 502 for generation and processing of the baseband signals and for controlling operations of the RF circuitry 506. For example, in some embodiments, the baseband circuitry 504 may include a second generation (2G) baseband processor 504a, third generation (3G) baseband processor 504b, fourth generation (4G) baseband processor 504c, and/or one or more other baseband processors 504d for other existing generations, generations in development or to be developed in the future, for example fifth generation (5G), sixth generation (6G), and so on. Baseband circuitry 504, for example one or more of baseband processors 504a through 504d, may handle various radio control functions that enable communication with one or more radio networks via RF circuitry 506. The radio control functions may include, but are not limited to, signal modulation and/or demodulation, encoding and/or decoding, radio frequency shifting, and so on. In some embodiments, modulation and/or demodulation circuitry of baseband circuitry 504 may include Fast-Fourier Transform (FFT), precoding, and/or constellation mapping and/or demapping functionality. In some embodiments, encoding and/or decoding circuitry of baseband circuitry 504 may include convolution, tail-biting convolution, turbo, Viterbi, and/or Low Density Parity Check (LDPC) encoder and/or decoder functionality. Embodiments of modulation and/or demodulation and encoder and/or decoder functionality are not limited to these examples and may include other suitable functionality in other embodiments.

In some embodiments, baseband circuitry 504 may include elements of a protocol stack such as, for example, elements of an evolved universal terrestrial radio access network (EUTRAN) protocol including, for example, physical (PHY), media access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), and/or radio resource control (RRC) elements. Processor 504e of the baseband circuitry 504 may be configured to run elements of the protocol stack for signaling of the PHY, MAC, RLC, PDCP and/or RRC layers. In some embodiments, the baseband circuitry may include one or more audio digital signal processors (DSP) 504f. The one or more audio DSPs 504f may include elements for compression and/or decompression and/or echo cancellation and may include other suitable processing elements in other embodiments. Components of the baseband circuitry may be suitably combined in a single chip, a single chipset, or disposed on a same circuit board in some embodiments. In some embodiments, some or all of the constituent components of baseband circuitry 504 and application circuitry 502 may be implemented together such as, for example, on a system on a chip (SOC).

In some embodiments, baseband circuitry 504 may provide for communication compatible with one or more radio technologies. For example, in some embodiments, baseband circuitry 504 may support communication with an evolved universal terrestrial radio access network (EUTRAN) and/or other wireless metropolitan area networks (WMAN), a wireless local area network (WLAN), a wireless personal area network (WPAN). Embodiments in which baseband circuitry 504 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry.

RF circuitry 506 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, RF circuitry 506 may include switches, filters, amplifiers, and so on, to facilitate the communication with the wireless network. RF circuitry 506 may include a receive signal path which may include circuitry to down-convert RF signals received from FEM circuitry 508 and provide baseband signals to baseband circuitry 504. RF circuitry 506 may also include a transmit signal path which may include circuitry to up-convert baseband signals provided by the baseband circuitry 504 and provide RF output signals to FEM circuitry 508 for transmission.

In some embodiments, RF circuitry 506 may include a receive signal path and a transmit signal path. The receive signal path of RF circuitry 506 may include mixer circuitry 506a, amplifier circuitry 506b and filter circuitry 506c. The transmit signal path of RF circuitry 506 may include filter circuitry 506c and mixer circuitry 506a. RF circuitry 506 may also include synthesizer circuitry 506d for synthesizing a frequency for use by the mixer circuitry 506a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 506a of the receive signal path may be configured to down-convert RF signals received from FEM circuitry 508 based on the synthesized frequency provided by synthesizer circuitry 506d. Amplifier circuitry 506b may be configured to amplify the down-converted signals and the filter circuitry 506c may be a low-pass filter (LPF) or band-pass filter (BPF) configured to remove unwanted signals from the down-converted signals to generate output baseband signals. Output baseband signals may be provided to baseband circuitry 504 for further processing. In some embodiments, the output baseband signals may be zero-frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry 506a of the receive signal path may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

In some embodiments, mixer circuitry 506a of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized frequency provided by synthesizer circuitry 506d to generate RF output signals for FEM circuitry 508. The baseband signals may be provided by the baseband circuitry 504 and may be filtered by filter circuitry 506c. Filter circuitry 506c may include a low-pass filter (LPF), although the scope of the embodiments is not limited in this respect.

In some embodiments, mixer circuitry 506a of the receive signal path and the mixer circuitry 506a of the transmit signal path may include two or more mixers and may be arranged for quadrature down conversion and/or up conversion respectively. In some embodiments, mixer circuitry 506a of the receive signal path and the mixer circuitry 506a of the transmit signal path may include two or more mixers and may be arranged for image rejection, for example Hartley image rejection. In some embodiments, mixer circuitry 506a of the receive signal path and the mixer circuitry 506a may be arranged for direct down conversion and/or direct up conversion, respectively. In some embodiments, mixer circuitry 506a of the receive signal path and mixer circuitry 506a of the transmit signal path may be configured for super-heterodyne operation.

In some embodiments, the output baseband signals and the input baseband signals may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals and the input baseband signals may be digital baseband signals. In these alternate embodiments, RF circuitry 506 may include analog- to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry, and baseband circuitry 504 may include a digital baseband interface to communicate with RF circuitry 506. In some dual-mode embodiments, separate radio integrated circuit (IC) circuitry may be provided for processing signals for one or more spectra, although the scope of the embodiments is not limited in this respect.

In some embodiments, synthesizer circuitry 506d may be a fractional-N synthesizer or a fractional N/N+l synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry 506d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider. Synthesizer circuitry 506d may be configured to synthesize an output frequency for use by mixer circuitry 506a of RF circuitry 506 based on a frequency input and a divider control input. In some embodiments, synthesizer circuitry 506d may be a fractional N/N+l synthesizer.

In some embodiments, frequency input may be provided by a voltage controlled oscillator (VCO), although that is not a requirement. Divider control input may be provided by either baseband circuitry 504 or applications processor 502 depending on the desired output frequency. In some embodiments, a divider control input (e.g., N) may be determined from a look-up table based on a channel indicated by applications processor 502.

Synthesizer circuitry 506d of RF circuitry 506 may include a divider, a delay-locked loop (DLL), a multiplexer and a phase accumulator. In some embodiments, the divider may be a dual modulus divider (DMD) and the phase accumulator may be a digital phase accumulator (DP A). In some embodiments, the DMD may be configured to divide the input signal by either N or N+l , for example based on a carry out, to provide a fractional division ratio. In some example embodiments, the DLL may include a set of cascaded, tunable, delay elements, a phase detector, a charge pump and a D-type flip-flop. In these embodiments, the delay elements may be configured to break a VCO period up into Nd equal packets of phase, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

In some embodiments, synthesizer circuitry 506d may be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency may be a multiple of the carrier frequency, for example twice the carrier frequency, four times the carrier frequency, and so on, and used in conjunction with quadrature generator and divider circuitry to generate multiple signals at the carrier frequency with multiple different phases with respect to each other. In some embodiments, the output frequency may be a local oscillator (LO) frequency (fLO). In some embodiments, RF circuitry 1006 may include an in-phase and quadrature (IQ) and/or polar converter.

FEM circuitry 508 may include a receive signal path which may include circuitry configured to operate on RF signals received from one or more antennas 510, amplify the received signals and provide the amplified versions of the received signals to the RF circuitry 506 for further processing. FEM circuitry 508 may also include a transmit signal path which may include circuitry configured to amplify signals for transmission provided by RF circuitry 506 for transmission by one or more of the one or more antennas 510.

In some embodiments, FEM circuitry 508 may include a transmit/receive (TX/RX) switch to switch between transmit mode and receive mode operation. FEM circuitry 508 may include a receive signal path and a transmit signal path. The receive signal path of FEM circuitry 508 may include a low-noise amplifier (LNA) to amplify received RF signals and to provide the amplified received RF signals as an output, for example to RF circuitry 506. The transmit signal path of FEM circuitry 508 may include a power amplifier (PA) to amplify input RF signals, for example provided by RF circuitry 506, and one or more filters to generate RF signals for subsequent transmission, for example by one or more of antennas 510. In some embodiments, UE device 500 may include additional elements such as, for example, memory and/or storage, display, camera, sensor, and/or input/output (I/O) interface, although the scope of the claimed subject matter is not limited in this respect.

The following are example implementations of the subject matter described herein. It should be noted that any of the examples and the variations thereof described herein may be used in any permutation or combination of any other one or more examples or variations, although the scope of the claimed subject matter is not limited in these respects. Example one is directed to an apparatus of an evolved Node B (eNB) comprising one or more baseband processors to process a handover request received from a source eNB for a user equipment (UE) connected with the source eNB, and a memory to store handover request information, wherein the one or more baseband processors are to encode a mobility control information element MobilityControlInfo with an indication regarding a random-access channel (RACH) procedure for a handover of the UE from the source eNB. Example two may include the subject matter of example one or any of the examples described herein, wherein the indication regarding the RACH procedure indicates to the UE to skip the RACH procedure during the handover from the source eNB. Example three may include the subject matter of example one or any of the examples described herein, wherein the indication regarding the RACH procedure indicates to the UE that the eNB is a small cell. Example four may include the subject matter of example one or any of the examples described herein, further comprising a transceiver to transmit the mobility control information element to the UE via the source eNB using radio resource control (RRC) signaling. Example five may include the subject matter of example one or any of the examples described herein, further comprising a radio-frequency (RF) transceiver to receive a connection attempt from the UE to execute the handover according to the indication regarding the RACH procedure. Example six may include the subj ect matter of example one or any of the examples described herein, wherein the mobility control information element indicates to the UE to use pathloss as an estimation for initial access to the eNB for power ramping. Example seven may include the subject matter of example one or any of the examples described herein, wherein the mobility control information element configures a timing advance (TA) value of zero if the RACH procedure is to be skipped. Example eight is directed to an apparatus of a user equipment (UE) comprising one or more baseband processors to encode a measurement report of a target evolved Node B (eNB) to be sent to a source eNB, and a memory to store the measurement report, wherein the one or more baseband processors are to process mobility control information element Mobility Controllnfo received from the target eNB via the source eNB, the mobility control information element including an indication regarding a random-access channel (RACH) procedure for a handover to the target eNB if the target eNB is a small cell. Example nine may include the subject matter of example eight or any of the examples described herein, wherein the indication regarding the RACH procedure indicates to skip the RACH procedure during a handover rom the source eNB to the target eNB. Example ten may include the subject matter of example eight or any of the examples described herein, wherein the indication regarding the RACH procedure identifies the target eNB as a small cell. Example eleven may include the subject matter of example eight or any of the examples described herein, further comprising a radio-frequency (RF) transceiver to receive the mobility control information element from the target eNB via the source eNB using radio resource control (RRC) signaling. Example twelve may include the subject matter of example eight or any of the examples described herein, further comprising a radio-frequency (RF) transceiver to receive the mobility control information element from the source eNB in a handover command. Example thirteen may include the subject matter of example eight or any of the examples described herein, wherein the mobility control information element indicates to use pathloss as an estimation for initial access to the target eNB for power ramping. Example fourteen may include the subject matter of example eight or any of the examples described herein, wherein the mobility control information element configures a timing advance (TA) value of zero if the RACH procedure is to be skipped.

Example fifteen is directed to one or more computer readable media having instructions stored thereon that, if executed by an evolved Node B (eNB), result in processing a handover request received from a source eNB for a user equipment (UE) connected with the source eNB, and encoding a mobility control information element MobilityControlInfo with an indication regarding a random-access channel (RACH) procedure for a handover of the UE from the source eNB. Example sixteen may include the subject matter of example fifteen or any of the examples described herein, wherein the indication regarding the RACH procedure indicates to the UE to skip the RACH procedure during the handover from the source eNB. Example seventeen may include the subject matter of example fifteen or any of the examples described herein, wherein the indication regarding the RACH procedure indicates to the UE that the eNB is a small cell. Example eighteen may include the subject matter of example fifteen or any of the examples described herein, wherein the instructions, if executed, further result in causing a transceiver to transmit the mobility control information element to the UE via the source eNB using radio resource control (RRC) signaling. Example nineteen may include the subject matter of example fifteen or any of the examples described herein, wherein the instructions, if executed, further result in causing a radio-frequency (RF) transceiver to receive a connection attempt from the UE to execute the handover according to the indication regarding the RACH procedure. Example twenty may include the subject matter of example fifteen or any of the examples described herein, wherein the mobility control information element indicates to the UE to use pathloss as an estimation for initial access to the eNB for power ramping. Example twenty-one may include the subject matter of example fifteen or any of the examples described herein, wherein the mobility control information element configures a timing advance (TA) value of zero if the RACH procedure is to be skipped.

Example twenty-two is directed to one or more computer readable media having instructions stored thereon that, if executed by a user equipment (UE), result in encoding a measurement report of a target evolved Node B (eNB) to be sent to a source eNB, and processing a mobility control information element Mobility Controllnfo received from the target eNB via the source eNB, the mobility control information element including an indication regarding a random-access channel (RACH) procedure for a handover to the target eNB if the target eNB is a small cell. Example twenty -three may include the subject matter of example twenty -two or any of the examples described herein, wherein the indication regarding the RACH procedure indicates to skip the RACH procedure during a handover rom the source eNB to the target eNB. Example twenty-four may include the subject matter of example twenty -two or any of the examples described herein, wherein the indication regarding the RACH procedure identifies the target eNB as a small cell. Example twenty-five may include the subject matter of example twenty-two or any of the examples described herein, wherein the instructions, if executed, further result in causing a radio-frequency (RF) transceiver to receive the mobility control information element from the target eNB via the source eNB using radio resource control (RRC) signaling. Example twenty-six may include the subject matter of example twenty -two or any of the examples described herein, wherein the instructions, if executed, further result in causing a radio-frequency (RF) transceiver to receive the mobility control information element from the source eNB in a handover command. Example twenty-seven may include the subject matter of example twenty-two or any of the examples described herein, wherein the mobility control information element indicates to use pathloss as an estimation for initial access to the target eNB for power ramping. Example twenty-eight may include the subject matter of example twenty-two or any of the examples described herein, wherein the mobility control information element configures a timing advance (TA) value of zero if the RACH procedure is to be skipped. Example twenty-nine is directed to an apparatus of an evolved Node B (eNB) comprising means for processing a handover request received from a source eNB for a user equipment (UE) connected with the source eNB, and means for encoding a mobility control information element MobilityControlInfo with an indication regarding a random-access channel (RACH) procedure for a handover of the UE from the source eNB. Example thirty may include the subject matter of example twenty-nine or any of the examples described herein, wherein the indication regarding the RACH procedure indicates to the UE to skip the RACH procedure during the handover from the source eNB. Example thirty-one may include the subject matter of example twenty -nine or any of the examples described herein, wherein the indication regarding the RACH procedure indicates to the UE that the eNB is a small cell. Example thirty -two may include the subject matter of example twenty-nine or any of the examples described herein, further comprising means for causing a transceiver to transmit the mobility control information element to the UE via the source eNB using radio resource control (RRC) signaling. Example thirty-three may include the subject matter of example twenty -nine or any of the examples described herein, further comprising means for causing a radio-frequency (RF) transceiver to receive a connection attempt from the UE to execute the handover according to the indication regarding the RACH procedure. Example thirty-four may include the subject matter of example twenty -nine or any of the examples described herein, wherein the mobility control information element indicates to the UE to use pathloss as an estimation for initial access to the eNB for power ramping. Example thirty-five may include the subject matter of example twenty -nine or any of the examples described herein, wherein the mobility control information element configures a timing advance (TA) value of zero if the RACH procedure is to be skipped.

Example thirty-six is directed to an apparatus of a user equipment (UE) comprising means for encoding a measurement report of a target evolved Node B (eNB) to be sent to a source eNB, and means for processing a mobility control information element MobilityControlInfo received from the target eNB via the source eNB, the mobility control information element including an indication regarding a random-access channel (RACH) procedure for a handover to the target eNB if the target eNB is a small cell. Example thirty-seven may include the subject matter of example thirty-six or any of the examples described herein, wherein the indication regarding the RACH procedure indicates to skip the RACH procedure during a handover rom the source eNB to the target eNB. Example thirty-eight may include the subject matter of example thirty-six or any of the examples described herein, wherein the indication regarding the RACH procedure identifies the target eNB as a small cell. Example thirty -nine may include the subject matter of example thirty-six or any of the examples described herein, further comprising means for causing a radio-frequency (RF) transceiver to receive the mobility control information element from the target eNB via the source eNB using radio resource control (RRC) signaling. Example forty may include the subject matter of example thirty-six or any of the examples described herein, further comprising means for causing a radio-frequency (RF) transceiver to receive the mobility control information element from the source eNB in a handover command. Example forty-one may include the subject matter of example thirty-six or any of the examples described herein, wherein the mobility control information element indicates to use pathloss as an estimation for initial access to the target eNB for power ramping. Example forty-two may include the subject matter of example thirty-six or any of the examples described herein, wherein the mobility control information element configures a timing advance (TA) value of zero if the RACH procedure is to be skipped. Example forty-three is directed to machine-readable storage including machine-readable instructions, when executed, to realize an apparatus as claimed in any preceding claim.

Although the claimed subject matter has been described with a certain degree of particularity, it should be recognized that elements thereof may be altered by persons skilled in the art without departing from the spirit and/or scope of claimed subject matter. It is believed that the subject matter pertaining to RACH -less handover to a small cell and many of its attendant utilities will be understood by the forgoing description, and it will be apparent that various changes may be made in the form, construction and/or arrangement of the components thereof without departing from the scope and/or spirit of the claimed subject matter or without sacrificing all of its material advantages, the form herein before described being merely an explanatory embodiment thereof, and/or further without providing substantial change thereto. It is the intention of the claims to encompass and/or include such changes.

Claims

CLAIMS What is claimed is:

1. An apparatus of an evolved Node B (eNB), comprising:

one or more baseband processors to process a handover request received from a source eNB for a user equipment (UE) connected with the source eNB; and

a memory to store handover request information;

wherein the one or more baseband processors are to encode a mobility control information element Mobility Controllnfo with an indication regarding a random-access channel (RACH) procedure for a handover of the UE from the source eNB.

2. The apparatus of claim 1, wherein the indication regarding the RACH procedure indicates to the UE to skip the RACH procedure during the handover from the source eNB.

3. The apparatus of any of claims 1-2, wherein the indication regarding the RACH procedure indicates to the UE that the eNB is a small cell.

4. The apparatus of any of claims 1-3, further comprising a transceiver to transmit the mobility control information element to the UE via the source eNB using radio resource control (RRC) signaling.

5. The apparatus of any of claims 1-4, further comprising a radio-frequency (RF) transceiver to receive a connection attempt from the UE to execute the handover according to the indication regarding the RACH procedure.

6. The apparatus of any of claims 1-5, wherein the mobility control information element indicates to the UE to use pathloss as an estimation for initial access to the eNB for power ramping.

7. The apparatus of any of claims 1-6, wherein the mobility control information element configures a timing advance (TA) value of zero if the RACH procedure is to be skipped.

8. An apparatus of a user equipment (UE), comprising:

one or more baseband processors to encode a measurement report of a target evolved Node B (eNB) to be sent to a source eNB; and a memory to store the measurement report;

wherein the one or more baseband processors are to process mobility control information element MobilityControlInfo received from the target eNB via the source eNB, the mobility control information element including an indication regarding a random-access channel (RACH) procedure for a handover to the target eNB if the target eNB is a small cell.

9. The apparatus of claim 8, wherein the indication regarding the RACH procedure indicates to skip the RACH procedure during a handover rom the source eNB to the target eNB.

10. The apparatus of any of claims 8-9, wherein the indication regarding the RACH procedure identifies the target eNB as a small cell.

1 1. The apparatus of any of claims 8-10, further comprising a radio-frequency (RF) transceiver to receive the mobility control information element from the target eNB via the source eNB using radio resource control (RRC) signaling.

12. The apparatus of any of claims 8-1 1, further comprising a radio-frequency (RF) transceiver to receive the mobility control information element from the source eNB in a handover command.

13. The apparatus of any of claims 8-12, wherein the mobility control information element indicates to use pathloss as an estimation for initial access to the target eNB for power ramping.

14. The apparatus of any of claims 8-13, wherein the mobility control information element configures a timing advance (TA) value of zero if the RACH procedure is to be skipped.

15. One or more computer readable media having instructions stored thereon that, if executed by an evolved Node B (eNB), result in:

processing a handover request received from a source eNB for a user equipment (UE) connected with the source eNB; and

encoding a mobility control information element MobilityControlInfo with an indication regarding a random-access channel (RACH) procedure for a handover of the UE from the source eNB.

16. The one or more computer readable media of claim 15, wherein the indication regarding the RACH procedure indicates to the UE to skip the RACH procedure during the handover from the source eNB.

17. The one or more computer readable media of any of claims 15-16, wherein the indication regarding the RACH procedure indicates to the UE that the eNB is a small cell.

18. The one or more computer readable media of any of claims 15-17, wherein the instructions, if executed, further result in causing a transceiver to transmit the mobility control information element to the UE via the source eNB using radio resource control (RRC) signaling.

19. The one or more computer readable media of any of claims 15-18, wherein the instructions, if executed, further result in causing a radio-frequency (RF) transceiver to receive a connection attempt from the UE to execute the handover according to the indication regarding the RACH procedure.

20. The one or more computer readable media of any of claims 15-19, wherein the mobility control information element indicates to the UE to use pathloss as an estimation for initial access to the eNB for power ramping.

21. The one or more computer readable media of any of claims 15-20, wherein the mobility control information element configures a timing advance (TA) value of zero if the RACH procedure is to be skipped.

22. One or more computer readable media having instructions stored thereon that, if executed by a user equipment (UE), result in:

encoding a measurement report of a target evolved Node B (eNB) to be sent to a source eNB; and

processing a mobility control information element MobilityControlInfo received from the target eNB via the source eNB, the mobility control information element including an indication regarding a random-access channel (RACH) procedure for a handover to the target eNB if the target eNB is a small cell.

23. The one or more computer readable media of claim 22, wherein the indication regarding the RACH procedure indicates to skip the RACH procedure during a handover rom the source eNB to the target eNB.

24. The one or more computer readable media of any of claims 22-23, wherein the indication regarding the RACH procedure identifies the target eNB as a small cell.

25. The one or more computer readable media of any of claims 22-24, wherein the instructions, if executed, further result in causing a radio-frequency (RF) transceiver to receive the mobility control information element from the target eNB via the source eNB using radio resource control (RRC) signaling.

26. The one or more computer readable media of any of claims 22-25, wherein the instructions, if executed, further result in causing a radio-frequency (RF) transceiver to receive the mobility control information element from the source eNB in a handover command.

27. The one or more computer readable media of any of claims 22-26, wherein the mobility control information element indicates to use pathloss as an estimation for initial access to the target eNB for power ramping.

28. The one or more computer readable media of any of claims 22-27, wherein the mobility control information element configures a timing advance (TA) value of zero if the RACH procedure is to be skipped.