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73-626: An EV-DO channel has a bandwidth of 1.25 MHz, the same bandwidth size that IS-95A ( IS-95 ) and IS-2000 ( 1xRTT ) use, though the channel structure is very different. The back-end network is entirely packet-based , and is not constrained by restrictions typically present on a circuit switched network. The EV-DO feature of CDMA2000 networks provides access to mobile devices with forward link air interface speeds of up to 2.4 Mbit/s with Rel. 0 and up to 3.1 Mbit/s with Rev. A. The reverse link rate for Rel. 0 can operate up to 153 kbit/s, while Rev. A can operate at up to 1.8 Mbit/s. It

146-411: A 20 ms block interleaver, which is a 24 by 16 array. IS-95 and its use of CDMA techniques, like any other communications system, have their throughput limited according to Shannon's theorem . Accordingly, capacity improves with SNR and bandwidth. IS-95 has a fixed bandwidth, but fares well in the digital world because it takes active steps to improve SNR. With CDMA, signals that are not correlated with

219-518: A Qualcomm internal project, and the world of then-unproven competing digital cellular standards under which it was developed. The term IS-95 generically applies to the earlier set of protocol revisions, namely P_REV's one through five. P_REV=1 was developed under an ANSI standards process with documentation reference J-STD-008 . J-STD-008, published in 1995, was only defined for the then-new North American PCS band (Band Class 1, 1900 MHz). The term IS-95 properly refers to P_REV=1, developed under

292-463: A certain minimum level of service. The idea is to schedule mobiles reporting higher DRC indices more often, with the hope that those reporting worse conditions will improve in time. The system also incorporates Incremental Redundancy Hybrid ARQ . Each sub-packet of a multi-slot transmission is a turbo-coded replica of the original data bits. This allows mobiles to acknowledge a packet before all of its sub-sections have been transmitted. For example, if

365-399: A chip rate of 1,228,800 per second. Each signal is spread with a Walsh code of length 64 and a pseudo-random noise code ( PN code ) of length 2 , yielding a PN roll-over period of 80 3 {\displaystyle {\frac {80}{3}}} ms. For the reverse direction, radio signals are transmitted by the mobile. Reverse link transmissions are OQPSK in order to operate in

438-400: A data call would have unacceptable performance without RLP. Under IS-95B P_REV=5, it was possible for a user to use up to seven supplemental "code" (traffic) channels simultaneously to increase the throughput of a data call. Very few mobiles or networks ever provided this feature, which could in theory offer 115200 bit/s to a user. After convolution coding and repetition, symbols are sent to

511-485: A dialed telephone number) between mobile telephones and cell sites . CDMA transmits streams of bits ( PN codes ). CDMA permits several radios to share the same frequencies. Unlike time-division multiple access (TDMA), a competing system used in 2G GSM , all radios can be active all the time, because network capacity does not directly limit the number of active radios. Since larger numbers of phones can be served by smaller numbers of cell-sites, CDMA-based standards have

584-425: A direct evolution of the 1x (1xRTT) air interface standard, with its channels carrying only data traffic. The title of the 1xEV-DO standard document is "cdma2000 High Rate Packet Data Air Interface Specification", as cdma2000 (lowercase) is another name for the 1x standard, numerically designated as TIA-2000. Later, due to possible negative connotations of the word "only", the "DO"-part of the standard's name 1xEV-DO

657-431: A given mobile unit is determined by the mobile device itself; it listens to the traffic on the channel, and depending on the receive signal strength along with the perceived multi-path and fading conditions, makes a best guess as to what data-rate it can sustain while maintaining a reasonable frame error rate of 1-2%. It then communicates this information back to the serving sector in the form of an integer between 1 and 12 on

730-503: A handover may be necessary. The downlink (forward link) and/or uplink (reverse link) directions may be monitored. The handover may be requested by the phone or by the base station (BTS) of its source cell and, in some systems, by a BTS of a neighboring cell. The phone and the BTSes of the neighboring cells monitor each other's signals and the best target candidates are selected among the neighboring cells. In some systems, mainly based on CDMA,

803-482: A minimum. The receiver also uses the techniques of the rake receiver to improve SNR as well as perform soft handoff . Once a call is established, a mobile is restricted to using the traffic channel. A frame format is defined in the MAC for the traffic channel that allows the regular voice (vocoder) or data (RLP) bits to be multiplexed with signaling message fragments. The signaling message fragments are pieced together in

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876-409: A mobile transmits a DRC index of 3 and is scheduled to receive data, it will expect to get data during four time slots. If after decoding the first slot the mobile is able to determine the entire data packet, it can send an early acknowledgement back at that time; the remaining three sub-packets will be cancelled. If however the packet is not acknowledged, the network will proceed with the transmission of

949-444: A new clearer or less fading channel. In addition to the above classification of inter-cell and intra-cell classification of handovers, they also can be divided into hard and soft handovers: Handover can also be classified on the basis of handover techniques used. Broadly they can be classified into three types: An advantage of the hard handover is that at any moment in time one call uses only one channel. The hard handover event

1022-473: A significant economic advantage over TDMA-based standards, or the oldest cellular standards that used frequency-division multiplexing . In North America, the technology competed with Digital AMPS (IS-136), a TDMA-based standard, as well as with the TDMA-based GSM. It was supplanted by IS-2000 (CDMA2000), a later CDMA-based standard. cdmaOne's technical history is reflective of both its birth as

1095-462: A soft handover, is referred to as the active set . If the search finger finds a sufficiently-strong signal (in terms of high Ec/Io or RSCP) from a new cell this cell is added to the active set. The cells in the neighbour list (called in CDMA neighbouring set ) are checked more frequently than the rest and thus a handover with a neighbouring cell is more likely, however a handover with others cells outside

1168-475: A target candidate may be selected among the cells which are not in the neighbor list. This is done in an effort to reduce the probability of interference due to the aforementioned near–far effect. In analog systems the parameters used as criteria for requesting a hard handover are usually the received signal power and the received signal-to-noise ratio (the latter may be estimated in an analog system by inserting additional tones, with frequencies just outside

1241-430: A temporary interruption to the call. One advantage of the soft handovers is that the connection to the source cell is broken only when a reliable connection to the target cell has been established and therefore the chances that the call will be terminated abnormally due to failed handovers are lower. However, by far a bigger advantage comes from the mere fact that simultaneously channels in multiple cells are maintained and

1314-696: A user moves into a cell when all available channels are in use, the user's call must be terminated. Also, there is the problem of signal interference where adjacent cells overpower each other resulting in receiver desensitization. There are also inter-technology handovers where a call's connection is transferred from one access technology to another, e.g. a call being transferred from GSM to UMTS or from CDMA IS-95 to CDMA2000 . The 3GPP UMA/GAN standard enables GSM/UMTS handoff to Wi-Fi and vice versa. Different systems have different methods for handling and managing handoff request. Some systems handle handoff in same way as they handle new originating call. In such system

1387-529: Is a multi-carrier evolution of the Rev. A specification. It maintains the capabilities of EV-DO Rev. A, and provides the following enhancements: Qualcomm early on realized that EV-DO was a stop-gap solution, and foresaw an upcoming format war between LTE and determined that a new standard would be needed. Qualcomm originally called this technology EV-DV (Evolution Data and Voice). As EV-DO became more pervasive, EV-DV evolved into EV-DO Rev C. The EV-DO Rev. C standard

1460-465: Is adjusted up or down 800 times a second, as indicated by the serving sector (similar to 1x ). All of the reverse link channels are combined using code division and transmitted back to the base station using BPSK where they are decoded. The maximum speed available for user data is 153.2 kbit/s, but in real-life conditions this is rarely achieved. Typical speeds achieved are between 20-50 kbit/s. Revision A of EV-DO makes several additions to

1533-623: Is decoded at each possible rate, and using the quality metrics of the Viterbi decoder , the correct result is chosen. Traffic channels may also carry circuit-switch data calls in IS-95. The variable-rate traffic frames are generated using the IS-95 Radio Link Protocol (RLP) . RLP provides a mechanism to improve the performance of the wireless link for data. Where voice calls might tolerate the dropping of occasional 20 ms frames,

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1606-529: Is divided into slots, each being 1.667 ms long. In addition to user traffic, overhead channels are interlaced into the stream, which include the 'pilot', which helps the mobile find and identify the channel, the Media Access Channel (MAC) which tells the mobile devices when their data is scheduled, and the 'control channel', which contains other information the network needs the mobile devices to know. The modulation to be used to communicate with

1679-404: Is indeed very short and usually is not perceptible by the user. In the old analog systems it could be heard as a click or a very short beep; in digital systems it is unnoticeable. Another advantage of the hard handover is that the phone's hardware does not need to be capable of receiving two or more channels in parallel, which makes it cheaper and simpler. A disadvantage is that if a handover fails

1752-402: Is interfered or fading, soft handovers bring a significant improvement to the reliability of the calls in these places by making the interference or the fading in a single channel not critical. This advantage comes at the cost of more complex hardware in the phone, which must be capable of processing several channels in parallel. Another price to pay for soft handovers is use of several channels in

1825-473: Is more common in academic research publications and literature, while handoff is slightly more common within the IEEE and ANSI organisations. In telecommunications there may be different reasons why a handover might be conducted: The most basic form of handover is when a phone call in progress is redirected from its current cell (called source ) to a new cell (called target ). In terrestrial networks

1898-451: Is roaming, and that it is "in service". BTSs transmit at least one, and as many as seven, paging channel s starting with Walsh code 1. The paging channel frame time is 20 ms, and is time aligned to the IS-95 system (i.e. GPS) 2-second roll-over. There are two possible rates used on the paging channel: 4800 bit/s or 9600 bit/s. Both rates are encoded to 19200 symbols per second. The paging channel contains signaling messages transmitted from

1971-533: Is termed Interim Standard 95B (IS-95B) Phase II . The IS-95B standards track provided for a merging of the TIA and ANSI standards tracks under the TIA, and was the first document that provided for interoperation of IS-95 mobile handsets in both band classes (dual-band operation). P_REV=4 was by far the most popular variant of IS-95, with P_REV=5 only seeing minimal uptake in South Korea. P_REV=6 and beyond fall under

2044-517: Is transmitted 32 bits per frame, encoded to 128 symbols, yielding a rate of 1200 bit/s. The Sync Channel Message contains information about the network, including the PN offset used by the BTS sector. Once a mobile has found a strong pilot channel, it listens to the sync channel and decodes a Sync Channel Message to develop a highly accurate synchronization to system time. At this point the mobile knows whether it

2117-480: The 2G (second-generation) technologies have this feature (e.g. GSM, D-AMPS / IS-136 , etc.). On the other hand, all CDMA based technologies, 2G and 3G (third-generation), have soft handovers. On one hand, this is facilitated by the possibility to design not so expensive phone hardware supporting soft handovers for CDMA and on the other hand, this is necessitated by the fact that without soft handovers CDMA networks may suffer from substantial interference arising due to

2190-522: The CDMA2000 umbrella. Besides technical improvements, the IS-2000 documents are much more mature in terms of layout and content. They also provide backwards-compatibility to IS-95. The IS-95 standards describe an air interface , a set of protocols used between mobile units and the network. IS-95 is widely described as a three-layer stack, where L1 corresponds to the physical ( PHY ) layer, L2 refers to

2263-544: The Media Access Control (MAC) and Link-Access Control (LAC) sublayers, and L3 to the call-processing state machine. IS-95 defines the transmission of signals in both the forward (network-to-mobile) and reverse (mobile-to-network) directions. In the forward direction, radio signals are transmitted by base stations (BTS's). Every BTS is synchronized with a GPS receiver so transmissions are tightly controlled in time. All forward transmissions are QPSK with

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2336-572: The Telecommunications Industry Association (TIA) standards process, for the North American cellular band (Band Class 0, 800 MHz) under roughly the same time frame. IS-95 offered interoperation (including handoff) with the analog cellular network. For digital operation, IS-95 and J-STD-008 have most technical details in common. The immature style and structure of both documents are highly reflective of

2409-541: The "Digital Rate Control" (DRC) channel. Alternatively, the mobile can select a "null" rate (DRC 0), indicating that the mobile either cannot decode data at any rate, or that it is attempting to hand off to another serving sector. The DRC values are as follows: Another important aspect of the EV-DO forward link channel is the scheduler. The scheduler most commonly used is called " proportional fair ". It's designed to maximize sector throughput while also guaranteeing each user

2482-441: The "standardizing" of Qualcomm's internal project. P_REV=2 is termed Interim Standard 95A (IS-95A) . IS-95A was developed for Band Class 0 only, as in incremental improvement over IS-95 in the TIA standards process. P_REV=3 is termed Technical Services Bulletin 74 (TSB-74) . TSB-74 was the next incremental improvement over IS-95A in the TIA standards process. P_REV=4 is termed Interim Standard 95B (IS-95B) Phase I , and P_REV=5

2555-449: The ACK channel (used for HARQ ). Only the reverse link has any sort of power control , because the forward link is always transmitted at full power for use by all the mobiles. The reverse link has both open loop and closed loop power control. In the open loop, the reverse link transmission power is set based upon the received power on the forward link. In the closed loop, the reverse link power

2628-429: The IS-95 network to squeeze more users into the same radio spectrum. Active (slow) power control is also used on the forward traffic channels, where during a call, the mobile sends signaling messages to the network indicating the quality of the signal. The network will control the transmitted power of the traffic channel to keep the signal quality just good enough, thereby keeping the noise level seen by all other users to

2701-581: The LAC, where complete signaling messages are passed on to Layer 3. cdmaOne was used in the following areas: Handoff In cellular telecommunications , handover , or handoff , is the process of transferring an ongoing call or data session from one channel connected to the core network to another channel. In satellite communications it is the process of transferring satellite control responsibility from one earth station to another without loss or interruption of service. American English uses

2774-577: The UMB system was to be based upon Internet networking technologies running over a next generation radio system, with peak rates of up to 280 Mbit/s. Its designers intended for the system to be more efficient and capable of providing more services than the technologies it was intended to replace. To provide compatibility with the systems it was intended to replace, UMB was to support handoffs with other technologies including existing CDMA2000 1X and 1xEV-DO systems. UMB's use of OFDMA would have eliminated many of

2847-587: The Walsh and PN sequences and transmitted. BTSs transmit a sync channel spread with Walsh code 32. The sync channel frame is 80 3 {\displaystyle {\frac {80}{3}}} ms long, and its frame boundary is aligned to the pilot. The sync channel continually transmits a single message, the Sync Channel Message , which has a length and content dependent on the P_REV. The message

2920-454: The call as the subscriber is moving out of the area covered by the source cell and entering the area of the target cell. A special case is possible, in which the source and the target are one and the same cell and only the used channel is changed during the handover. Such a handover, in which the cell is not changed, is called intra-cell handover. The purpose of intra-cell handover is to change one channel, which may be interfered or fading with

2993-498: The call could only fail if all of the channels are interfered or fade at the same time. Fading and interference in different channels are unrelated and therefore the probability of them taking place at the same moment in all channels is very low. Thus the reliability of the connection becomes higher when the call is in a soft handover. Because in a cellular network the majority of the handovers occur in places of poor coverage, where calls would frequently become unreliable when their channel

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3066-399: The call may be temporarily disrupted or even terminated abnormally. Technologies which use hard handovers, usually have procedures which can re-establish the connection to the source cell if the connection to the target cell cannot be made. However re-establishing this connection may not always be possible (in which case the call will be terminated) and even when possible the procedure may cause

3139-469: The captured voice-frequency band at the transmitter and assessing the form of these tones at the receiver). In non-CDMA 2G digital systems the criteria for requesting hard handover may be based on estimates of the received signal power, bit error rate (BER) and block error/erasure rate (BLER), received quality of speech ( RxQual ), distance between the phone and the BTS (estimated from the radio signal propagation delay) and others. In CDMA systems, 2G and 3G,

3212-500: The channel of interest (such as other PN offsets from adjacent cellular base stations) appear as noise, and signals carried on other Walsh codes (that are properly time aligned) are essentially removed in the de-spreading process. The variable-rate nature of traffic channels provide lower-rate frames to be transmitted at lower power causing less noise for other signals still to be correctly received. These factors provide an inherently lower noise level than other cellular technologies allowing

3285-506: The cost of implementing them for analog technologies is prohibitively high and none of the technologies that were commercially successful in the past (e.g. AMPS , TACS , NMT , etc.) had this feature. Of the digital technologies, those based on FDMA also face a higher cost for the phones (due to the need to have multiple parallel radio-frequency modules) and those based on TDMA or a combination of TDMA/FDMA, in principle, allow not so expensive implementation of soft handovers. However, none of

3358-741: The disadvantages of the CDMA technology used by its predecessor, including the "breathing" phenomenon, the difficulty of adding capacity via microcells, the fixed bandwidth sizes that limit the total bandwidth available to handsets, and the near complete control by one company of the required intellectual property. While capacity of existing Rel. B networks can be increased 1.5-fold by using EVRC-B voice codec and QLIC handset interference cancellation, 1x Advanced and EV-DO Advanced offers up to 4x network capacity increase using BTS interference cancellation (reverse link interference cancellation), multi-carrier links, and smart network management technologies. In November 2008, Qualcomm , UMB's lead sponsor, announced it

3431-399: The earlier of which were limited to rate set 1, and were responsible for some user complaints of poor voice quality. More sophisticated vocoders, taking advantage of modern DSPs and rate set 2, remedied the voice quality situation and are still in wide use in 2005. The mobile receiving a variable-rate traffic frame does not know the rate at which the frame was transmitted. Typically, the frame

3504-501: The forward link (from the tower to the mobile). This means that a single mobile has full use of the forward traffic channel within a particular geographic area (a sector) during a given slot of time. Using this technique, EV-DO is able to modulate each user’s time slot independently. This allows the service of users in favorable RF conditions with very complex modulation techniques while also serving users in poor RF conditions with simpler (and more redundant) signals. The forward channel

3577-439: The list is called neighbor list . Creating such a list for a given cell is not trivial and specialized computer tools are used. They implement different algorithms and may use for input data from field measurements or computer predictions of radio wave propagation in the areas covered by the cells. During a call one or more parameters of the signal in the channel in the source cell are monitored and assessed in order to decide when

3650-638: The most common criterion for requesting a handover is Ec/Io ratio measured in the pilot channel ( CPICH ) and/or RSCP . In CDMA systems, when the phone in soft or softer handover is connected to several cells simultaneously, it processes the received in parallel signals using a rake receiver . Each signal is processed by a module called rake finger . A usual design of a rake receiver in mobile phones includes three or more rake fingers used in soft handover state for processing signals from as many cells and one additional finger used to search for signals from other cells. The set of cells, whose signals are used during

3723-450: The neighbor list is also allowed (unlike in GSM, IS-136/DAMPS, AMPS, NMT, etc.). There are occurrences where a handoff is unsuccessful. Much research has been dedicated to this problem. The source of the problem was discovered in the late 1980s. Because frequencies cannot be reused in adjacent cells, when a user moves from one cell to another, a new frequency must be allocated for the call. If

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3796-491: The network is assigned a PN offset in steps of 64 chips. There is no data carried on the forward pilot. With its strong autocorrelation function, the forward pilot allows mobiles to determine system timing and distinguish different BTSs for handoff . When a mobile is "searching", it is attempting to find pilot signals on the network by tuning to particular radio frequencies and performing a cross-correlation across all possible PN phases. A strong correlation peak result indicates

3869-431: The network to all idle mobiles. A set of messages communicate detailed network overhead to the mobiles, circulating this information while the paging channel is free. The paging channel also carries higher-priority messages dedicated to setting up calls to and from the mobiles. When a mobile is idle, it is mostly listening to a paging channel. Once a mobile has parsed all the network overhead information, it registers with

3942-438: The network to support just a single call. This reduces the number of remaining free channels and thus reduces the capacity of the network. By adjusting the duration of soft handovers and the size of the areas in which they occur, the network engineers can balance the benefit of extra call reliability against the price of reduced capacity. While theoretically speaking soft handovers are possible in any technology, analog or digital,

4015-412: The network, then optionally enters slotted-mode . Both of these processes are described in more detail below. The Walsh space not dedicated to broadcast channels on the BTS sector is available for traffic channel s. These channels carry the individual voice and data calls supported by IS-95. Like the paging channel, traffic channels have a frame time of 20ms. Since voice and user data are intermittent,

4088-406: The optimal range of the mobile's power amplifier. Like the forward link, the chip rate is 1,228,800 per second and signals are spread with Walsh codes and the pseudo-random noise code, which is also known as a Short Code. Every BTS dedicates a significant amount of output power to a pilot channel , which is an unmodulated PN sequence (in other words, spread with Walsh code 0). Each BTS sector in

4161-400: The protocol while keeping it completely backwards compatible with Release 0. These changes included the introduction of several new forward link data rates that increase the maximum burst rate from 2.45 Mbit/s to 3.1 Mbit/s. Also included were protocols that would decrease connection establishment time (called enhanced access channel MAC), the ability for more than one mobile to share

4234-411: The proximity of a BTS. Other forward channels, selected by their Walsh code, carry data from the network to the mobiles. Data consists of network signaling and user traffic. Generally, data to be transmitted is divided into frames of bits. A frame of bits is passed through a convolutional encoder, adding forward error correction redundancy, generating a frame of symbols. These symbols are then spread with

4307-555: The remaining parts until all have been transmitted or the packet is acknowledged. The reverse link (from the mobile back to the Base Transceiver Station ) on EV-DO Rel. 0 operates very similar to that of CDMA2000 1xRTT . The channel includes a reverse link pilot (helps with decoding the signal) along with the user data channels. Some additional channels that do not exist in 1x include the DRC channel (described above) and

4380-409: The same timeslot (multi-user packets) and the introduction of QoS flags. All of these were put in place to allow for low latency, low bit rate communications such as VoIP . The additional forward rates for EV-DO Rev. An are: In addition to the changes on the forward link, the reverse link was enhanced to support higher complexity modulation (and thus higher bit rates). An optional secondary pilot

4453-527: The so-called near–far effect. In all current commercial technologies based on FDMA or on a combination of TDMA/FDMA (e.g. GSM, AMPS, IS-136/DAMPS, etc.) changing the channel during a hard handover is realised by changing the pair of used transmit/receive frequencies . For the practical realisation of handovers in a cellular network each cell is assigned a list of potential target cells, which can be used for handing over calls from this source cell to them. These potential target cells are called neighbors and

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4526-401: The source and the target cells may be served from two different cell sites or from one and the same cell site (in the latter case the two cells are usually referred to as two sectors on that cell site). Such a handover, in which the source and the target are different cells (even if they are on the same cell site) is called inter-cell handover. The purpose of inter-cell handover is to maintain

4599-532: The term handoff , and this is most commonly used within some American organizations such as 3GPP2 and in American originated technologies such as CDMA2000 . In British English the term handover is more common, and is used within international and European organisations such as ITU-T , IETF , ETSI and 3GPP , and standardised within European originated standards such as GSM and UMTS . The term handover

4672-489: The traffic channels support variable-rate operation. Every 20 ms frame may be transmitted at a different rate, as determined by the service in use (voice or data). P_REV=1 and P_REV=2 supported rate set 1 , providing a rate of 1200, 2400, 4800, or 9600 bit/s. P_REV=3 and beyond also provided rate set 2 , yielding rates of 1800, 3600, 7200, or 14400 bit/s. For voice calls, the traffic channel carries frames of vocoder data. A number of different vocoders are defined under IS-95,

4745-501: Was added, which is activated by the mobile when it tries to achieve enhanced data rates. To combat reverse link congestion and noise rise, the protocol calls for each mobile to be given an interference allowance which is replenished by the network when the reverse link conditions allow it. The reverse link has a maximum rate of 1.8 Mbit/s, but under normal conditions users experience a rate of approximately 500-1000 Kbit/s but with more latency than DOCSIS and DSL . EV-DO Rev. B

4818-411: Was changed to stand for "Data Optimized", the full name - EV-DO now stands for "Evolution-Data Optimized." The 1x prefix has been dropped by many of the major carriers, and is marketed simply as EV-DO. This provides a more market-friendly emphasis of the technology being data-optimized. The primary characteristic that differentiates an EV-DO channel from a 1xRTT channel is that it is time multiplexed on

4891-436: Was designed to be operated end-to-end as an IP-based network , and can support any application which can operate on such a network and bit rate constraints. There have been several revisions of the standard, starting with Release 0 (Rel. 0). This was later expanded upon with Revision A (Rev. A) to support quality of service (to improve latency) and higher rates on the forward and reverse link. In late 2006, Revision B (Rev. B)

4964-580: Was developed by Qualcomm in 1999 to meet IMT-2000 requirements for a greater-than-2 Mbit/s down link for stationary communications, as opposed to mobile communication (i.e., moving cellular phone service). Initially, the standard was called High Data Rate (HDR), but was renamed to 1xEV-DO after it was ratified by the International Telecommunication Union (ITU) under the designation TIA-856 . Originally, 1xEV-DO stood for "1x Evolution-Data Only", referring to its being

5037-476: Was ending development of the technology, favoring LTE instead. This followed the announcement that most CDMA carriers chose to adopt either WiMAX or LTE standard as their 4G technology. In fact no carrier had announced plans to adopt UMB. However, during the ongoing development process of the 4G technology, 3GPP added some functionalities to LTE, allowing it to become a sole upgrade path for all wireless networks. IS-95 Interim Standard 95 ( IS-95 )

5110-484: Was intended to be a fourth-generation technology, which would make it compete with LTE and WiMAX . These technologies use a high bandwidth, low latency, underlying TCP/IP network with high level services such as voice built on top. Widespread deployment of 4G networks promises to make applications that were previously not feasible not only possible but ubiquitous. Examples of such applications include mobile high definition video streaming and mobile gaming. Like LTE,

5183-490: Was published, whose features include the ability to bundle multiple carriers to achieve even higher rates and lower latencies (see TIA-856 Rev. B below). The upgrade from EV-DO Rev. A to Rev. B involves a software update of the cell site modem, and additional equipment for new EV-DO carriers. Existing cdma2000 operators may have to retune some of their existing 1xRTT channels to other frequencies, as Rev. B requires all DO carriers be within 5 MHz. The initial design of EV-DO

5256-414: Was specified by 3GPP2 to improve the CDMA2000 mobile phone standard for next generation applications and requirements. It was proposed by Qualcomm as the natural evolution path for CDMA2000 and the specifications were published by 3GPP2 (C.S0084-*) and TIA (TIA-1121) in 2007 and 2008 respectively. The brand name UMB (Ultra Mobile Broadband) was introduced in 2006 as a synonym for this standard. UMB

5329-517: Was the first digital cellular technology that used code-division multiple access (CDMA). It was developed by Qualcomm and later adopted as a standard by the Telecommunications Industry Association in TIA/EIA/IS-95 release published in 1995. The proprietary name for IS-95 is cdmaOne . It is a 2G mobile telecommunications standard that uses CDMA, a multiple access scheme for digital radio , to send voice, data and signaling data (such as

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