OWA320010 HSPA & HSPA+ Introduction ISSUE 1.00_staffsHSPA & HSPA+ Introduction ISSUE

HSPA & HSPA+ Introduction P-0

Confidential Information of Huawei. No Spreading Without Permission


� Mobile network data rate evolution

� WCDMA data transmission evolved from GSM/GPRS, inheriting much of the upper

layer functionality directly from those systems. The first commercial deployments of

WCDMA are based on a version of the standards called Release 99, with HSDPA

introduced in Release 5 to offer higher speed Downlink data services.

� Enhanced Data rates for GSM Evolution (EDGE) is another system in the GSM/GPRS

family that some operators have deployed as an intermediate step before

deploying WCDMA.

� Release 6 introduces the High Speed Uplink Packet Access (HSUPA) to provide � Release 6 introduces the High Speed Uplink Packet Access (HSUPA) to provide

faster data services for the Uplink.

� For HSUPA (Uplink) the theoretical maximum achievable peak data rate is 5.76

Mbps, while for HSDPA (Downlink) it is 14.4 Mbps.

� Release 7 introduces HSPA+ to increase data rate and system capacity. Some new

features are used such as MIMO, DL 64QAM, CELL_FACH operation and etc.

� Release 8 introduces more new features to HSPA+ such as DL MIMO+64QAM, DC-

HSDPA (Dual Carrier-HSDPA), UL 16QAM and etc. The DL/UL peak data rate can

reach 42Mbps/11.5Mbps.



� Data Services and High Speed Downlink Packet Access (HSDPA)

� Data Services are expected to grow significantly within the next few years. Current

2.5G and 3G operators are already reporting that a significant proportion of usage

is now due to data, implying an increasing demand for high-data-rate, content-rich

multimedia services. Although current Release 99 WCDMA systems offer a

maximum practical data rate of 384 kbps, the 3rd Generation Partnership Project

(3GPP) have included in Release 5 of the specifications a new high-speed, low-

delay feature referred to as High Speed Downlink Packet Access (HSDPA).

� HSDPA provides significant enhancements to the Downlink compared to WCDMA � HSDPA provides significant enhancements to the Downlink compared to WCDMA

Release 99 in terms of peak data rate, cell throughput, and round trip delay. This is

achieved through the implementation of a fast channel control and allocation

mechanism that employs such features as Adaptive Modulation and Coding and

fast Hybrid Automatic Repeat Request (HARQ). Shorter Physical Layer frames are

also employed.



� Data Services are expected to grow significantly within the next few years. Current 2.5G

and 3G operators are already reporting that a significant proportion of usage is now

devoted to data, implying an increasing demand for high-data-rate, content-rich

multimedia services. Although current Release 99 WCDMA systems offer a maximum

practical data rate in Uplink of 384 kbps, the 3rd Generation Partnership Project (3GPP)

has included in Release 6 of the specifications a new high-speed, low-delay feature called

High Speed Uplink Packet Access (HSUPA).

� HSUPA provides significant enhancements to the Uplink compared to WCDMA Release 99

in terms of peak data rate, cell throughput, and latency. This is achieved through the

implementation of a fast resource control and allocation mechanism that employs such

features as Adaptive Coding, fast Hybrid Automatic Repeat Request (HARQ) and Shorter

Physical Layer frames. With the addition of HSUPA, a better balance between Downlink

HSDPA and Uplink traffic performance is also achieved.

� The High Speed Uplink Packet Access (HSUPA) is a 3GPP Release 6 feature, also called

Enhanced Uplink (EUL) or Enhanced DCH (E-DCH).



� The CQI table consists of 30 entries, where each entry indicates a different TFRC. Transport

Format Resource Combination (TFRC) points to the combination of number of HS-PDSCH

channelization codes, modulation scheme, and the HS-DSCH transport block size. The 5-bit

CQI reported by a UE is an index into this table containing all possible TFRC combinations

for that UE category. The TFRC combinations are different for UEs with different HS-DSCH

UE categories because of the differences in the UE capabilities. Along with TFRC, CQI may

also indicate a power offset relative to the current HS-PDSCH power. The CQI table shown

in the slide is for UE categories supporting up to 15 HS-PDSCH codes (HSDPA terminal

category 10).



� Example of Code Allocation for a HSDPA cell:



� Shared channel transmission implies that a certain amount of radio resource of a cell

(code and power) is seem as a common resource that is dynamically shared between

users.

� The NodeB transmit power allocation algorithm is not specified by the standard.



� There can be multiple (up to 15) HS-PDSCHs in a serving cell, which enables use of both

time division and code division multiple access methods.


WCDMA HSDPA Principles

� WCDMA R99 uses QPSK data modulation for downlink transmission. To support higher

data rate, higher order data modulation, such as 16QAM can be used.

� Compared to QPSK modulation, higher order modulation is more bandwidth efficient i.e.

can carry more bits per Hertz.



� The basic idea of fast scheduling is to transmit at the fading peaks of the channel in order

to increase the throughput and to use resource more efficiently. But this might lead to

large variations in data rate of the users. The trade-off is between the cell throughput and

fairness against users.

� There are a number of scheduling algorithms that take into consideration the trade-off

between throughput and fairness:

� Round Robin (RR): radio resource are allocated to communication links on a

sequential basis, not taking into account the instantaneous radio channel

conditions experienced by each link.conditions experienced by each link.

� Max C/I: for maximum cell throughput ,the radio resource should be as much as

possible be allocated to communication links with the best instantaneous channel

condition.

� Proportional Fair (PF): allocates the channel to the user with relatively best channel

quality.

� Enhanced Proportional Fair (EPF): allocates the channel to the user according to

relatively best channel quality, fairness, guarantee bit rate requirement.


WCDMA HSDPA Principles

� In a Release 99 PS network, the NAS layer protocols are terminated at the SGSN. RRC,

RLC,and MAC protocols are terminated at the RNC. The Physical Layer protocol is

terminated at the NodeB.

� The Release 5 specifications define a new sublayer of MAC called MAC-hs, which

implements the MAC protocols and procedures for HSDPA. This sublayer operates at the

NodeBand the UE.

� UTRAN MAC-hs is responsible for fast scheduling of the HS-PDSCHs. The scheduler

determines:

� To which UEs the channels are assigned.


� To which UEs the channels are assigned.

� How much data to send.

� Which modulation scheme to use.

� Whether to send new data or retransmitted data.

� Which redundancy version to send.

� UE MAC-hs is responsible for:

� Sending ACK or NACK after decoding a block.

� Re-ordering data blocks before submitting to upper layers, if retransmissions

caused data to be received out of order.


� Compared to R99 UL DCH, the enhance DCH specified for HSUPA in Release 6 offers the

following features:

� Shorter TTI of 2ms: which can reduce the latency and can be scheduled faster

� Lower SF: which can increase physical channel symbol rate , higher peak data rate

is available

� Uplink L1 HARQ throughput: improve physical layer performance with fast

retransmissions

� New transport and physical channels

Fast resource control: with new MAC entities in NodeB, radio resource can be � Fast resource control: with new MAC entities in NodeB, radio resource can be

scheduled faster to optimize the total throughput



� Similar to HSDPA, HSUPA implements fast resource allocation and control with a scheduler

in the NodeB. While the HSDPA scheduler accommodates a common resource to several

users, the HSUPA scheduler has a different task: it coordinates the reception of data

transmitted from several UEs to a single NodeB. This can be regarded as a very fast

resource allocation of a dedicated channel (E-DCH), rather than a sharing of a common

channel (HS-DSCH).

� On one side, each UE will tend to transmit as much as possible based on channel

conditions, the amount of data in the buffer, and the power available. On the other side,

the scheduler will try to satisfy each connected UE while preventing overloading and

maximizing resource utilization and cell throughput.



� This slide illustrates HSUPA operation :

� 1. The UE asks the NodeB for a grant to transmit data on uplink.

� 2. If the Node B allows the UE to send data, it indicates the grant in terms of

Traffic-to-Pilot (T/P) ratio. The grant is valid until a new grant is provided.

� 3. After receiving the grant, the UE can transmit data starting at any TTI and may

include further requests. Data are transmitted according to the selected transport

format, which is also signaled to the NodeB.

� 4. After the Node B decodes the data, it sends an ACK or NAK back to the UE. If

the NodeB sends a NAK, the UE may send the data again with a retransmission.the NodeB sends a NAK, the UE may send the data again with a retransmission.



� This slide illustrates a data transmission request from the UE through scheduling

information (SI), by which the UE asks the Node B for a grant to transmit data on Uplink E-

DCH.

� UE power availability and UE buffer status are combined to determine the scheduling

information.



� This slide illustrates an HSUPA absolute grant assignment upon request from the UE. The

grant is determined based on uplink interference situation (Rise-over-Thermal noise) at the

NodeB receiver and on the UE transmission requests and level of satisfaction.

� The Node B indicates the Traffic-to-Pilot (T/P) grant by downlink grant channel. The grant

is valid until a new grant is given or modified.

� SI is scheduling information. It includes the UL power usage and the buffer status of UE.

UE uses SI to request resource from NodeB.



� This slide illustrates an HSUPA Data Transmission for scheduled grants.

� After receiving the grant, the UE can transmit data starting at any TTI and may include

additional scheduling information. The transport format is first selected based on the

received grant, on the available power and on the data in the buffer.

� Data are transmitted on a set of E-DPDCH channels, and transport format Information is

signaled to the Node B on the corresponding E-DPCCH. The Happy Bit (Happy Bit indicates

the UE’s level of satisfaction. ) is also included.



� This slide illustrates the acknowledgment of data at the NodeB and HARQ retransmission.

� After the NodeB attempts to decode the data, it sends an ACK or NACK to the UE. If the

NodeB sends a NACK, the UE may send the data again with a fast retransmission.



� The following assumptions are needed to achieve the theoretical maximum data rate of

5.76 Mbps:

� Lower channel coding gain – Using an effective code rate of 1 increases the data

rate, but the channel conditions must be very good for the NodeB to correctly

decode every data block on the first transmission.

� Lower spreading factor – UE must use SF 2.

� Multi-code transmission – Four codes (2 codes with SF2 and 2 codes with SF4) are

used by E-DPDCH.

Shorter TTI – 2ms TTI is needed. Because the maximum transport block size is � Shorter TTI – 2ms TTI is needed. Because the maximum transport block size is

20000 bits with 10ms TTI, the maximum data rate for 10ms TTI is 2Mbps.

� In a practical scenario, the practical maximum data rate will be less than 5.76 Mbps, due

to less than ideal channel conditions, the need for retransmission, and the need to share

the UE power with other channels.


WCDMA HSUPA RAN12 Principle P-30

� In a Release 99 PS network, the NAS layer protocols terminate at the SGSN. The RRC, RLC,

and MAC protocols terminate at the RNC. The Physical Layer protocol terminates at the

NodeB.

� The Release 5 specifications define a new sub-layer of MAC for the downlink called MAC-

hs, which implements the MAC protocols and procedures for HSDPA. This sub-layer

operates at the NodeB and the UE. The location of MAC-hs in the Node B has an

important implication for HSDPA operation.

� Similarly, the Release 6 specifications define a new sub-layer of MAC for the uplink called

MAC-e/es, which implements the MAC protocols and procedures for HSUPA. This sub-


MAC-e/es, which implements the MAC protocols and procedures for HSUPA. This sub-

layer operates at the NodeB (MAC-e), at the RNC (MAC-es), and the UE (MAC-e/es).

� The location of MAC-e in the NodeB has an important implication for HSUPA operation,

allowing for fast retransmissions at the physical Layer. The MAC-es, which is responsible

for reordering of the data packets, is located in the RNC for HSUPA because a UE may be

in soft handover with multiple Node Bs. Transport channel frames are constructed by the

MAC sublayer in the UE and sent over the air interface to each NodeB with which the UE is

in soft handover. The RNC receives identical transport channel frames from each NodeB

over the Iub interfaces and performs reordering.


� Downlink Enhanced L2: Downlink enhanced L2 allows flexible PDU sizes at the RLC layer and

segmentation at the MAC layer on the Uu interface. The feature prevents L2 from becoming the

bottleneck of Uu rate increasing by multiple-input multiple-output (MIMO) and 64QAM.

� Downlink MIMO: Downlink MIMO increases transmission rates through spatial multiplexing and

improves channel qualities through space diversity. The network side can dynamically select single-

or dual-stream transmission based on channel conditions. The peak rate at the MAC layer can reach

28Mbps.

� Downlink 64QAM: Downlink 64QAM allows the use of 64QAM in HSDPA to increase the number

of bits per symbol and thus to obtain higher transmission rates. The peak rate at the MAC layer can

reach 21Mbps. reach 21Mbps.

� Downlink Enhanced CELL_FACH Operation: Downlink Enhanced CELL_FACH Operation allows

the use of HSDPA technologies for the UEs in CELL_FACH, CELL_PCH, and URA_PCH states (RAN11

only supports HSDPA reception in CELL_FACH state.). The purpose is to increase the peak rates in

these states, reduce the signaling transmission delay during service setup or state transition, and

improve user experience.

� CPC: Continuous packet connectivity (CPC) allows uplink and downlink transmissions at regular

intervals. CPC reduces the transmit power and thus prolongs the UE battery life because the UE

does not have to monitor and transmit overhead channels in each TTl. The reduction in the transmit

power also helps to increase the uplink capacity by decreasing the total interference. This

improvement is significant when users such as VoIP users transmit data discontinuously.

� The CPC feature consists of DTX-DTX, and HS-SCCH Less Operation.



� Uplink 16QAM: 16QAM modulation can be used for HSUPA to improve uplink peak date

rate to around 11Mbps.

� Uplink Enhanced L2: Some modifications are introduced in Uu interface layer 2 in uplink

direction to support higher data rate and improve uplink transmission efficiency.

� Downlink MIMO + 64QAM: Before RAN12 MIMO and 64QAM can not be used by one

UE simultaneously. In RAN12 downlink MIMO and 64QAM can be used simultaneously by

one UE to receive HSDPA data. With this technology, the theoretical downlink peak rate

can reach 42Mbps.

� DC-HSDPA (Dual-cell HSDPA): DC-HSDPA allows a UE to set up HSDPA connections with � DC-HSDPA (Dual-cell HSDPA): DC-HSDPA allows a UE to set up HSDPA connections with

two inter-frequency time-synchronous cells that have the same coverage. Theoretically,

DC-HSDPA with 64QAM can provide a peak rate of 42Mbps in the downlink.



� HSPA+ can support three modulation modes: QPSK, 16QAM and 64QAM. Which mode is

used is stilled based on the channel condition of UE.

� The AMC feature introduced with HSDPA enables adaptation of modulation and coding to

varying radio conditions. To improve the advantages of AMC even further, a new

modulation scheme, 64 QAM, is introduced with HSPA+. Theoretically 64QAM can provide

a peak rate of 21 Mbit/s to a single UE. It enables the user with good channel conditions to

download data at higher rates, improves user experience.



� For HSDPA, the peak physical layer throughput is14.4Mbps. To achieve 14.4 Mbps peak

rate, all available SF-16 OVSF codes will be used.

� With MIMO system, the multiplexing gain is obtained with independent data streams on

different antennas. The 2*2 MIMO system defined by 3GPP Release 7 can be 28Mbps.


37Huawei RAN12 MIMO + DL64QAM Feature

� In the dual-stream case, two MAC-ehs PDUs can be transmitted simultaneously in a TTI.

After coding, the two streams are mapped onto the corresponding HS-PDSCHs with the

same orthogonal code.

� In the single-stream case, only one MAC-ehs PDU is transmitted in a TTI, and using

transmit diversity through two antennas can provide higher transmission qualities.

� In this course, we mainly discuss the two streams case.



� The MIMO and 64QAM features are introduced by 3GPP in R7. These two features can be

used respectively. In R7 restricted by the capabilities of UEs, however, a single user cannot

be configured with 64QAM and MIMO at the same time.

� In R8, 64QAM+MIMO can be used by one UE simultaneously to achieve a higher

throughput and better QoS, greatly improving user experience.



� Due to the rapid development of data services, the UMTS needs to improve the spectrum

resource utilization continuously to improve the downlink air interface capabilities and

enrich the service experience of users. The new DC-HSDPA technology introduced in R8

aims to improve the user throughput through larger spectrum bandwidth.

� Dual-cell HSDPA (DC-HSDPA) enables users to receive the HSDPA data sent from two inter-

frequency downlink cells under the same coverage at the same time. The network side can

dynamically select between two carriers for HSDPA transmission.



� DC-HSDPA users belong to both anchor and supplementary carrier cells. The DC-HSDPA

users can be scheduled in each cell. Compared with a single cell, the number of users who

can be scheduled is doubled, users with high-quality channels can be selected through DL

scheduling, and the system throughput is increased. In addition, the channel attenuation

of DC-HSDPA users is different in the two cells, and the probability of high-quality channels

is higher than that of SC-HSDPA users (frequency-selective gain). Therefore, the

throughput of users is increased, and the service delay is reduced.



� Compared with the traditional HSPA technology, DC-HSDPA brings the following gains:

� Improving the peak throughput of users. When the DC-HSDPA and 64QAM

features are used together, the peak throughput can reach 42Mbps.

� Compared with SC-HSDPA, DC-HSDPA features frequency-selective scheduling and

dynamic multi-carrier gain equalization, thus increasing the system capacity. The

gain is more obvious particularly when the load on the two carriers is unequal.

� Greatly reducing the burst service and HTTP service delay. As the user peak rate is

increased, the HTTP service response delay can be greatly reduced, and user service

experience can be improved.experience can be improved.

� Improving the user experience of cell edge users and enhancing the DL coverage.



� Before RAN12, the modulation mode for HSUPA is QPSK. In RAN12, 16QAM for HSUPA is

introduced to improve the peak data.


OWA320010 HSPA & HSPA+ Introduction ISSUE 1.00_staffsHSPA & HSPA+ Introduction ISSUE

Documents

Transcript of OWA320010 HSPA & HSPA+ Introduction ISSUE 1.00_staffsHSPA & HSPA+ Introduction ISSUE